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Tyutyunov Y, Sen D, Banerjee M. Does mutual interference stabilize prey-predator model with Bazykin-Crowley-Martin trophic function? Math Biosci 2024; 372:109201. [PMID: 38636925 DOI: 10.1016/j.mbs.2024.109201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 03/10/2024] [Accepted: 04/12/2024] [Indexed: 04/20/2024]
Abstract
We investigated a system of ordinary differential equations that describes the dynamics of prey and predator populations, taking into account the Allee effect affecting the reproduction of the predator population, and mutual interference amongst predators, which is modeled with the Bazykin-Crowley-Martin (BCM) trophic function. Bifurcation analysis revealed a rich spectrum of bifurcations occurring in the system. In particular, analytical conditions for the saddle-node, Hopf, cusp, and Bogdanov-Takens bifurcations were derived for the model parameters, quantifying the strength of the predator interference, the Allee effect, and the predation efficiency. Numerical simulations verify and illustrate the analytical findings. The main purpose of the study was to test whether the mutual interference in the model with BCM trophic function provides a stabilizing or destabilizing effect on the system dynamics. The obtained results suggest that the model demonstrates qualitatively the same pattern concerning varying the interference strength as other predator-dependent models: both low and very high interference levels increase the risk of predator extinction, while moderate interference has a favorable effect on the stability and resilience of the prey-predator system.
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Affiliation(s)
- Yuri Tyutyunov
- Southern Scientific Centre of the Russian Academy of Sciences, 41 Chekhov St., Rostov-on-Don, 344006, Russia.
| | - Deeptajyoti Sen
- Department of Mathematics & Statics, Faculty of Science, Masaryk University, Kotlářská 2, Brno, 60200, Czech Republic
| | - Malay Banerjee
- Department of Mathematics & Statics, IIT Kanpur, Kalyanpur, 208016, Uttar Pradesh, India
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de Oliveira SJ, Nascimento VF, de Lacerda LB, de Souza JM, Ramalho DG, Izidro YE, De Bortoli SA. Predator-Prey Interaction Between Xylocoris sordidus (Hemiptera: Anthocoridae) and Enneothrips enigmaticus (Thysanoptera: Thripidae). Neotrop Entomol 2024; 53:391-399. [PMID: 38347318 DOI: 10.1007/s13744-023-01126-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Accepted: 12/27/2023] [Indexed: 04/17/2024]
Abstract
The peanut thrips, Enneothrips enigmaticus (Thysanoptera: Thrypidae), is an important pest of the peanut (Arachis hypogaea) in South America. Due to concerns about the environment and human health induced by the extensive use of pesticides in the management control of pests, environmentally and friendlier tactics must be targeted. Thus, this study investigates, for the first time, the behavior of Xylocoris sordidus (Hemiptera: Anthocoridae) as a biological control agent for E. enigmaticus. The methodology included no-choice tests to assess whether the predation rate varies according to the developmental stage of the prey, as well as the predator's developmental stage with the highest predation capacity. Additionally, an analysis of the functional response of adult and 5th instar nymphs of X. sordidus exposed to different densities of E. enigmaticus nymphs (1, 2, 4, 8, 16, and 32) was conducted. The results confirm the predation of peanut thrips by X. sordidus, with a higher predation rate in the nymphal stages of the prey. There was no difference in predation capacity between predator nymphs and adults, and exhibiting a type II functional response. Therefore, the potential of X. sordidus as a biological control agent for E. enigmaticus is confirmed, showing the importance of adopting measures to preserve this predator in peanut crops.
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Affiliation(s)
- Sabrina Juvenal de Oliveira
- Dept of Agricultural Production Sciences, Univ Estadual Paulista (UNESP) - Faculdade de Ciências Agrárias E Veterinárias (FCAV), Jaboticabal, SP, Brazil.
| | - Vinícius Ferraz Nascimento
- Dept of Agricultural Production Sciences, Univ Estadual Paulista (UNESP) - Faculdade de Ciências Agrárias E Veterinárias (FCAV), Jaboticabal, SP, Brazil
| | - Letícia Barbosa de Lacerda
- Dept of Agricultural Production Sciences, Univ Estadual Paulista (UNESP) - Faculdade de Ciências Agrárias E Veterinárias (FCAV), Jaboticabal, SP, Brazil
| | - Joice Mendonça de Souza
- Dept of Agricultural Production Sciences, Univ Estadual Paulista (UNESP) - Faculdade de Ciências Agrárias E Veterinárias (FCAV), Jaboticabal, SP, Brazil
| | - Dagmara Gomes Ramalho
- Dept of Agricultural Production Sciences, Univ Estadual Paulista (UNESP) - Faculdade de Ciências Agrárias E Veterinárias (FCAV), Jaboticabal, SP, Brazil
| | - Yasmin Esteves Izidro
- Dept of Agricultural Production Sciences, Univ Estadual Paulista (UNESP) - Faculdade de Ciências Agrárias E Veterinárias (FCAV), Jaboticabal, SP, Brazil
| | - Sergio Antonio De Bortoli
- Dept of Agricultural Production Sciences, Univ Estadual Paulista (UNESP) - Faculdade de Ciências Agrárias E Veterinárias (FCAV), Jaboticabal, SP, Brazil
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Kulessa AK, Balzani P, Soto I, Toutain M, Haubrock PJ, Kouba A. Assessing the potential phytosanitary threat of the house cricket Acheta domesticus. Sci Total Environ 2024; 917:170376. [PMID: 38281629 DOI: 10.1016/j.scitotenv.2024.170376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 01/20/2024] [Accepted: 01/21/2024] [Indexed: 01/30/2024]
Abstract
Phytosanitary threats can pose substantial risks to global agriculture and ecological systems, affecting biodiversity, human well-being, and food security. Meanwhile, global warming is projected to exacerbate these threats in the future. One in Europe already widely distributed potential phytosanitary threat that may benefit from global warming is the house cricket Acheta domesticus. This study explored the potential of A. domesticus as a relevant non-native phytosanitary threat under changing climatic conditions by conducting a series of functional response experiments across a temperature gradient (20, 25, and 30 °C). Acheta domesticus exhibited comparable patterns of seed consumption and functional responses. Seed type (millet seeds, wheat grains) and temperature increase influenced the damage inflicted on seeds, with softer and smaller seeds being more susceptible to damage, further amplified by warmer temperatures. The study's outcomes underline the phytosanitary threat that A. domesticus may pose. Considering the species' established presence and adaptable nature in urban environments exacerbates the potential for A. domesticus to transition to rural and agricultural areas. Its increasing production as a food item, paired with the here-identified potential to damage seeds, emphasizes the need for proactive and science-based strategies to address emerging phytosanitary threats driven by non-native species under changing climatic conditions. As global temperatures continue to rise, the assessment and management of potential pest species like A. domesticus will be crucial for safeguarding agriculture productivity and ecological balance.
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Affiliation(s)
- Anna K Kulessa
- Ruhr University Bochum, Faculty of Biology and Biotechnology, 44801 Bochum, Germany; University of Duisburg-Essen, Faculty of Biology, 45141 Essen, Germany; Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, University of South Bohemia in České Budějovice, 389 25 Vodňany, Czech Republic.
| | - Paride Balzani
- Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, University of South Bohemia in České Budějovice, 389 25 Vodňany, Czech Republic
| | - Ismael Soto
- Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, University of South Bohemia in České Budějovice, 389 25 Vodňany, Czech Republic
| | - Mathieu Toutain
- Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, University of South Bohemia in České Budějovice, 389 25 Vodňany, Czech Republic; Université de Rennes, CNRS, ECOBIO [(Ecosystèmes, biodiversité, évolution)], 35000 Rennes, France
| | - Phillip J Haubrock
- Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, University of South Bohemia in České Budějovice, 389 25 Vodňany, Czech Republic; Department of River Ecology and Conservation, Senckenberg Research Institute and Natural History Museum Frankfurt, 63571 Gelnhausen, Germany; CAMB, Center for Applied Mathematics and Bioinformatics, Gulf University for Science and Technology, Hallawy 32093, Kuwait
| | - Antonín Kouba
- Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, University of South Bohemia in České Budějovice, 389 25 Vodňany, Czech Republic
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Li Y, Zhang B, Zhang J, Yang N, Yang D, Zou K, Xi Y, Chen G, Zhang X. The inappropriate application of imidacloprid destroys the ability of predatory natural enemies to control pests in the food chain: A case study of the feeding behavior of Orius similis on Frankliniella occidentalis. Ecotoxicol Environ Saf 2024; 272:116040. [PMID: 38306817 DOI: 10.1016/j.ecoenv.2024.116040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 01/02/2024] [Accepted: 01/27/2024] [Indexed: 02/04/2024]
Abstract
Insecticides are an indispensable and important tool for agricultural production. However, the inappropriate application of insecticides can cause damage to the food chain and ecosystem. Orius similis is an important predatory and natural enemy of Frankliniella occidentalis. Imidacloprid is widely used to control pests, but will inevitably exert adverse effects on O. similis. In order to determine the effect of different imidacloprid treatments on the ability of O. similis to prey on the 2nd-instar nymphs of F. occidentalis, we determined the toxicity and predation of imidacloprid on different stages of O. similis under contact and ingestion treatments. In addition, we used the Holling disc equation to evaluate the ability of O. similis to search and exhibit predatory activity following contact and ingestion treatments. Analysis showed that the highest LC10 and LC20 values for imidacloprid contact and ingestion toxicity treatment were 17.06 mg/L and 23.74 mg/L, respectively. Both imidacloprid treatments led toa reduction in the predatory of O. similis on prey. The functional responses of the 3rd to 5th instar nymphs, along with female and male O. similis adults to the 2nd-instar nymphs of F. occidentalis were consistent with the Holling type II response following contact and ingestion with imidacloprid. However, following imidacloprid treatment, the handing time (Th) of O. similis with single F. occidentalis was prolonged and the instantaneous attack rate (a) was reduced after imidacloprid treatment. The predatory capacity (a/Th) of female O. similis adults when treated with the LC10 concentration of imidacloprid by ingestion was 52.85; this was lower than that of the LC10 concentration of imidacloprid in the contact treatment (57.67). The extent of predation of O. similis on the 2nd-instar nymphs of F. occidentalis was positively correlated with prey density, although the search effect was negatively correlated with prey density. The most extensive search effect was exhibited by adult O. similis females. Simulations with the Hessell-Varley interference model showed that an increase in the number of O. similis would reduce search efficiency regardless of whether they were treated with imidacloprid or not. Thus, O. similis, especially female adults, exhibited strong potential for controlling the 2nd-instar nymphs of F. occidentalis. The toxicity of ingestion following treatment with the same concentration of imidacloprid in O. similis was greater than that of contact treatment. When using O. similis to control F. occidentalis in the field, we should increase the number of female adults released, and prolong the interval between imidacloprid treatment and O. similis exposure. This strategy will improve the control ability of O. similis, coordinate both chemical and biological control, reduce the impact of pesticides on the environment, and improve the efficiency of agricultural production.
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Affiliation(s)
- Yiru Li
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, College of Plant Protection, Yunnan Agricultural University, 650201 Kunming, China
| | - Bo Zhang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, College of Plant Protection, Yunnan Agricultural University, 650201 Kunming, China
| | - Jinlong Zhang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, College of Plant Protection, Yunnan Agricultural University, 650201 Kunming, China
| | - Nian Yang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, College of Plant Protection, Yunnan Agricultural University, 650201 Kunming, China
| | - Dan Yang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, College of Plant Protection, Yunnan Agricultural University, 650201 Kunming, China
| | - Kun Zou
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, College of Plant Protection, Yunnan Agricultural University, 650201 Kunming, China
| | - Yangyan Xi
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, College of Plant Protection, Yunnan Agricultural University, 650201 Kunming, China
| | - Guohua Chen
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, College of Plant Protection, Yunnan Agricultural University, 650201 Kunming, China
| | - Xiaoming Zhang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, College of Plant Protection, Yunnan Agricultural University, 650201 Kunming, China.
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Mumtaz M, Rahman VJ, Saba T, Huang T, Zhang Y, Jiang C, Li Q. Functional response of Neoseiulus californicus (Acari: Phytoseiidae) to Tetranychus urticae (Acari: Tetranychidae) at different temperatures. PeerJ 2023; 11:e16461. [PMID: 38034871 PMCID: PMC10688301 DOI: 10.7717/peerj.16461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 10/23/2023] [Indexed: 12/02/2023] Open
Abstract
Environmental factors like temperature have a great impact on the predation potential of biological control agents. In the present study, the functional response of the predatory mite Neoseiulus californicus (Acari: Phytoseiidae) to the pest mite Tetranychus urticae (Acari: Tetranychidae) at moderate to high temperatures under laboratory conditions was determined. The study aimed to understand the prey-predator interaction under different temperatures and prey densities. Five constant temperatures (24 °C, 27 °C, 30 °C, 33 °C, and 36 °C), and thirteen prey densities (4, 5, 8, 10, 12, 15, 16, 20, 24, 25, 30, 32, and 40) of each stage (adult, nymph, larvae, and egg stage) were employed in the experiment. Observations were made 24 h after the start of each experiment. Results revealed that the predatory mites showed type II functional response to adult females of T. urticae, whereas type I to other stages (nymphs, larvae, and eggs) of T. urticae. The predation capability of adult predatory mites on T. urticae was significant at 24-36 °C. The instantaneous attack rate (a) of N. californicus increased and the handling time (Th) decreased with an increase in temperature. The maximum attack rate was recorded at 36 °C (1.28) for the egg stage. The longest handling time was (0.78) for the larval stage of T. urticae at 30 °C. Daily consumption increased with increasing prey density. Maximum daily consumption was observed at 33 °C (30.00) at the prey density of 40. Searching efficiency decreased with the increase in prey density but was found to increase with the rise in temperature. N. californicus was found to be voracious on the larval and egg stages. Conclusively, the incorporation of N. californicus at earlier stages (larvae and eggs) of T. urticae would be beneficial under warm conditions because managing a pest at its initial stage will save the crop from major losses. The results presented in this study at various temperatures will be helpful in different areas with different temperature extremes. The results of the functional response can also be applied to mass rearing, quality testing, and integrated pest management programmes.
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Affiliation(s)
- Maryam Mumtaz
- College of Agronomy, Department of Agricultural Entomology, Sichuan Agricultural University, Chegndu, Sichuan, China
| | | | - Tahseen Saba
- College of Forestry, Sichuan Agricultural University, Chengdu, Sichuan, China
| | - Tingting Huang
- College of Agronomy, Department of Agricultural Entomology, Sichuan Agricultural University, Chegndu, Sichuan, China
| | - Yuxin Zhang
- College of Agronomy, Department of Agricultural Entomology, Sichuan Agricultural University, Chegndu, Sichuan, China
| | - Chunxian Jiang
- College of Agronomy, Department of Agricultural Entomology, Sichuan Agricultural University, Chegndu, Sichuan, China
| | - Qing Li
- College of Agronomy, Department of Agricultural Entomology, Sichuan Agricultural University, Chengdu, Sichuan, China
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Barraquand F. No sensitivity to functional forms in the Rosenzweig-MacArthur model with strong environmental stochasticity. J Theor Biol 2023; 572:111566. [PMID: 37422068 DOI: 10.1016/j.jtbi.2023.111566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 06/04/2023] [Accepted: 06/26/2023] [Indexed: 07/10/2023]
Abstract
The classic Rosenzweig-MacArthur predator-prey model has been shown to exhibit, like other coupled nonlinear ordinary differential equations (ODEs) from ecology, worrying sensitivity to model structure. This sensitivity manifests as markedly different community dynamics arising from saturating functional responses with nearly identical shapes but different mathematical expressions. Using a stochastic differential equation (SDE) version of the Rosenzweig-MacArthur model with the three functional responses considered by Fussmann & Blasius (2005), I show that such sensitivity seems to be solely a property of ODEs or stochastic systems with weak noise. SDEs with strong environmental noise have by contrast very similar fluctuations patterns, irrespective of the mathematical formula used. Although eigenvalues of linearized predator-prey models have been used as an argument for structural sensitivity, they can also be an argument against structural sensitivity. While the sign of the eigenvalues' real part is sensitive to model structure, its magnitude and the presence of imaginary parts are not, which suggests noise-driven oscillations for a broad range of carrying capacities. I then discuss multiple other ways to evaluate structural sensitivity in a stochastic setting, for predator-prey or other ecological systems.
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Affiliation(s)
- Frédéric Barraquand
- Institute of Mathematics of Bordeaux, CNRS & University of Bordeaux, Talence, France.
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da Silva Nunes G, de Souza JM, Ramalho DG, De Bortoli SA, Polanczyk RA. Bacillus thuringiensis-based bioinsecticides affect predation of Euborellia annulipes on diamondback moth larvae. Environ Sci Pollut Res Int 2023; 30:90730-90740. [PMID: 37462876 DOI: 10.1007/s11356-023-28814-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Accepted: 07/12/2023] [Indexed: 08/24/2023]
Abstract
Interactions between earwigs and entomopathogens, such as Bacillus thuringiensis (Bt), are still poorly understood. This study tested whether Bt-based bioinsecticides have any effect on the predation of Euborellia annulipes (Lucas) (Dermaptera: Anisolabididae) on Plutella xylostella (L.) (Lepidoptera: Plutellidae), one of the pests with the largest number of cases of use and resistance to Bt. Fourth instar larvae were Bt infected by feeding on collard green leaves treated with Dipel®WG and XenTari®WG at the manufacturer-recommended doses. We used one no-choice condition, in which the predator had access to uninfected or Bt-infected larvae separately, and four free-choice conditions: uninfected vs Dipel®-infected larvae, uninfected vs XenTari®-infected larvae, Dipel®-infected vs XenTari®-infected larvae, and uninfected vs Bt-infected larvae with both bioinsecticides. Uninfected larvae were less consumed than those infected by both Bt-bioinsecticides in the no-choice condition. There was a higher consumption of uninfected over Dipel®-infected larvae in the free-choice condition. Overall, uninfected larvae were preferred over both Bt-based bioinsecticides infected larvae. We also used six different prey densities. The ringlegged earwig's predation rate enhanced as the prey population density increased, but the functional response was not affected by Bt-infection, being type II. The predator invested a low amount of handling time on Bt-fed prey and increased the maximum predation rate. Bt-based bioinsecticides cause effects on E. annulipes predation by altering their feeding preference and some aspects of its predatory behavior. The results of our study provide an important background for understanding interactions between earwigs and Bt. In addition, they can be used for decision making during approaches to integrated P. xylostella management.
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Affiliation(s)
- Gilmar da Silva Nunes
- Instituto Federal Goiano, Rodovia Sul Goiana, km 01, Zona Rural, CEP, Rio Verde, GO, 75901-970, Brazil.
| | - Joice Mendonça de Souza
- Universidade Estadual Paulista, Via de Acesso Prof. Paulo Donato Castelane, CEP, Jaboticabal, SP, 14884-900, Brazil
| | - Dagmara Gomes Ramalho
- Universidade Estadual Paulista, Via de Acesso Prof. Paulo Donato Castelane, CEP, Jaboticabal, SP, 14884-900, Brazil
| | - Sergio Antonio De Bortoli
- Universidade Estadual Paulista, Via de Acesso Prof. Paulo Donato Castelane, CEP, Jaboticabal, SP, 14884-900, Brazil
| | - Ricardo Antonio Polanczyk
- Universidade Estadual Paulista, Via de Acesso Prof. Paulo Donato Castelane, CEP, Jaboticabal, SP, 14884-900, Brazil
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Bansaye V, Cloez B. From the distributions of times of interactions to preys and predators dynamical systems. J Math Biol 2023; 87:2. [PMID: 37284989 DOI: 10.1007/s00285-023-01925-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 12/05/2022] [Accepted: 03/09/2023] [Indexed: 06/08/2023]
Abstract
We consider a stochastic individual based model where each predator searches and then manipulates its prey or rests during random times. The time distributions may be non-exponential and density dependent. An age structure allows to describe these interactions and get a Markovian setting. The process is characterized by a measure-valued stochastic differential equation. We prove averaging results in this infinite dimensional setting and get the convergence of the slow-fast macroscopic prey predator process to a two dimensional dynamical system. We recover classical functional responses. We also get new forms arising in particular when births and deaths of predators are affected by the lack of food.
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Affiliation(s)
- Vincent Bansaye
- CMAP, CNRS, École polytechnique, Institut Polytechnique de Paris, 91120, Palaiseau, France.
| | - Bertrand Cloez
- MISTEA, INRAE, Institut Agro, Université Montpellier, Montpellier, France
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Griffith RM, Cuthbert RN, Johnson JV, Hardiman G, Dick JTA. Resilient amphipods: Gammarid predatory behaviour is unaffected by microplastic exposure and deoxygenation. Sci Total Environ 2023; 883:163582. [PMID: 37086992 DOI: 10.1016/j.scitotenv.2023.163582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 04/09/2023] [Accepted: 04/15/2023] [Indexed: 05/03/2023]
Abstract
Microplastics are a ubiquitous and persistent form of pollution globally, with impacts cascading from the cellular to ecosystem level. However, there is a paucity in understanding interactions between microplastic pollution with other environmental stressors, and how these could affect ecological functions and services. Freshwater ecosystems are subject to microplastic input from anthropogenic activities (eg. wastewater), but are also simultaneously exposed to many other stressors, particularly reduced dissolved oxygen availability associated with climatic warming and pollutants, as well as biological invasions. Here, we employ the comparative functional response method (CFR; quantifying and comparing organism resource use as a function of resource density) to investigate the relative impact of different microplastic concentrations and oxygen regimes on predatory trophic interactions of a native and an invasive alien gammarid (Gammarus duebeni and Gammarus pulex). No significant effect on trophic interaction strengths was found from very high concentrations of microplastics (200 mp/L and 200,000 mp/L) or low oxygen (40 %) stressors on either species. Additionally, both gammarid species exhibited significant Type II functional responses, with attack rates and handling times not significantly affected by microplastics, oxygen or gammarid invasion status. Thus, both species showed resistance to the simultaneous effects of microplastics and deoxygenation in terms of feeding behaviour. Based on these findings, we suggest that the trophic function, in terms of predation rate, of Gammarus spp. may be sustained under acute bouts of microplastic pollution even in poorly‑oxygenated waters. This is the first study to investigate microplastic and deoxygenation interactions and to find no evidence for an interaction on a key invertebrate ecosystem service. We argue that our CFR methods can help understand and predict the future ecological ramifications of microplastics and other stressors across taxa and habitats.
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Affiliation(s)
- Rose M Griffith
- School of Biological Sciences, Queen's University Belfast, 19 Chlorine Gardens, Belfast, BT9 5DL, Northern Ireland, UK; Queen's Marine Laboratory, Queen's University Belfast, 12-13 The Strand, Portaferry, BT22 1PF, Northern Ireland, UK.
| | - Ross N Cuthbert
- School of Biological Sciences, Queen's University Belfast, 19 Chlorine Gardens, Belfast, BT9 5DL, Northern Ireland, UK; Queen's Marine Laboratory, Queen's University Belfast, 12-13 The Strand, Portaferry, BT22 1PF, Northern Ireland, UK; Institute for Global Food Security, Queen's University Belfast, 19 Chlorine Gardens, Belfast, BT9 5DL, Northern Ireland, UK
| | - Jack V Johnson
- School of Biological Sciences, Queen's University Belfast, 19 Chlorine Gardens, Belfast, BT9 5DL, Northern Ireland, UK; Queen's Marine Laboratory, Queen's University Belfast, 12-13 The Strand, Portaferry, BT22 1PF, Northern Ireland, UK
| | - Gary Hardiman
- Institute for Global Food Security, Queen's University Belfast, 19 Chlorine Gardens, Belfast, BT9 5DL, Northern Ireland, UK
| | - Jaimie T A Dick
- School of Biological Sciences, Queen's University Belfast, 19 Chlorine Gardens, Belfast, BT9 5DL, Northern Ireland, UK; Queen's Marine Laboratory, Queen's University Belfast, 12-13 The Strand, Portaferry, BT22 1PF, Northern Ireland, UK; Institute for Global Food Security, Queen's University Belfast, 19 Chlorine Gardens, Belfast, BT9 5DL, Northern Ireland, UK
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Parker B, Britton JR, Green ID, Amat-Trigo F, Andreou D. Parasite infection but not chronic microplastic exposure reduces the feeding rate in a freshwater fish. Environ Pollut 2023; 320:121120. [PMID: 36682615 DOI: 10.1016/j.envpol.2023.121120] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 01/15/2023] [Accepted: 01/17/2023] [Indexed: 06/17/2023]
Abstract
Microplastics (plastics <5 mm) are an environmental contaminant that can negatively impact the behaviour and physiology of aquatic biota. Although parasite infection can also alter the behaviour and physiology of their hosts, few studies have investigated how microplastic and parasite exposure interact to affect hosts. Accordingly, an interaction experiment tested how exposure to environmentally relevant microplastic concentrations and the trophically transmitted parasite Pomphorhynchus tereticollis affected the parasite load, condition metrics and feeding rate of the freshwater fish final host chub Squalius cephalus. Microplastic exposure was predicted to increase infection susceptibility, resulting in increased parasite loads, whereas parasite and microplastic exposure were expected to synergistically and negatively impact condition indices and feeding rates. Following chronic (≈170 day) dietary microplastic exposure, fish were exposed to a given number of gammarids (4/8/12/16/20), with half of the fish presented with parasite infected individuals, before a comparative functional response experiment tested differences in feeding rates on different live prey densities. Contrary to predictions, dietary microplastic exposure did not affect parasite abundance at different levels of parasite exposure, specific growth rate was the only condition index that was lower for exposed but unexposed fish, with no single or interactive effects of microplastic exposure detected. However, parasite infected fish had significantly lower feeding rates than unexposed fish in the functional response experiment, with exposed but unexposed fish also showing an intermediate decrease in feeding rates. Thus, the effects of parasitism on individuals were considerably stronger than microplastic exposure, with no evidence of interactive effects. Impacts of environmentally relevant microplastic levels might thus be relatively minor versus other stressors, with their interactive effects difficult to predict based on their single effects.
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Affiliation(s)
- Ben Parker
- Department of Life and Environmental Sciences, Faculty of Science and Technology, Bournemouth University, Poole, Dorset, BH12 5BB, UK.
| | - J Robert Britton
- Department of Life and Environmental Sciences, Faculty of Science and Technology, Bournemouth University, Poole, Dorset, BH12 5BB, UK
| | - Iain D Green
- Department of Life and Environmental Sciences, Faculty of Science and Technology, Bournemouth University, Poole, Dorset, BH12 5BB, UK
| | - Fátima Amat-Trigo
- Department of Life and Environmental Sciences, Faculty of Science and Technology, Bournemouth University, Poole, Dorset, BH12 5BB, UK
| | - Demetra Andreou
- Department of Life and Environmental Sciences, Faculty of Science and Technology, Bournemouth University, Poole, Dorset, BH12 5BB, UK
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Coughlan NE, Dickey JWE, Dick JTA, Médoc V, McCard M, Lacroix G, Fiorini S, Millot A, Cuthbert RN. When worlds collide: Invader-driven benthic habitat complexity alters predatory impacts of invasive and native predatory fishes. Sci Total Environ 2022; 843:156876. [PMID: 35760170 DOI: 10.1016/j.scitotenv.2022.156876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2022] [Revised: 05/27/2022] [Accepted: 06/18/2022] [Indexed: 06/15/2023]
Abstract
Interactions between multiple invasive alien species (IAS) might increase their ecological impacts, yet relatively few studies have attempted to quantify the effects of facilitative interactions on the success and impact of aquatic IAS. Further, the effect of abiotic factors, such as habitat structure, have lacked consideration in ecological impact prediction for many high-profile IAS, with most data acquired through simplified assessments that do not account for real environmental complexities. In the present study, we assessed a potential facilitative interaction between a predatory invasive fish, the Ponto-Caspian round goby (Neogobius melanostomus), and an invasive bivalve, the Asian clam (Corbicula fluminea). We compared N. melanostomus functional responses (feeding-rates under different prey densities) to a co-occurring endangered European native analogue fish, the bullhead (Cottus gobio), in the presence of increased levels of habitat complexity driven by the accumulation of dead C. fluminea biomass that persists within the environment (i.e. 0, 10, 20 empty bivalve shells). Habitat complexity significantly influenced predation, with consumption in the absence of shells being greater than where 10 or 20 shells were present. However, at the highest shell density, invasive N. melanostomus maximum feeding-rates and functional response ratios were substantially higher than those of native C. gobio. Further, the Relative Impact Potential metric, by combining per capita effects and population abundances, indicated that higher shell densities exacerbate the relative impact of the invader. It therefore appears that N. melanostomus can better tolerate higher IAS shell abundances when foraging at high prey densities, suggesting the occurrence of an important facilitative interaction. Our data are thus fully congruent with field data that link establishment success of N. melanostomus with the presence of C. fluminea. Overall, we show that invader-driven benthic habitat complexity can alter the feeding-rates and thus impacts of predatory fishes, and highlight the importance of inclusion of abiotic factors in impact prediction assessments for IAS.
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Affiliation(s)
- Neil E Coughlan
- School of Biological, Earth & Environmental Sciences, University College Cork, Distillery Fields, North Mall, Cork, Ireland; Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, 19 Chlorine Gardens, Belfast, Northern Ireland BT9 5DL, UK.
| | - James W E Dickey
- Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, 19 Chlorine Gardens, Belfast, Northern Ireland BT9 5DL, UK; Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), 12587 Berlin, Germany; Freie Universität Berlin, Institute of Biology, Königin-Luise-Str. 1-3, 14195 Berlin, Germany; GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel, 24105 Kiel, Germany
| | - Jaimie T A Dick
- Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, 19 Chlorine Gardens, Belfast, Northern Ireland BT9 5DL, UK
| | - Vincent Médoc
- Equipe Neuro Ethologie Sensorielle, ENES/Neuro-PSI CNRS UMR 9197, Université de Lyon/Saint-Etienne, Saint-Etienne, France
| | - Monica McCard
- Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, 19 Chlorine Gardens, Belfast, Northern Ireland BT9 5DL, UK
| | - Gérard Lacroix
- iEES-Paris, Institut d'Ecologie et des Sciences de l'Environnement de Paris, UMR 7618 (CNRS, INRAE, IRD, Sorbonne Université, UPEC, Université de Paris), CC237 Paris, France; Ecole Normale Supérieure, PSL Research University, CNRS, Centre de Recherche en Écologie Expérimentale et Prédictive (CEREEP-Ecotron Ile-De-France), UAR 3194 Saint-Pierre-lès-Nemours, France
| | - Sarah Fiorini
- Ecole Normale Supérieure, PSL Research University, CNRS, Centre de Recherche en Écologie Expérimentale et Prédictive (CEREEP-Ecotron Ile-De-France), UAR 3194 Saint-Pierre-lès-Nemours, France
| | - Alexis Millot
- Ecole Normale Supérieure, PSL Research University, CNRS, Centre de Recherche en Écologie Expérimentale et Prédictive (CEREEP-Ecotron Ile-De-France), UAR 3194 Saint-Pierre-lès-Nemours, France
| | - Ross N Cuthbert
- Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, 19 Chlorine Gardens, Belfast, Northern Ireland BT9 5DL, UK
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McCoy MW, Hamman E, Albecker M, Wojdak J, Vonesh JR, Bolker BM. Incorporating nonlinearity with generalized functional responses to simulate multiple predator effects. PeerJ 2022; 10:e13920. [PMID: 35999847 PMCID: PMC9393008 DOI: 10.7717/peerj.13920] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 07/28/2022] [Indexed: 01/19/2023] Open
Abstract
Predicting the combined effects of predators on shared prey has long been a focus of community ecology, yet quantitative predictions often fail. Failure to account for nonlinearity is one reason for this. Moreover, prey depletion in multiple predator effects (MPE) studies generates biased predictions in applications of common experimental and quantitative frameworks. Here, we explore additional sources of bias stemming from nonlinearities in prey predation risk. We show that in order to avoid bias, predictions about the combined effects of independent predators must account for nonlinear size-dependent risk for prey as well as changes in prey risk driven by nonlinear predator functional responses and depletion. Historical failure to account for biases introduced by well-known nonlinear processes that affect predation risk suggest that we may need to reevaluate the general conclusions that have been drawn about the ubiquity of emergent MPEs over the past three decades.
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Affiliation(s)
- Michael W. McCoy
- Florida Atlantic University (Harbor Branch Campus), Ft. Pierce, FL, United States
| | - Elizabeth Hamman
- St. Mary’s College of Maryland, St Mary’s City, MD, United States
| | | | | | - James R. Vonesh
- Virginia Commonwealth University, Richmond, VA, United States
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13
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Ishikawa K, Wu H, Mitarai S, Genin A. Effects of prey density and flow speed on plankton feeding by garden eels: A flume study. J Exp Biol 2022; 225:274794. [PMID: 35315487 PMCID: PMC9124482 DOI: 10.1242/jeb.243655] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 03/16/2022] [Indexed: 11/24/2022]
Abstract
Feeding by zooplanktivorous fish depends on their foraging movements and the flux of prey to which they are exposed. While prey flux is a linear function of zooplankton density and flow speed, those two factors are expected to contribute differently to fish movements. Our objective was to determine the effects of these factors for garden eels, stationary fish that feed while anchored to the sandy bottom by keeping the posterior parts of their bodies inside a burrow. Using a custom-made flume with a sandy bottom, we quantified the effects of prey density and flow speed on feeding rates by spotted garden eels (Heteroconger hassi). Feeding rates increased linearly with prey density. However, feeding rates did not show a linear relationship with flow speed and decreased at 0.25 m s−1. Using label-free tracking of body points and 3D movement analysis, we found that the reduction in feeding rates was related to modulation of the eel's movements, whereby the expected increase in energy expenditure was avoided by reducing exposure and drag. No effects of flow speed on strike speed, reactive distance or vectorial dynamic body acceleration (VeDBA) were found. A foraging model based on the body length extended from the burrow showed correspondence with observations. These findings suggest that as a result of their unique foraging mode, garden eels can occupy self-made burrows in exposed shelter-free sandy bottoms where they can effectively feed on drifting zooplankton. Summary: Analysis of feeding by anchored garden eels in a flume shows their unique strategies, modulating dependence on burrows and foraging movements, to enable effective feeding at a wide range of flow speeds.
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Affiliation(s)
- Kota Ishikawa
- Marine Biophysics Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa, Japan
| | - Heng Wu
- Marine Biophysics Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa, Japan
| | - Satoshi Mitarai
- Marine Biophysics Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa, Japan
| | - Amatzia Genin
- The Interuniversity Institute for Marine Sciences in Eilat and Department of Ecology, Evolution and Behavior, The Hebrew University of Jerusalem, Eilat, Israel
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14
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Yong AYP, Lim SSL. Plasticity of Foraging Strategies Adopted by the Painted Ghost Crab, Ocypode gaudichaudii, in Response to in situ Food Resource Manipulation Experiments. Zool Stud 2021; 60:e37. [PMID: 34966458 DOI: 10.6620/ZS.2021.60-37] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Accepted: 04/19/2021] [Indexed: 11/18/2022]
Abstract
The feeding strategies of Ocypode gaudichaudii at two sandy beaches, Culebra Beach (CB) and Playa Venao (PV) in Panama, were studied via three experiments. Two separate manipulative in situ experiments were conducted to determine how the densities of food resources and the size of the supplemented food offered to the crabs can affect their diet and food handling behavior. The third experiment, a transplantation study, was also conducted to determine the plasticity of the feeding behavior of the displaced crabs. In the first experiment, freshly-emerged crabs showed different feeding modes when washed-sediment was seeded with different densities of diatoms and rove beetles, which suggests that they are optimal foragers. Crabs hoarded food in the second experiment when food augmentation was performed, in which small and large food pellets were placed around the burrows at the beginning and end of the crabs' feeding cycle. All freshly-emerged crabs from both sites foraged on the small pellets outside their burrows and did not cache food; when pellets were provided at the end of the feeding cycle, crabs from CB fed on some of the small pellets and returned to their burrows with the uneaten pellets left on the surface, whereas crabs at PV picked up all the small food pellets and transferred them into their burrows over several trips before plugging their burrow entrances. Only the crabs from PV carried the large food pellets supplemented at the start and end of the feeding cycle into their burrows. In contrast, the crabs at CB often left behind the partially-eaten pellets on the sand surface, probably due to the increased risk of predation associated with the prolonged handling time of the large food pellets. Excavation of the burrows of the crabs that hoarded food showed that all the pellets were deposited at the bend of the burrows, indicating that they were not consumed immediately. Crabs that fed in droves at PV stopped droving and foraged around their burrows after being transplanted to CB. This is the first documentation of food hoarding in a sandy beach macroinvertebrate at a resource-impoverished habitat. The plasticity of feeding strategies adopted by the painted ghost crab in response to different densities of food resources in the habitat could be an adaptation to the dynamic sandy beach environment.
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15
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Cuthbert RN, Briski E. Temperature, not salinity, drives impact of an emerging invasive species. Sci Total Environ 2021; 780:146640. [PMID: 33774308 DOI: 10.1016/j.scitotenv.2021.146640] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 03/16/2021] [Accepted: 03/17/2021] [Indexed: 06/12/2023]
Abstract
Biological invasions are a growing ecological and socioeconomic problem worldwide. While robust predictions of impactful future invaders are urgently needed, understandings of invader impacts have been challenged by context-dependencies. In aquatic systems in particular, future climate change could alter the impacts of invasive non-native species. Widespread warming coupled with sea freshening may exacerbate ecological impacts of invaders in marine environments, compromising ecosystem structure, function and stability. We examined how multiple abiotic changes affect the potential ecological impact of an emerging invasive non-native species from the Ponto-Caspian region - a notorious origin hotspot for invaders, characterised by high salinity and temperature variation. Using a comparative functional response (feeding rates across prey densities) approach, the potential ecological impacts of the gammarid Pontogammarus maeoticus towards native chironomid prey were examined across a range of current and future temperature (18, 22 °C) and salinity (14, 10, 6, 2 ppt) regimes in a factorial design. Feeding rates of P. maeoticus on prey significantly increased with temperature (by 60%), but were not significantly affected by salinity regime. Gammarids displayed significant Type II functional responses, with attack rates not significantly affected by warming across all salinities. Handling times were, however, shortened by warming, and thus maximum feeding rates significantly increased, irrespective of salinity regime. Functional responses were significantly different following warming at high prey densities under all salinities, except under the ambient 10 ppt. Euryhalinity of invasive non-native species from the Ponto-Caspian region thus could allow sustained ecological impacts across a range of salinity regimes. These results corroborate high invasion success and field impacts of Ponto-Caspian gammarids in brackish through to freshwater ecosystems. Climate warming will likely worsen the potential ecological impact of P. maeoticus. With invasions growing worldwide, quantifications of how combined elements of climate change will alter the impacts of emerging invasive non-native species are needed.
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Affiliation(s)
- Ross N Cuthbert
- GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel, Kiel, Germany.
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16
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Cunningham EM, Cuthbert RN, Coughlan NE, Kregting L, Cairnduff V, Dick JTA. Microplastics do not affect the feeding rates of a marine predator. Sci Total Environ 2021; 779:146487. [PMID: 34030230 DOI: 10.1016/j.scitotenv.2021.146487] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 02/24/2021] [Accepted: 03/11/2021] [Indexed: 05/12/2023]
Abstract
Microplastics may affect the physiology, behaviour and populations of aquatic and terrestrial fauna through many mechanisms, such as direct consumption and sensory disruption. However, the majority of experimental studies have employed questionably high dosages of microplastics that have little environmental relevance. Predation, in particular, is a key trophic interaction that structures populations and communities and influences ecosystem functioning, but rarely features in microplastic research. Here, we quantify the effects of low (~65-114 MP/L) and high (~650-1140 MP/L) microplastic concentrations on the feeding behaviour of a ubiquitous and globally representative key marine predator, the shore crab, Carcinus maenas. We used a functional response approach (predator consumption across prey densities) to determine crab consumption rates towards a key marine community prey species, the blue mussel Mytilus edulis, under low and high microplastic concentrations with acute (8h) and chronic (120h) microplastic exposure times. For both the acute and chronic microplastic exposure experiments, proportional prey consumption by crabs did not differ with respect to microplastic concentration, but significantly decreased over increasing prey densities. The crabs thus displayed classical, hyperbolic Type II functional responses in all experimental groups, characterised by high consumption rates at low prey densities. Crab attack rates, handling times and maximum feeding rates (i.e. functional response curves) were not significantly altered under lower or higher microplastics concentrations, or by acute or chronic microplastic exposures. Here, we show that functional response analyses could be widely employed to ascertain microplastic impacts on consumer-resource interactions. Furthermore, we suggest that future studies should adopt both acute and chronic microplastic exposure regimes, using environmentally-relevant microplastic dosages and types as well as elevated future scenarios of microplastic concentrations.
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Affiliation(s)
- Eoghan M Cunningham
- Queen's University Marine Laboratory, Queen's University Belfast, 12-13 The Strand, Portaferry BT22 1PF, UK.
| | - Ross N Cuthbert
- GEOMAR, Helmholtz-Zentrum für Ozeanforschung Kiel, Düsternbrooker Weg 20, 24105 Kiel, Germany; Queen's University Marine Laboratory, Queen's University Belfast, 12-13 The Strand, Portaferry BT22 1PF, UK
| | - Neil E Coughlan
- School of Biological, Earth and Environmental Sciences, University College Cork, Distillery Fields, North Mall, Cork, Ireland; Queen's University Marine Laboratory, Queen's University Belfast, 12-13 The Strand, Portaferry BT22 1PF, UK
| | - Louise Kregting
- School of Natural and Built Environment, Queen's University Belfast, Belfast BT9 5BN, UK; Queen's University Marine Laboratory, Queen's University Belfast, 12-13 The Strand, Portaferry BT22 1PF, UK
| | - Victoria Cairnduff
- Queen's University Marine Laboratory, Queen's University Belfast, 12-13 The Strand, Portaferry BT22 1PF, UK
| | - Jaimie T A Dick
- Queen's University Marine Laboratory, Queen's University Belfast, 12-13 The Strand, Portaferry BT22 1PF, UK; Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, BT9 5DL, UK
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Kumari S, Suroshe SS, Kumar D, Budhlakoti N, Yana V. Foraging behaviour of Scymnus coccivora Ayyar against cotton mealybug Phenacoccus solenopsis Tinsley. Saudi J Biol Sci 2021; 28:3799-3805. [PMID: 34220234 PMCID: PMC8241695 DOI: 10.1016/j.sjbs.2021.03.051] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 03/17/2021] [Accepted: 03/21/2021] [Indexed: 11/16/2022] Open
Abstract
Predation is one of the significant biotic mortality factors reducing the insect pest population as functional response and the numerical response of the predator are the key factor regulating the population dynamics of predator prey species. This study is aimed to evaluate the functional response of all the developmental stages of Scymnus coccivora Ayyar (Coleoptera: Coccinellidae) against the different densities of cotton mealybug, Phenacoccus solenopsis (Tinsley) (Hemiptera: Pseudococcidae) and the numerical response of female predator. Experiments were carried out in controlled environment laboratory conditions at 25 ± 1 °C temperature, 60 ± 5% relative humidity and photoperiod of 16 h. Number of eggs consumed, number of eggs laid and the Efficiency of Conversion of Ingested food (ECI) were recorded daily. Results from the study revealed that all the developmental stages of S. coccivora exhibited a Type II response. Different parameters such as attack rate (a'), handling time (Th) and the maximum rate of predation were estimated using Roger's random attack equation and Holling Disc equation in which Rogers random attack equation was found best fit. Female has shown the highest attack rate (a') followed by IVth instar grub, male, IIIrd, IInd and Ist instar grub. With low handling time, IVth instar grub has shown maximum predation rate of 76.40 per day followed by female (75.86), male (58.79), IIIrd (22.84), IInd (19.65) and Ist instar grub (15.39). The numerical response increase was curvilinearly related to different prey densities with the highest number of eggs (11.8 ± 3.44) produced at highest prey density (160). The Efficiency of Conversion of Ingested food (ECI) was highest (64.49 ± 8.03) at prey density of 10. Understanding the factors that lead to variation in functional response of predator in natural population will advance our understanding of the effects of predation on individual and the effectiveness of coccinellid predators as biocontrol agent against cotton mealybug.
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Affiliation(s)
- Sweetee Kumari
- Biocontrol Laboratory, Division of Entomology, ICAR-IARI, Pusa, New Delhi 110012, India
| | - Sachin S Suroshe
- Biocontrol Laboratory, Division of Entomology, ICAR-IARI, Pusa, New Delhi 110012, India
| | - Dinesh Kumar
- Department of Zoology, Centre of Advanced Study, Institute of Science, BHU, Varanasi 221005, India
| | - Neeraj Budhlakoti
- Centre for Agricultural Bioinformatics, ICAR-IASRI, New Delhi 110012, India
| | - Venkanna Yana
- Biocontrol Laboratory, Division of Entomology, ICAR-IARI, Pusa, New Delhi 110012, India
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18
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Barraquand F, Gimenez O. Fitting stochastic predator-prey models using both population density and kill rate data. Theor Popul Biol 2021; 138:1-27. [PMID: 33515551 DOI: 10.1016/j.tpb.2021.01.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 11/23/2020] [Accepted: 01/14/2021] [Indexed: 12/01/2022]
Abstract
Most mechanistic predator-prey modelling has involved either parameterization from process rate data or inverse modelling. Here, we take a median road: we aim at identifying the potential benefits of combining datasets, when both population growth and predation processes are viewed as stochastic. We fit a discrete-time, stochastic predator-prey model of the Leslie type to simulated time series of densities and kill rate data. Our model has both environmental stochasticity in the growth rates and interaction stochasticity, i.e., a stochastic functional response. We examine what the kill rate data brings to the quality of the estimates, and whether estimation is possible (for various time series lengths) solely with time series of population counts or biomass data. Both Bayesian and frequentist estimation are performed, providing multiple ways to check model identifiability. The Fisher Information Matrix suggests that models with and without kill rate data are all identifiable, although correlations remain between parameters that belong to the same functional form. However, our results show that if the attractor is a fixed point in the absence of stochasticity, identifying parameters in practice requires kill rate data as a complement to the time series of population densities, due to the relatively flat likelihood. Only noisy limit cycle attractors can be identified directly from population count data (as in inverse modelling), although even in this case, adding kill rate data - including in small amounts - can make the estimates much more precise. Overall, we show that under process stochasticity in interaction rates, interaction data might be essential to obtain identifiable dynamical models for multiple species. These results may extend to other biotic interactions than predation, for which similar models combining interaction rates and population counts could be developed.
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Affiliation(s)
- Frédéric Barraquand
- CNRS, Institute of Mathematics of Bordeaux, France; University of Bordeaux, Integrative and Theoretical Ecology, LabEx COTE, France.
| | - Olivier Gimenez
- CNRS, Center for Evolutionary and Functional Ecology, Montpellier, France
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19
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Dai C, Ricupero M, Puglisi R, Lu Y, Desneux N, Biondi A, Zappalà L. Can contamination by major systemic insecticides affect the voracity of the harlequin ladybird? Chemosphere 2020; 256:126986. [PMID: 32445995 DOI: 10.1016/j.chemosphere.2020.126986] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 05/03/2020] [Accepted: 05/04/2020] [Indexed: 06/11/2023]
Abstract
Systemic neurotoxic insecticides are widely used to control aphid pests worldwide and their potential non-target effects on aphid predators are often unknown. Behavioral responses linked to biological control services are crucial when assessing the compatibility of chemicals with biocontrol organisms. This is particularly relevant for insecticides at low and sublethal concentrations. We studied the acute toxicity and the sublethal effect on the voracity of the generalist predator Harmonia axyridis (Coleoptera: Coccinellidae) caused by the exposure to three systemic insecticides routinely used against aphids. The tested insecticide concentrations were the Lethal Concentration 50% (LC50), 20% (LC20) and 1% (LC1) estimated for the target pest Aphis gossypii (Hemiptera: Aphididae) in a companion study. The survival and the voracity differed among the tested chemicals and concentrations, but only thiamethoxam at LC50 caused a significant predator mortality, and individuals that survived showed a reduced predation rate. The predators showed a density independent functional response after the exposure to most of the insecticide-concentration combinations, while an inverse density dependence of the prey consumption rate was observed for coccinellids exposed to sulfoxaflor and thiamethoxam at their lowest tested concentration. The estimated parameters, i.e., the attack rate and the prey handling time, were affected at higher concentrations by both imidacloprid and sulfoxaflor. These findings stress the importance of carefully evaluating side effects of insecticides at very low concentrations on beneficial arthropods in the risk assessment schemes for sustainable pest control programmes.
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Affiliation(s)
- Changchun Dai
- University of Catania, Department of Agriculture Food and Environment, Catania, Italy; Chinese Academy of Agricultural Sciences, Institute of Plant Protection, State Key Laboratory for Biology of Plant Diseases and Insect Pests, Beijing, 100193, China; Northeast Agricultural University, College of Agriculture, Department of Plant Protection, Harbin, 150030, China
| | - Michele Ricupero
- University of Catania, Department of Agriculture Food and Environment, Catania, Italy
| | - Roberto Puglisi
- University of Catania, Department of Agriculture Food and Environment, Catania, Italy
| | - Yanhui Lu
- Chinese Academy of Agricultural Sciences, Institute of Plant Protection, State Key Laboratory for Biology of Plant Diseases and Insect Pests, Beijing, 100193, China
| | - Nicolas Desneux
- Université Côte d'Azur, INRAE, CNRS, UMR ISA, 06000, Nice, France
| | - Antonio Biondi
- University of Catania, Department of Agriculture Food and Environment, Catania, Italy.
| | - Lucia Zappalà
- University of Catania, Department of Agriculture Food and Environment, Catania, Italy
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Rehman SU, Zhou X, Ali S, Asim Rasheed M, Islam Y, Hafeez M, Aamir Sohail M, Khurram H. Predatory functional response and fitness parameters of Orius strigicollis Poppius when fed Bemisia tabaci and Trialeurodes vaporariorum as determined by age-stage, two-sex life table. PeerJ 2020; 8:e9540. [PMID: 33194327 PMCID: PMC7394059 DOI: 10.7717/peerj.9540] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 06/23/2020] [Indexed: 11/20/2022] Open
Abstract
Background The polyphagous predatory bug O. strigicollis is an active predator used to control thrips and aphids. The whitefly species Bemisia tabaci and Trialeurodes vaporariorum are voracious pests of different economic agricultural crops and vegetables. Method In this study, the Holling disc equation and the age-stage, two-sex life table technique were used to investigate the functional response and biological traits of third instar nymphs and adult female O. strigicollis when presented third instar nymphs of both whitefly species as prey. Results The results showed a type II functional response for each life stage of O. strigicollis when fed each whitefly species. The calculated prey handling time for different O. strigicollis life stages were shorter when fed T. vaporariorum than when fed B. tabaci nymphs. In contrast, the nymphal development of O. strigicollis was significantly shorter when fed B. tabaci than T. vaporariorum nymphs. Additionally, the total pre-oviposition period of adult females was statistically shorter when fed B. tabaci nymphs than T. vaporariorum nymphs. Furthermore, the survival rates and total fecundity of O. strigicollis were higher when fed B. tabaci than T. vaporariorum. There were no significant differences in any population parameters of O. strigicollis when fed either whitefly species. These results show that O. strigicollis could survive and maintain its populations on both species of whitefly and could therefore serve as a biological control agent in integrated pest management (IPM).
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Affiliation(s)
- Shakeel Ur Rehman
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Xingmiao Zhou
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Shahzaib Ali
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Muhammad Asim Rasheed
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Yasir Islam
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Muhammad Hafeez
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Muhammad Aamir Sohail
- The Key Lab of Plant Pathology of Hubei Province, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Haris Khurram
- Department of Sciences and Humanities, National University of Computer and Emerging Sciences, Chiniot-Faisalabad Campus, Chiniot, Pakistan
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Emerick B, Singh A, Chhetri SR. Global redistribution and local migration in semi-discrete host-parasitoid population dynamic models. Math Biosci 2020; 327:108409. [PMID: 32615211 DOI: 10.1016/j.mbs.2020.108409] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 05/21/2020] [Accepted: 06/22/2020] [Indexed: 11/18/2022]
Abstract
Host-parasitoid population dynamics is often probed using a semi-discrete/hybrid modeling framework. Here, the update functions in the discrete-time model connecting year-to-year changes in the population densities are obtained by solving ordinary differential equations that mechanistically describe interactions when hosts become vulnerable to parasitoid attacks. We use this semi-discrete formalism to study two key spatial effects: local movement (migration) of parasitoids between patches during the vulnerable period; and yearly redistribution of populations across patches outside the vulnerable period. Our results show that in the absence of any redistribution, constant density-independent migration and parasitoid attack rates are unable to stabilize an otherwise unstable host-parasitoid population dynamics. Interestingly, inclusion of host redistribution (but not parasitoid redistribution) before the start of the vulnerable period can lead to stable coexistence of both species. Next, we consider a Type-III functional response (parasitoid attack rate increases with host density), where the absence of any spatial effects leads to a neutrally stable host-parasitoid equilibrium. As before, density-independent parasitoid migration by itself is again insufficient to stabilize the population dynamics and host redistribution provides a stabilizing influence. Finally, we show that a Type-III functional response combined with density-dependent parasitoid migration leads to stable coexistence, even in the absence of population redistributions. In summary, we have systematically characterized parameter regimes leading to stable/unstable population dynamics with different forms of spatial heterogeneity coupled to the parasitoid's functional response using mechanistically formulated semi-discrete models.
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Affiliation(s)
- Brooks Emerick
- Department of Mathematics, Kutztown University, Kutztown, PA 19530, United States of America.
| | - Abhyudai Singh
- Department of Electrical & Computer Engineering, University of Delaware, Newark, DE 19716, United States of America; Department of Biomedical Engineering, University of Delaware, Newark, DE, 19716, United States of America.
| | - Safal Raut Chhetri
- Department of Mathematics, Kutztown University, Kutztown, PA 19530, United States of America.
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Berardo C, Geritz S, Gyllenberg M, Raoul G. Interactions between different predator-prey states: a method for the derivation of the functional and numerical response. J Math Biol 2020; 80:2431-2468. [PMID: 32419034 PMCID: PMC7250814 DOI: 10.1007/s00285-020-01500-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 03/09/2020] [Indexed: 11/29/2022]
Abstract
In this paper we introduce a formal method for the derivation of a predator's functional response from a system of fast state transitions of the prey or predator on a time scale during which the total prey and predator densities remain constant. Such derivation permits an explicit interpretation of the structure and parameters of the functional response in terms of individual behaviour. The same method is also used here to derive the corresponding numerical response of the predator as well as of the prey.
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Affiliation(s)
- Cecilia Berardo
- Department of Mathematics and Statistics, University of Helsinki, 00014, Helsinki, Finland.
| | - Stefan Geritz
- Department of Mathematics and Statistics, University of Helsinki, 00014, Helsinki, Finland
| | - Mats Gyllenberg
- Department of Mathematics and Statistics, University of Helsinki, 00014, Helsinki, Finland
| | - Gaël Raoul
- Centre de Mathématiques Appliquées, École Polytechnique, 91128, Palaiseau Cedex, France
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Xia Z, Cao X, Hoxha T, Zhan A, Haffner GD, MacIsaac HJ. Functional response and size-selective clearance of suspended matter by an invasive mussel. Sci Total Environ 2020; 711:134679. [PMID: 31810685 DOI: 10.1016/j.scitotenv.2019.134679] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 06/25/2019] [Accepted: 09/25/2019] [Indexed: 06/10/2023]
Abstract
Filter feeding activities link suspension feeders with their environment and underpin their impact on aquatic ecosystems. Despite their ecological and economic impacts, the functional response and size-selective capture of suspended particulates have not been well documented for the golden mussel Limnoperna fortunei. Here we demonstrated that golden mussels had a type I functional response, with an attack rate a = 0.085 and negligible handling time (h). Clearance rate ranged between 72.6 ± 27.0 and 305.5 ± 105.9 mL ind.-1h-1 (Mean ± S.E.), depending on food concentrations, which exhibited an inverse relationship with clearance rate. Presence of golden mussels suppressed chlorophyll a concentration in experimental mesocosms, the extent of which was dependent on mussel abundance. Concentration of suspended particles in experimental mesocosms experienced a sharp initial decline across all size categories (≤1->50 μm), though with increased final concentration of large particles (>25 μm), indicating packaging and egestion by golden mussels of fine particles (down to ≤1 μm). Capture efficiency of quantitatively-dominant suspended matter (≤1-50 μm) by golden mussels was inversely related to particle size. Animal abundance, particle size, and their interaction (abundance × particle size) determined the extent to which matter was removed from the water column. Presently L. fortunei occurs primarily in the southern end of the central route of South to North Water Diversion Project (China), but the species is spreading north; we anticipate that impacts associated with filtering of L. fortunei will correspond with local population abundance along this gradient.
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Affiliation(s)
- Zhiqiang Xia
- Great Lakes Institute for Environmental Research, University of Windsor, Windsor, Ontario N9B 3P4, Canada; International S&T Collaborative Base for Water Environment Monitoring and Simulation in Three Gorges Reservoir Region, Chongqing 400715, China; Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
| | - Xinkai Cao
- Water Quality Monitoring Center of Beijing Waterworks Group Company Limited, Beijing 100192, China
| | - Tedi Hoxha
- Great Lakes Institute for Environmental Research, University of Windsor, Windsor, Ontario N9B 3P4, Canada
| | - Aibin Zhan
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - G Douglas Haffner
- Great Lakes Institute for Environmental Research, University of Windsor, Windsor, Ontario N9B 3P4, Canada; International S&T Collaborative Base for Water Environment Monitoring and Simulation in Three Gorges Reservoir Region, Chongqing 400715, China
| | - Hugh J MacIsaac
- Great Lakes Institute for Environmental Research, University of Windsor, Windsor, Ontario N9B 3P4, Canada; School of Ecology and Environmental Science, Yunnan University, Kunming 650091, China
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Masoero G, Laaksonen T, Morosinotto C, Korpimäki E. Age and sex differences in numerical responses, dietary shifts, and total responses of a generalist predator to population dynamics of main prey. Oecologia 2020; 192:699-711. [PMID: 32008080 DOI: 10.1007/s00442-020-04607-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 01/16/2020] [Indexed: 10/25/2022]
Abstract
Fluctuations in the abundance of main prey species might shape animal communities, by inducing numerical responses and dietary shifts in predators. Whether numerical responses and dietary shifts differ among individuals of different age and sex has so far gained little attention. These differences could affect how much predators consume main and alternative prey, thus causing variation in predation pressure on main and alternative prey species. We studied the effect of fluctuating main prey abundance (voles) in autumn on the age and sex composition of a food-hoarding population of Eurasian pygmy owls Glaucidium passerinum (327 individuals), and on the species composition of their food stores in western Finland during 2003-2017 (629 food stores). Numbers of yearlings (< 1-year old) of both sexes and adult (+ 1-year old) females increased with increasing vole abundance. During low vole abundance, adult owls stored more small birds and less small mammals than yearlings. Females stored more small mammals than males and showed a tendency to store less birds. The amount of consumed birds (the most important alternative prey), and in particular of crested, willow, great, and blue tits, increased with low vole densities. Our results show that numerical, functional, and total responses of pygmy owls, and probably also other vertebrate predators, to the availability of the main prey in winter are shaped by the age and sex composition of the predator population, which both show large spatio-temporal variation in boreal forests.
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Broom M, Cressman R, Křivan V. Revisiting the "fallacy of averages" in ecology: Expected gain per unit time equals expected gain divided by expected time. J Theor Biol 2019; 483:109993. [PMID: 31491495 DOI: 10.1016/j.jtbi.2019.109993] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 07/26/2019] [Accepted: 09/02/2019] [Indexed: 11/16/2022]
Abstract
Fitness is often defined as the average payoff an animal obtains when it is engaged in several activities, each taking some time. We point out that the average can be calculated with respect to either the time distribution, or to the event distribution of these activities. We show that these two averages lead to the same fitness function. We illustrate this result through two examples from foraging theory, Holling II functional response and the diet choice model, and one game-theoretic example of Hamilton's rule applied to the time-constrained Prisoner's dilemma (PD). In particular, we show that in these models, fitness defined as expected gain per unit time equals fitness defined as expected gain divided by expected time. We also show how these fitnesses predict the optimal outcome for diet choice and the prevalence of cooperation in the repeated PD game.
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Affiliation(s)
- Mark Broom
- Department of Mathematics, City, University of London, London, UK.
| | - Ross Cressman
- Department of Mathematics, Wilfrid Laurier University, Waterloo, Ontario, Canada.
| | - Vlastimil Křivan
- Department of Mathematics, Faculty of Science, University of South Bohemia, Branišovská 1760, České Budějovice 370 05, Czech Republic; Czech Academy of Sciences, Biology Centre, Institute of Entomology, Branišovská 31, České Budějovice 370 05, Czech Republic.
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Yang J, Löder MGJ, Jiang Y, Wiltshire KH. Are tintinnids picky grazers: Feeding experiments on a mixture of mixotrophic dinoflagellates and implications for red tide dynamics. Mar Pollut Bull 2019; 149:110488. [PMID: 31421564 DOI: 10.1016/j.marpolbul.2019.110488] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 07/31/2019] [Accepted: 07/31/2019] [Indexed: 06/10/2023]
Abstract
To understand and predict the outbreak of red tides, which are often dominated by mixotrophic dinoflagellates (MTDs), the effects of "top-down" control by co-occurring predators on red-tide MTDs should be taken into consideration. We studied the numerical and functional responses of the tintinnid ciliate Favella ehrenbergii feeding on two red-tide MTDs, Scrippsiella trochoidea and Heterocapsa triquetra, under single and mixed prey conditions. Our results suggest that a mixed diet could support a better growth of predators compared to a monodiet. In addition, the predators preferred to graze S. trochoidea in the mixed diets, suggesting that predators may switch their feeding preference. The grazing by tintinnid predators could potentially inhibit the outbreaks of red tides dominated by MTDs. The findings in this study provide basic data and new insights for understanding the complex predator-prey relationships in marine microbial food webs, and the dynamics of red tides dominated by MTDs.
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Affiliation(s)
- Jinpeng Yang
- School of Marine Sciences, Sun Yat-Sen University, Guangzhou 510006, China; Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519000, China; Biologische Anstalt Helgoland, Alfred Wegener Institute, Helmholtz Center for Polar and Marine Research, P.O. Box 180, Helgoland 27483, Germany.
| | - Martin Günter Joachim Löder
- Biologische Anstalt Helgoland, Alfred Wegener Institute, Helmholtz Center for Polar and Marine Research, P.O. Box 180, Helgoland 27483, Germany; Department of Animal Ecology I and BayCEER, University of Bayreuth, Universitätsstr. 30, Bayreuth 95440, Germany
| | - Yong Jiang
- College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China; Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao 266003, China.
| | - Karen Helen Wiltshire
- Biologische Anstalt Helgoland, Alfred Wegener Institute, Helmholtz Center for Polar and Marine Research, P.O. Box 180, Helgoland 27483, Germany
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Abstract
The aim of this paper is to conduct a systematic and theoretical analysis of estimation and inference for a class of functional mixed effects models (FMEM). Such FMEMs consist of fixed effects that characterize the association between longitudinal functional responses and covariates of interest and random effects that capture the spatial-temporal correlations of longitudinal functional responses. We propose local linear estimates of refined fixed effect functions and establish their weak convergence along with a simultaneous confidence band for each fixed-effect function. We propose a global test for the linear hypotheses of varying coefficient functions and derive the associated asymptotic distribution under the null hypothesis and the asymptotic power under the alternative hypothesis are derived. We also establish the convergence rates of the estimated spatial-temporal covariance operators and their associated eigenvalues and eigenfunctions. We conduct extensive simulations and apply our method to a white-matter fiber data set from a national database for autism research to examine the finite-sample performance of the proposed estimation and inference procedures.
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Affiliation(s)
- Hongtu Zhu
- The University of Texas MD Anderson Cancer Center
| | | | | | - Ying Yuan
- The University of Texas MD Anderson Cancer Center.,University of Pittsburgh.,Statistics & Decision Sciences.,University of California at Davis
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Bulai IM, Hilker FM. Eco-epidemiological interactions with predator interference and infection. Theor Popul Biol 2019; 130:191-202. [PMID: 31445973 DOI: 10.1016/j.tpb.2019.07.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 07/02/2019] [Accepted: 07/31/2019] [Indexed: 11/20/2022]
Abstract
Predator interference is a form of competition between predator individuals over access to their prey. There is broad empirical evidence for interference to exist in different strengths in various types of ecological communities. At the same time, parasites are increasingly recognized to alter food web structure and dynamics. In order to investigate the eco-epidemiological interplay between interference and infection, we develop and analyze mathematical models of a predator-prey system, where the predators are subject to both interference and infectious disease. In the absence of infection, equilibrium predator density is known to show a non-monotonic response to interference by first increasing and then decreasing with increasing interference levels. We show that predator infection can change this pattern into a monotonically decreasing predator response to interference, provided the transmissibility is large enough and the pathogenicity is moderate such that the impact of disease on host population density prevails over interference effects. This holds for both types of disease transmission studied here, density-dependent and frequency-dependent. For density-dependent transmission, we find that intermediate values of interference can facilitate disease persistence, whereas the disease would disappear for small or large interference levels. By contrast, for frequency-dependent transmission, disease emergence is independent of interference levels. These dynamic interactions may be important for the understanding of potential biocontrol measures and of spread patterns of zoonotic diseases.
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Viteri Jumbo LO, Teodoro AV, Rêgo AS, Haddi K, Galvão AS, de Oliveira EE. The lacewing Ceraeochrysa caligata as a potential biological agent for controlling the red palm mite Raoiella indica. PeerJ 2019; 7:e7123. [PMID: 31259098 PMCID: PMC6589328 DOI: 10.7717/peerj.7123] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 05/15/2019] [Indexed: 11/20/2022] Open
Abstract
Background Compared to chemical control, the use of naturally occurring biological agents to control invasive pests is less threatening to the environment and human health. Objectives Here, we assessed the ability of immature stages of the lacewing Ceraeochrysa caligata (Neuroptera: Chrysopidae) to prey upon different developmental stages of the red palm mite Raoiella indica (Acari: Tenuipalpidae), one of the most destructive invasive pests of palm trees in Neotropical regions. Methods Increasing densities of three stages of R. indica (eggs, immature stages, and adult females) were offered to C. caligata in coconut leaf arenas. The immature stages of C. caligata were less than 24 h old and were starved before being transferring to the arenas. The amount of prey consumed was recorded 6 h after releasing the C. caligata. Results Our results indicated that the ability of C. caligata to feed upon R. indica increased with the larval development of the predator. Higher feeding levels and shorter handling times were recorded for the first and second instars of C. caligata when preying upon the eggs and immature stages of R. indica. Furthermore, C. caligata individuals of different stages exhibited differential functional responses according to prey type (i.e., eggs, immatures, or adult females of R. indica). Ceraeochrysa caligata second instar individuals exhibited a sigmoid increase in consumption rate with increasing prey availability (i.e., a type III functional response) when preying upon immature stages of R. indica. However, when preying upon R. indica adult females, C. caligata second instar individuals exhibited a type II functional response (i.e., an increase in consumption rate with increasing prey availability, before reaching a plateau). Predator individuals of the first and third instar stages exhibited a type II functional response for all prey types. Conclusions Collectively, our findings demonstrate that C. caligata, especially at the second instar stage, has potential as a tool for ecological management of the red palm mite.
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Affiliation(s)
- Luis O Viteri Jumbo
- Departamento de Entomologia, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brasil.,Embrapa Tabuleiros Costeiros, Aracaju, Sergipe, Brasil
| | | | - Adriano S Rêgo
- Programa de Pós-Graduação em Agroecologia, Universidade Estadual do Maranhão, São Luís, Maranhão, Brasil
| | - Khalid Haddi
- Departamento de Entomologia, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brasil
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Bláha M, Grabicova K, Shaliutina O, Kubec J, Randák T, Zlabek V, Buřič M, Veselý L. Foraging behaviour of top predators mediated by pollution of psychoactive pharmaceuticals and effects on ecosystem stability. Sci Total Environ 2019; 662:655-661. [PMID: 30703723 DOI: 10.1016/j.scitotenv.2019.01.295] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Revised: 01/19/2019] [Accepted: 01/22/2019] [Indexed: 06/09/2023]
Abstract
Although pharmaceuticals are recognized as a major threat to aquatic ecosystems worldwide, little is known about their ecological effect on aquatic biota and ecosystems. Drug-induced behaviour changes could have a substantial impact on consumer-resource interactions influencing stability of the community and ecosystem. We combined laboratory experiments and functional response modelling to investigate effects of real wastewater treatment plant (WWTP) effluent, as well as environmentally relevant concentrations of the antidepressants citalopram and opioid pain medication tramadol, on trophic interactions. Our biological system consisted of dragonfly Aeshna cyanea larvae as predator of common carp Cyprinus carpio fry. Exposure to WWTP effluent significantly increased A. cyanea maximum feeding rate, while those parameters in tramadol and citalopram-exposed larvae were significantly lower from unexposed control group. This suggested the potential of all tested pollutants to have an effect on consumer-resource equilibrium in aquatic ecosystems. While WWTP effluent strengthened interaction strength (IS) of consumer-resource interaction dynamics making the food web more vulnerable to fluctuation and destabilization, tramadol and citalopram could inhibit the potential oscillations of the consumer-resource system by weakening the IS. Similar studies to reveal the potential of pervasive pharmaceuticals to change of consumer-resource interactions dynamics are needed, especially when real WWTP effluent consisting of mixture of various pharmaceuticals displayed very different effect from single compounds tested.
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Affiliation(s)
- Martin Bláha
- University of South Bohemia in České Budějovice, Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Zátiší 728/II, CZ-389 25 Vodňany, Czech Republic.
| | - Katerina Grabicova
- University of South Bohemia in České Budějovice, Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Zátiší 728/II, CZ-389 25 Vodňany, Czech Republic
| | - Olena Shaliutina
- University of South Bohemia in České Budějovice, Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Zátiší 728/II, CZ-389 25 Vodňany, Czech Republic
| | - Jan Kubec
- University of South Bohemia in České Budějovice, Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Zátiší 728/II, CZ-389 25 Vodňany, Czech Republic
| | - Tomáš Randák
- University of South Bohemia in České Budějovice, Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Zátiší 728/II, CZ-389 25 Vodňany, Czech Republic
| | - Vladimir Zlabek
- University of South Bohemia in České Budějovice, Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Zátiší 728/II, CZ-389 25 Vodňany, Czech Republic
| | - Miloš Buřič
- University of South Bohemia in České Budějovice, Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Zátiší 728/II, CZ-389 25 Vodňany, Czech Republic
| | - Lukáš Veselý
- University of South Bohemia in České Budějovice, Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Zátiší 728/II, CZ-389 25 Vodňany, Czech Republic
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31
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Yan J, Cui B, Huang H, O'Flynn S, Bai J, Ysebaert T. Functional consumers regulate the effect of availability of subsidy on trophic cascades in the Yellow River Delta, China. Mar Pollut Bull 2019; 140:157-164. [PMID: 30803629 DOI: 10.1016/j.marpolbul.2019.01.045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 01/22/2019] [Accepted: 01/22/2019] [Indexed: 06/09/2023]
Abstract
Understanding the environmental context where heterogeneous ecological processes affect biotic interactions is a key aim of ecological research. However, mechanisms underlying spatial variation in trophic interactions linked to resource availability across ecosystem gradients remains unclear. We experimentally manipulated the interactive effects of predator fish and quantitative gradient of leaf detritus on macroinvertebrates and benthic algae. We found that non-linear changes in the strength of trophic cascades were strongly linked to the retention rates of experimental leaf detritus and also determined by predatory consumers. Retention rate of leaf detritus influenced the recruitment of predatory invertebrates and foraging preference of predators, accounting for largely the variations in shift of strengthening and weakening trophic cascades. Our results highlight the importance to identify joint processes of recruitment and foraging responses of functional consumer in understanding the impacts of both anthropogenic and natural alterations in subsidy on trophic interaction of coastal food webs.
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Affiliation(s)
- Jiaguo Yan
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Beijing Normal University, Beijing 100875, China; NIOZ Royal Netherlands Institute for Sea Research, Department of Estuarine and Delta Systems, and Utrecht University, P.O. Box 140, 4400 AC Yerseke, the Netherlands
| | - Baoshan Cui
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Beijing Normal University, Beijing 100875, China.
| | - Honghui Huang
- Guangdong Provincial Key Laboratory of Fishery Ecology and Environment, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510300, China
| | - Sarah O'Flynn
- NIOZ Royal Netherlands Institute for Sea Research, Department of Estuarine and Delta Systems, and Utrecht University, P.O. Box 140, 4400 AC Yerseke, the Netherlands
| | - Junhong Bai
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Beijing Normal University, Beijing 100875, China
| | - Tom Ysebaert
- NIOZ Royal Netherlands Institute for Sea Research, Department of Estuarine and Delta Systems, and Utrecht University, P.O. Box 140, 4400 AC Yerseke, the Netherlands
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Cuthbert RN, Al-Jaibachi R, Dalu T, Dick JTA, Callaghan A. The influence of microplastics on trophic interaction strengths and oviposition preferences of dipterans. Sci Total Environ 2019; 651:2420-2423. [PMID: 30336431 DOI: 10.1016/j.scitotenv.2018.10.108] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 10/08/2018] [Accepted: 10/08/2018] [Indexed: 06/08/2023]
Abstract
Microplastic (MP) pollution continues to proliferate in freshwater, marine and terrestrial environments, but with their biotic implications remaining poorly understood. Biotic interactions such as predation can profoundly influence ecosystem structuring, stability and functioning. However, we currently lack quantitative understandings of how trophic interaction strengths and associated behaviours are influenced by MP pollution, and how transference of MPs between trophic levels relates to consumptive traits. We also lack understanding of key life-history effects of MPs, for example, reproductive strategies such as oviposition. The present study examines the predatory ability of non-biting midge larvae, Chaoborus flavicans, towards larvae of Culex pipiens mosquitoes when the latter are exposed to MPs, using a functional response (FR) approach. Transfer of MPs occurred from larval mosquitoes to larval midges via predation. Microplastics transfer was significantly positively related to predation rates. Predation by C. flavicans followed a Type II FR, with average maximum feeding rates of 6.2 mosquito larvae per hour. These and other FR parameters (attack rates and handling times) were not significantly influenced by the presence of MPs. Further, C. pipiens adults did not avoid ovipositing in habitats with high concentrations of MPs. We thus demonstrate that MPs can move readily through freshwater food webs via biotic processes such as predation, and that uptake correlates strongly with consumption rates. Further, as MPs do not deter adult mosquitoes from ovipositing, our experiments reveal high potential for MP exposure and transference through ecosystems.
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Affiliation(s)
- Ross N Cuthbert
- Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, Medical Biology Centre, Belfast BT9 7BL, Northern Ireland, United Kingdom; Ecology and Evolutionary Biology, School of Biological Sciences, University of Reading, Reading RG6 6AS, England, United Kingdom.
| | - Rana Al-Jaibachi
- Ecology and Evolutionary Biology, School of Biological Sciences, University of Reading, Reading RG6 6AS, England, United Kingdom
| | - Tatenda Dalu
- Department of Ecology and Resource Management, University of Venda, Thohoyandou 0950, South Africa; South African Institute for Aquatic Biodiversity (SAIAB), Grahamstown 6140, South Africa
| | - Jaimie T A Dick
- Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, Medical Biology Centre, Belfast BT9 7BL, Northern Ireland, United Kingdom
| | - Amanda Callaghan
- Ecology and Evolutionary Biology, School of Biological Sciences, University of Reading, Reading RG6 6AS, England, United Kingdom
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Jiang J, Zhang Z, Yu X, Yu C, Liu F, Mu W. Sublethal and transgenerational effects of thiamethoxam on the demographic fitness and predation performance of the seven-spot ladybeetle Coccinella septempunctata L. (Coleoptera: Coccinellidae). Chemosphere 2019; 216:168-178. [PMID: 30368081 DOI: 10.1016/j.chemosphere.2018.10.126] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 10/16/2018] [Accepted: 10/17/2018] [Indexed: 06/08/2023]
Abstract
Seven-spot ladybird beetles, Coccinella septempunctata L., are critical aphidophagous predators in the agricultural environment. Thiamethoxam, a neonicotinoid insecticide, is commonly used for controlling pests but impairs their natural enemies at the same time. To improve effective IPM (integrated pest management) strategies, we evaluated the sublethal and transgenerational effects of thiamethoxam on C. septempunctata. Our results showed that thiamethoxam at doses of 0.1 × LC10 (0.053 mg L-1) and LC10 (0.53 mg L-1) significantly reduced adult emergence, fecundity and fertility of the parental generation. In unexposed progeny (F1) of thiamethoxam-exposed parents, at the two doses 0.1 × LC10 and LC10, the larval stage was prolonged, and total longevity was decreased by 18.76 and 24.46%, respectively. The higher concentrations (0.1 × LC10 and LC10) also decreased the fecundity by 33.74 and 46.56%, respectively, and the oviposition period by 19.67 and 25.01%, respectively. In addition, demographic parameters including the intrinsic rate of increase (r), finite rate of increase (λ), net reproductive rate (R0), and mean generation time (T) were significantly reduced when exposed to LC10. Moreover, the predation activity of the F1 generation was reduced by the transgenerational effects of LC10. These results disclose negative influence of thiamethoxam at sublethal concentrations on this ladybird predator and its subsequent generation.
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Affiliation(s)
- Jiangong Jiang
- College of Plant Protection, Key Laboratory of Pesticide Toxicology & Application Technique, Shandong Agricultural University, Tai'an, Shandong 271018, China
| | - Zhengqun Zhang
- College of Horticulture Science and Engineering, Shandong Agricultural University, Tai'an, 271018, China
| | - Xin Yu
- Research Center of Pesticide Environmental Toxicology, Shandong Agricultural University, Tai'an, 271018 Shandong, PR China
| | - Caihong Yu
- College of Chemistry and Environment Engineering, China University of Mining and Technology (Beijing), 100083, Beijing, China
| | - Feng Liu
- College of Plant Protection, Key Laboratory of Pesticide Toxicology & Application Technique, Shandong Agricultural University, Tai'an, Shandong 271018, China
| | - Wei Mu
- College of Plant Protection, Key Laboratory of Pesticide Toxicology & Application Technique, Shandong Agricultural University, Tai'an, Shandong 271018, China.
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34
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Evans MJ, Hawley JE, Rego PW, Rittenhouse TAG. Hourly movement decisions indicate how a large carnivore inhabits developed landscapes. Oecologia 2018; 190:11-23. [PMID: 30506304 DOI: 10.1007/s00442-018-4307-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 11/16/2018] [Indexed: 12/01/2022]
Abstract
The ecology of wildlife living in proximity to humans often differs from that in more natural places. Animals may perceive anthropogenic features and people as threats, exhibiting avoidance behavior, or may acclimate to human activities. As development expands globally, changes in the ecology of species in response to human phenomena may determine whether animals persist in these changing environments. We hypothesize that American black bears (Ursus americanus) persist within developed areas by effectively avoiding risky landscape features. We test this by quantifying changes in the movements of adult females from a population living within exurban and suburban development. We collected hourly GPS data from 23 individuals from 2012 to 2014 and used step-selection functions to estimate selection for anthropogenic features. Females were more avoidant of roads and highways when with cubs than without and were more responsive to increased traffic volume. As bears occupied greater housing densities, selection for housing increased, while avoidance of roads and responsiveness to traffic increased. Behavioral flexibility allowed bears in highly developed areas to alter selection and avoidance for anthropogenic features seasonally. These findings support the hypothesis that black bears perceive human activity as risky, and effectively avoid these risks while inhabiting developed areas. We document a high amount of individual variation in selection of anthropogenic features within the study population. Our findings suggest that initially, wildlife can successfully inhabit developed landscapes by effectively avoiding human activity. However, variation among individuals provides the capacity for population-level shifts in behavior over time.
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Affiliation(s)
- Michael J Evans
- Department of Natural Resources and the Environment, University of Connecticut, Wildlife and Fisheries Conservation Center, Unit 4087, 1376 Storrs Rd., Storrs, CT, 06269, USA.
| | - Jason E Hawley
- Connecticut Department of Energy and Environmental Protection Wildlife Division, 341 Milford St., Burlington, CT, 06013, USA
| | - Paul W Rego
- Connecticut Department of Energy and Environmental Protection Wildlife Division, 341 Milford St., Burlington, CT, 06013, USA
| | - Tracy A G Rittenhouse
- Department of Natural Resources and the Environment, University of Connecticut, Wildlife and Fisheries Conservation Center, Unit 4087, 1376 Storrs Rd., Storrs, CT, 06269, USA
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35
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Höfer J, González HE, Laudien J, Schmidt GM, Häussermann V, Richter C. All you can eat: the functional response of the cold-water coral Desmophyllum dianthus feeding on krill and copepods. PeerJ 2018; 6:e5872. [PMID: 30416885 PMCID: PMC6223235 DOI: 10.7717/peerj.5872] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2018] [Accepted: 10/04/2018] [Indexed: 12/02/2022] Open
Abstract
The feeding behavior of the cosmopolitan cold-water coral (CWC) Desmophyllum dianthus (Cnidaria: Scleractinia) is still poorly known. Its usual deep distribution restricts direct observations, and manipulative experiments are so far limited to prey that do not occur in CWC natural habitat. During a series of replicated incubations, we assessed the functional response of this coral feeding on a medium-sized copepod (Calanoides patagoniensis) and a large euphausiid (Euphausia vallentini). Corals showed a Type I functional response, where feeding rate increased linearly with prey abundance, as predicted for a tentaculate passive suspension feeder. No significant differences in feeding were found between prey items, and corals were able to attain a maximum feeding rate of 10.99 mg C h−1, which represents an ingestion of the 11.4% of the coral carbon biomass per hour. These findings suggest that D. dianthus is a generalist zooplankton predator capable of exploiting dense aggregations of zooplankton over a wide prey size-range.
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Affiliation(s)
- Juan Höfer
- Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile, Valdivia, Chile.,Centro FONDAP de Investigación en Dinámica de Ecosistemas Marinos de Altas Latitudes (IDEAL), Valdivia, Chile
| | - Humberto E González
- Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile, Valdivia, Chile.,Centro FONDAP de Investigación en Dinámica de Ecosistemas Marinos de Altas Latitudes (IDEAL), Valdivia, Chile
| | - Jürgen Laudien
- Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar und Meeresforschung, Bremerhaven, Germany
| | - Gertraud M Schmidt
- Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar und Meeresforschung, Bremerhaven, Germany
| | - Verena Häussermann
- Facultad de Recursos Naturales, Escuela de Ciencias del Mar, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile.,Huinay Scientific Field Station, Huinay, Chile
| | - Claudio Richter
- Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar und Meeresforschung, Bremerhaven, Germany.,Fachbereich Biologie/Chemie, Universität Bremen, Bremen, Germany
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36
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Thorp CJ, Alexander ME, Vonesh JR, Measey J. Size-dependent functional response of Xenopus laevis feeding on mosquito larvae. PeerJ 2018; 6:e5813. [PMID: 30386704 PMCID: PMC6204824 DOI: 10.7717/peerj.5813] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Accepted: 09/21/2018] [Indexed: 11/29/2022] Open
Abstract
Predators can play an important role in regulating prey abundance and diversity, determining food web structure and function, and contributing to important ecosystem services, including the regulation of agricultural pests and disease vectors. Thus, the ability to predict predator impact on prey is an important goal in ecology. Often, predators of the same species are assumed to be functionally equivalent, despite considerable individual variation in predator traits known to be important for shaping predator–prey interactions, like body size. This assumption may greatly oversimplify our understanding of within-species functional diversity and undermine our ability to predict predator effects on prey. Here, we examine the degree to which predator–prey interactions are functionally homogenous across a natural range of predator body sizes. Specifically, we quantify the size-dependence of the functional response of African clawed frogs (Xenopus laevis) preying on mosquito larvae (Culex pipiens). Three size classes of predators, small (15–30 mm snout-vent length), medium (50–60 mm) and large (105–120 mm), were presented with five densities of prey to determine functional response type and to estimate search efficiency and handling time parameters generated from the models. The results of mesocosm experiments showed that type of functional response of X. laevis changed with size: small predators exhibited a Type II response, while medium and large predators exhibited Type III responses. Functional response data showed an inversely proportional relationship between predator attack rate and predator size. Small and medium predators had highest and lowest handling time, respectively. The change in functional response with the size of predator suggests that predators with overlapping cohorts may have a dynamic impact on prey populations. Therefore, predicting the functional response of a single size-matched predator in an experiment may misrepresent the predator’s potential impact on a prey population.
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Affiliation(s)
- Corey J Thorp
- Centre for Invasion Biology, Department of Botany & Zoology, Stellenbosch University, Stellenbosch, South Africa
| | - Mhairi E Alexander
- Centre for Invasion Biology, Department of Botany & Zoology, Stellenbosch University, Stellenbosch, South Africa.,Institute for Biomedical and Environmental Health Research (IBEHR), School of Health and Life Sciences, University of the West of Scotland, Paisley, UK
| | - James R Vonesh
- Centre for Invasion Biology, Department of Botany & Zoology, Stellenbosch University, Stellenbosch, South Africa.,Department of Biology, Virginia Commonwealth University, Richmond, VA, USA.,Center for Environmental Studies, Virginia Commonwealth University, Richmond, VA, USA
| | - John Measey
- Centre for Invasion Biology, Department of Botany & Zoology, Stellenbosch University, Stellenbosch, South Africa
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37
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Hoxha T, Crookes S, Lejeusne C, Dick JTA, Chang X, Bouchemousse S, Cuthbert RN, MacIsaac HJ. Comparative feeding rates of native and invasive ascidians. Mar Pollut Bull 2018; 135:1067-1071. [PMID: 30301002 DOI: 10.1016/j.marpolbul.2018.08.039] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 08/17/2018] [Accepted: 08/19/2018] [Indexed: 06/08/2023]
Abstract
Ascidians have a recent history of species introductions globally, often with strong ecological impacts. Comparisons of per capita effects of invaders and comparable natives are useful to assess such impacts. Here, we explore ingestion rates (IR) and clearance rates (CR) of Ciona intestinalis and Ciona robusta, co-occurring native and non-native ascidians, respectively, from Brittany, France. IR was positively related to food concentration, with the invader responding more strongly to increasing food concentration. CR also differed by species, with the invader demonstrating higher values. C. robusta exhibited a higher functional response (Type I) than did C. intestinalis (Type II). Relative impact measured using seasonal abundance and IR revealed that C. robusta has a much greater impact than C. intestinalis at all food concentrations tested, though the former has a constrained distribution which limits its regional impact. Nevertheless, when abundant, we expect C. robusta to exert a greater impact on algal foods.
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Affiliation(s)
- Tedi Hoxha
- Great Lakes Institute for Environmental Research, University of Windsor, Windsor, Ontario N9B 3P4, Canada
| | - Steve Crookes
- Great Lakes Institute for Environmental Research, University of Windsor, Windsor, Ontario N9B 3P4, Canada; Biodiversity Institute of Ontario, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Christophe Lejeusne
- Sorbonne Université, CNRS, UMR 7144 AD2M, Station Biologique de Roscoff, Place Georges Teissier, 29680 Roscoff, France
| | - Jaimie T A Dick
- Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, Belfast, Northern Ireland BT9 7BL, UK
| | - Xuexiu Chang
- School of Ecology and Environmental Sciences, Yunnan University, Kunming 650091, China
| | - Sarah Bouchemousse
- Sorbonne Université, CNRS, UMR 7144 AD2M, Station Biologique de Roscoff, Place Georges Teissier, 29680 Roscoff, France; Department of Biology, University of Fribourg, Chemin du musée 10, 1700 Fribourg, Switzerland
| | - Ross N Cuthbert
- Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, Belfast, Northern Ireland BT9 7BL, UK
| | - Hugh J MacIsaac
- Great Lakes Institute for Environmental Research, University of Windsor, Windsor, Ontario N9B 3P4, Canada; School of Ecology and Environmental Sciences, Yunnan University, Kunming 650091, China.
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38
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Wasserman RJ, Cuthbert RN, Alexander ME, Dalu T. Shifting interaction strength between estuarine mysid species across a temperature gradient. Mar Environ Res 2018; 140:390-393. [PMID: 30054133 DOI: 10.1016/j.marenvres.2018.07.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 06/26/2018] [Accepted: 07/20/2018] [Indexed: 06/08/2023]
Abstract
In many coastal regions, mean coastal atmospheric and water temperatures are projected to shift as climate change ensues. Interaction strengths between organisms are likely to change along with environmental changes, given interspecific heterogeneity in responses to physico-chemical variables. Biological interaction outcomes have the potential to alter food web production and trophic level biomass distribution. This is particularly pertinent for key species that are either abundant or play disproportionately large roles in ecosystem processes. Using a functional response approach, we quantified the effects of shifting temperatures on interactions between key mysid species-sympatric in their distribution across a biogeographic transition zone along the east coast of South Africa. The Rhopalophthalmus terranatalis functional response type toward Mesopodopsis wooldridgei prey was independent of temperature, with all treatments producing Type II functional responses. Temperature effects on predator-prey dynamics were, however, evident as interaction strength was greatest at 21 °C, as measured by maximum feeding rates. Unlike maximum feeding rate, attack rates increased linearly with increasing temperature across the experimental treatments. Our findings suggest that interaction strength between the mysid shrimp species is likely to vary spatially along the current length of their sympatric distribution and temporally in certain regions where temperatures are projected to change. Such experimental interaction investigations are becoming increasingly important given our relatively poor understanding of the consequences of environmental change for effects on interactions among species and their wider ecosystem implications.
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Affiliation(s)
- Ryan J Wasserman
- Department of Biological Sciences and Biotechnology, Botswana International University of Science and Technology, P. Bag 16, Palapye, Botswana; South African Institute for Aquatic Biodiversity (SAIAB), P. Bag 1015, Grahamstown, 6140, South Africa.
| | - Ross N Cuthbert
- Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, Belfast, BT9 7BL, Northern Ireland, United Kingdom
| | - Mhairi E Alexander
- Institute for Biomedical and Environmental Health Research, School of Science and Sport, University of the West of Scotland, Paisley, Scotland, United Kingdom
| | - Tatenda Dalu
- Department of Ecology and Resource Management, University of Venda, Thohoyandou, 0950, South Africa
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Kruff N, Lax C, Liebscher V, Walcher S. The Rosenzweig-MacArthur system via reduction of an individual based model. J Math Biol 2018; 78:413-439. [PMID: 30094616 DOI: 10.1007/s00285-018-1278-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 07/31/2018] [Indexed: 10/28/2022]
Abstract
The Rosenzweig-MacArthur system is a particular case of the Gause model, which is widely used to describe predator-prey systems. In the classical derivation, the interaction terms in the differential equation are essentially derived from considering handling time vs. search time, and moreover there exist derivations in the literature which are based on quasi-steady state assumptions. In the present paper we introduce a derivation of this model from first principles and singular perturbation reductions. We first establish a simple stochastic mass action model which leads to a three-dimensional ordinary differential equation, and systematically determine all possible singular perturbation reductions (in the sense of Tikhonov and Fenichel) to two-dimensional systems. Among the reductions obtained we find the Rosenzweig-MacArthur system for a certain choice of small parameters as well as an alternative to the Rosenzweig-MacArthur model, with density dependent death rates for predators. The arguments to obtain the reductions are intrinsically mathematical; no heuristics are employed.
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Affiliation(s)
- Niclas Kruff
- Lehrstuhl A für Mathematik, RWTH Aachen University, 52056, Aachen, Germany
| | - Christian Lax
- Lehrstuhl A für Mathematik, RWTH Aachen University, 52056, Aachen, Germany
| | - Volkmar Liebscher
- Institute of Mathematics and Computer Science, University Greifswald, 17487, Greifswald, Germany.
| | - Sebastian Walcher
- Lehrstuhl A für Mathematik, RWTH Aachen University, 52056, Aachen, Germany
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40
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Paris-Garcia F, Barroso A, Paris F. A study of the reproducibility and reliability of the musculo-articular stiffness of the ankle joint. J Mech Behav Biomed Mater 2018; 82:145-153. [PMID: 29601986 DOI: 10.1016/j.jmbbm.2018.03.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 03/05/2018] [Accepted: 03/14/2018] [Indexed: 11/18/2022]
Abstract
The objective of this work was to evaluate the reproducibility, reliability and usefulness of the musculo-articular stiffness (MAS) of the ankle joint, measuring it by the free vibration technique. Seventeen (nine males and eight females) healthy university students were included in the study. Force (f), MAS (k) and unitary MAS (ku) (defined as the ratio between the value of stiffness k obtained in the test (absolute terms) and the value of force (f)) were obtained. A test-retest protocol was designed and performed on the same day to determine the short-term reproducibility of f, k and ku. Short-term reproducibility of k and ku on 1 day in absolute terms (< 7% Coefficient of Variation (CV)) and relative reproducibility (Intraclass Correlation Coefficient (ICC) and Pearson ≥ 0.97) for both feet were obtained. The reliability of k and ku in absolute terms (< 9% CV) and in relative terms (ICC and Pearson ≥0.93) based on repeating the protocol for 1 week was analysed for both feet. To analyse the usefulness, the Effect Size (ES) ratio = "Trivial" for all variables (for 1 day and 1 week) and the Smallest Worthwhile Change (SWC) ratio (Typical Error (TE)< SWC) = "GOOD" for k and ku (1 day and 1 week) were considered. The Minimal Difference needed to be considered "real" (MD) for ku ≅ 3.5% (1 day); ku≅ 8.5% (1 week) (p < 0.05) was obtained. The statistical analysis carried out displayed the high reproducibility, reliability and usefulness of the MAS test, which was more consistent with ku than k. Therefore, the unitary stiffness (ku) proven to be representative of the mechanical response of the ankle joint obtained by free vibration techniques, which allows comparison between different subjects.
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Affiliation(s)
| | - Alberto Barroso
- School of Engineering, University of Seville, Seville, Spain
| | - Federico Paris
- School of Engineering, University of Seville, Seville, Spain
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Greenspoon PB, Banton S, Mideo N. Immune system handling time may alter the outcome of competition between pathogens and the immune system. J Theor Biol 2018; 447:25-31. [PMID: 29555432 DOI: 10.1016/j.jtbi.2018.03.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 03/09/2018] [Indexed: 11/21/2022]
Abstract
Predators may be limited in their ability to kill prey (i.e., have type II or III functional responses), an insight that has had far-reaching consequences in the ecological literature. With few exceptions, however, this possibility has not been extended to the behaviour of immune cells, which kill pathogens much as predators kill their prey. Rather, models of the within-host environment have tended to tacitly assume that immune cells have an unlimited ability to target and kill pathogens (i.e., a type I functional response). Here we explore the effects of changing this assumption on infection outcomes (i.e., pathogen loads). We incorporate immune cell handling time into an ecological model of the within-host environment that considers both the predatory nature of the pathogen-immune cell interaction as well as competition between immune cells and pathogens for host resources. Unless pathogens can preempt immune cells for host resources, adding an immune cell handling time increases equilibrium pathogen load. We find that the shape of the relationship between energy intake and pathogen load can change: with a type I functional response, pathogen load is maximised at intermediate inputs, while for a type II or III functional response, pathogen load is solely increasing. With a type II functional response, pathogen load can fluctuate rather than settling to an equilibrium, a phenomenon unobserved with type I or III functional responses. Our work adds to a growing literature highlighting the role of resource availability in host-parasite interactions. Implications of our results for adaptive anorexia are discussed.
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42
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Aldebert C, Kooi BW, Nerini D, Poggiale JC. Is structural sensitivity a problem of oversimplified biological models? Insights from nested Dynamic Energy Budget models. J Theor Biol 2018; 448:1-8. [PMID: 29550453 DOI: 10.1016/j.jtbi.2018.03.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 03/01/2018] [Accepted: 03/13/2018] [Indexed: 10/17/2022]
Abstract
Many current issues in ecology require predictions made by mathematical models, which are built on somewhat arbitrary choices. Their consequences are quantified by sensitivity analysis to quantify how changes in model parameters propagate into an uncertainty in model predictions. An extension called structural sensitivity analysis deals with changes in the mathematical description of complex processes like predation. Such processes are described at the population scale by a specific mathematical function taken among similar ones, a choice that can strongly drive model predictions. However, it has only been studied in simple theoretical models. Here, we ask whether structural sensitivity is a problem of oversimplified models. We found in predator-prey models describing chemostat experiments that these models are less structurally sensitive to the choice of a specific functional response if they include mass balance resource dynamics and individual maintenance. Neglecting these processes in an ecological model (for instance by using the well-known logistic growth equation) is not only an inappropriate description of the ecological system, but also a source of more uncertain predictions.
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Affiliation(s)
- Clement Aldebert
- Mediterranean Institute of Oceanography, Aix-Marseille University, Toulon University, CNRS/INSU,IRD, MIO, UM 110, Marseille, Cedex 09 13288, France; University of Zurich, Institute of Evolutionary Biology and Environmental Studies, Winterthurerstrasse 190, Zurich 8057, Switzerland.
| | - Bob W Kooi
- Faculty of Science, VU University, de Boelelaan 1085,HV Amsterdam 1081, The Netherlands
| | - David Nerini
- Mediterranean Institute of Oceanography, Aix-Marseille University, Toulon University, CNRS/INSU,IRD, MIO, UM 110, Marseille, Cedex 09 13288, France.
| | - Jean-Christophe Poggiale
- Mediterranean Institute of Oceanography, Aix-Marseille University, Toulon University, CNRS/INSU,IRD, MIO, UM 110, Marseille, Cedex 09 13288, France.
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Seo G, Wolkowicz GSK. Sensitivity of the dynamics of the general Rosenzweig-MacArthur model to the mathematical form of the functional response: a bifurcation theory approach. J Math Biol 2018; 76:1873-1906. [PMID: 29307085 DOI: 10.1007/s00285-017-1201-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 12/26/2017] [Indexed: 11/26/2022]
Abstract
The equations in the Rosenzweig-MacArthur predator-prey model have been shown to be sensitive to the mathematical form used to model the predator response function even if the forms used have the same basic shape: zero at zero, monotone increasing, concave down, and saturating. Here, we revisit this model to help explain this sensitivity in the case of three response functions of Holling type II form: Monod, Ivlev, and Hyperbolic tangent. We consider both the local and global dynamics and determine the possible bifurcations with respect to variation of the carrying capacity of the prey, a measure of the enrichment of the environment. We give an analytic expression that determines the criticality of the Hopf bifurcation, and prove that although all three forms can give rise to supercritical Hopf bifurcations, only the Trigonometric form can also give rise to subcritical Hopf bifurcation and has a saddle node bifurcation of periodic orbits giving rise to two coexisting limit cycles, providing a counterexample to a conjecture of Kooji and Zegeling. We also revisit the ranking of the functional responses, according to their potential to destabilize the dynamics of the model and show that given data, not only the choice of the functional form, but the choice of the number and/or position of the data points can influence the dynamics predicted.
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Affiliation(s)
- Gunog Seo
- Department of Mathematics, Colgate University, 13 Oak Drive, Hamilton, NY, 13346, USA.
| | - Gail S K Wolkowicz
- Department of Mathematics and Statistics, McMaster University, 1280 Main Street West, Hamilton, ON, L8S 4K1, Canada
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Zubrod JP, Bundschuh R, Englert D, Rohrberg M, Wieczorek MV, Bakanov N, Schulz R, Bundschuh M. Transient effects following peak exposures towards pesticides - An explanation for the unresponsiveness of in situ measured functional variables. Environ Pollut 2017; 231:1393-1397. [PMID: 28923344 DOI: 10.1016/j.envpol.2017.08.121] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 08/18/2017] [Accepted: 08/30/2017] [Indexed: 06/07/2023]
Abstract
Invertebrate-mediated leaf litter decomposition is frequently used to assess stress-related implications in stream ecosystem integrity. In situ measures such as the mass loss from leaf bags or the feeding of caged invertebrates deployed for days or weeks may, however, fail to detect transient effects due to recovery or compensatory mechanisms. We assessed the relevance of transient effects using the peak exposure towards an insecticide (i.e., etofenprox) as a model scenario at three levels of complexity. These were 1) the assessment of the decomposition realised by invertebrate communities in stream mesocosms over 21 days via leaf bags, 2) 7-days lasting in situ bioassays quantifying the leaf consumption of Gammarus fossarum, and 3) a laboratory experiment determining the daily feeding rate of the same species over 7 days. Etofenprox did not trigger a significantly altered decomposition by invertebrate communities during the leaf bag assay, while in situ bioassays detected a significant reduction in gammarids' feeding rate at the highest tested concentration. The laboratory bioassay suggests that observed mismatches might be explained by recovery and post-exposure compensation. As leaf-shredding invertebrates are likely in a vulnerable state following transient effects, biomonitoring for implications of peak exposures and other pulsed stress events must happen at an adequate temporal resolution.
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Affiliation(s)
- Jochen P Zubrod
- Institute for Environmental Sciences, University of Koblenz-Landau, Fortstraße 7, 76829 Landau, Germany; Eusserthal Ecosystem Research Station, University of Koblenz-Landau, Birkenthalstrasse 13, 76857 Eusserthal, Germany.
| | - Rebecca Bundschuh
- Institute for Environmental Sciences, University of Koblenz-Landau, Fortstraße 7, 76829 Landau, Germany
| | - Dominic Englert
- Institute for Environmental Sciences, University of Koblenz-Landau, Fortstraße 7, 76829 Landau, Germany
| | - Markus Rohrberg
- Institute for Environmental Sciences, University of Koblenz-Landau, Fortstraße 7, 76829 Landau, Germany
| | - Matthias V Wieczorek
- Institute for Environmental Sciences, University of Koblenz-Landau, Fortstraße 7, 76829 Landau, Germany
| | - Nikita Bakanov
- Institute for Environmental Sciences, University of Koblenz-Landau, Fortstraße 7, 76829 Landau, Germany
| | - Ralf Schulz
- Institute for Environmental Sciences, University of Koblenz-Landau, Fortstraße 7, 76829 Landau, Germany
| | - Mirco Bundschuh
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Lennart Hjelms Väg 9, 75007 Uppsala, Sweden
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Abstract
We investigated how recent changes in the distribution and abundance of a fouling organism affected the strength of interactions between a commercially important foundation species and a common predator. Increases in the abundance of boring sponges that bioerode the calcified shells of oysters and other shelled organisms have been attributed to increased salinization of estuarine ecosystems. We tested the hypothesis that fouling by boring sponges will change the interaction strength between oysters and a common predator (stone crabs). We generated five oyster density treatments crossed with two sponge treatments (sponge and no sponge). We contrasted the interaction strength between stone crabs and fouled and non-fouled oysters by comparing the parameters of fitted functional response curves based on Rogers random predation model. We found that fouled oysters suffered higher predation from stone crabs, and that the increased predation risk stemmed from a reduction in the handling time needed to consume the fouled oysters. These findings highlight the importance of understanding the effects of abiotic changes on both the composition of ecological communities, and on the strengths of direct and indirect interactions among species. Global climate change is altering local ecosystems in complex ways, and the success of restoration, management, and mitigation strategies for important species requires a better appreciation for how these effects cascade through ecosystems.
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Affiliation(s)
- Cori J Speights
- Department of Biological Sciences, Mississippi State University, Starkville, MS, United States of America.,Department of Biology, East Carolina University, Greenville, NC, United States of America
| | - Michael W McCoy
- Department of Biology, East Carolina University, Greenville, NC, United States of America
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Mesgaran MB, Bouhours J, Lewis MA, Cousens RD. How to be a good neighbour: Facilitation and competition between two co-flowering species. J Theor Biol 2017; 422:72-83. [PMID: 28419864 DOI: 10.1016/j.jtbi.2017.04.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2016] [Revised: 04/09/2017] [Accepted: 04/10/2017] [Indexed: 11/29/2022]
Abstract
Empirical evidence suggests that co-flowering species can facilitate each other through shared pollinators. However, the extent to which one co-flowering species can relieve pollination limitation of another while simultaneously competing for abiotic resource has rarely been examined. Using a deterministic model we explored the demographic outcome for one ("focal") species of its co-occurrence with a species that shares pollinators and competes for both pollinator visitation and abiotic resources. In this paper we showed how the overall impact can be positive or negative, depending on the balance between enhanced fertilization versus increased competition. Our model could predict the density of co-flowering species that will maximize the pollination rate of the focal species by attracting pollinators. Because that density will also give rise to competitive effects, a lower density of co-flowering species is required for optimizing the trade-off between enhanced fertilization and competition so as to give the maximum possible facilitation of reproduction in the focal species. Results were qualitatively different when we considered attractiveness of the co-flowering species, as opposed to its density, because attractiveness, unlike density, had no effect on competition for abiotic resources. Whereas unattractive neighbours would not bring in pollinators, very attractive neighbours would captivate pollinators, not sharing them with the focal species. Thus optimal benefit to the focal species came at intermediate levels of attractiveness in the co-flowering species. This intermediate level of attractiveness in co-flowering species simultaneously maximized pollination and overall facilitation of reproduction for the focal species. The likelihood of facilitation was predicted to decline with the selfing rate of the focal species, revealing an indirect cost for an inbreeding mating system. Whether a co-flowering species can be facilitative depends on the way pollinators respond to the plant density: only a Type III functional response for visitation rate can result in facilitation. Our model provided both a conceptual framework and precise quantitative measures for determining the impacts of a neighbouring co-flowering species on reproduction.
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Affiliation(s)
- Mohsen B Mesgaran
- School of BioSciences, The University of Melbourne, Victoria 3010, Australia.
| | - Juliette Bouhours
- Department of Mathematical and Statistical Sciences, University of Alberta, Alberta, T6G 2G1 Canada
| | - Mark A Lewis
- Department of Mathematical and Statistical Sciences, University of Alberta, Alberta, T6G 2G1 Canada; Department of Biological Sciences, University of Alberta, Alberta, T6G2G1, Canada
| | - Roger D Cousens
- School of BioSciences, The University of Melbourne, Victoria 3010, Australia.
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Li Y, Brose U, Meyer K, Rall BC. How patch size and refuge availability change interaction strength and population dynamics: a combined individual- and population-based modeling experiment. PeerJ 2017; 5:e2993. [PMID: 28243529 PMCID: PMC5322756 DOI: 10.7717/peerj.2993] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 01/15/2017] [Indexed: 12/25/2022] Open
Abstract
Knowledge on how functional responses (a measurement of feeding interaction strength) are affected by patch size and habitat complexity (represented by refuge availability) is crucial for understanding food-web stability and subsequently biodiversity. Due to their laborious character, it is almost impossible to carry out systematic empirical experiments on functional responses across wide gradients of patch sizes and refuge availabilities. Here we overcame this issue by using an individual-based model (IBM) to simulate feeding experiments. The model is based on empirically measured traits such as body-mass dependent speed and capture success. We simulated these experiments in patches ranging from sizes of petri dishes to natural patches in the field. Moreover, we varied the refuge availability within the patch independently of patch size, allowing for independent analyses of both variables. The maximum feeding rate (the maximum number of prey a predator can consume in a given time frame) is independent of patch size and refuge availability, as it is the physiological upper limit of feeding rates. Moreover, the results of these simulations revealed that a type III functional response, which is known to have a stabilizing effect on population dynamics, fitted the data best. The half saturation density (the prey density where a predator consumes half of its maximum feeding rate) increased with refuge availability but was only marginally influenced by patch size. Subsequently, we investigated how patch size and refuge availability influenced stability and coexistence of predator-prey systems. Following common practice, we used an allometric scaled Rosenzweig–MacArthur predator-prey model based on results from our in silico IBM experiments. The results suggested that densities of both populations are nearly constant across the range of patch sizes simulated, resulting from the constant interaction strength across the patch sizes. However, constant densities with decreasing patch sizes mean a decrease of absolute number of individuals, consequently leading to extinction of predators in the smallest patches. Moreover, increasing refuge availabilities also allowed predator and prey to coexist by decreased interaction strengths. Our results underline the need for protecting large patches with high habitat complexity to sustain biodiversity.
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Affiliation(s)
- Yuanheng Li
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany; Institute of Ecology, Friedrich-Schiller Universität Jena, Jena, Germany; Johann-Friedrich-Blumenbach Institute of Zoology and Anthropology, Georg-August-Universität Göttingen, Göttingen, Germany
| | - Ulrich Brose
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany; Institute of Ecology, Friedrich-Schiller Universität Jena, Jena, Germany
| | - Katrin Meyer
- Department of Ecosystem Modelling, Georg-August-Universität Göttingen , Göttingen , Germany
| | - Björn C Rall
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany; Institute of Ecology, Friedrich-Schiller Universität Jena, Jena, Germany
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Mondal RP, Chandra G, Bandyopadhyay S, Ghosh A. Effect of temperature and search area on the functional response of Anisops sardea (Hemiptera: Notonectidae) against Anopheles stephensi in laboratory bioassay. Acta Trop 2017; 166:262-267. [PMID: 27908745 DOI: 10.1016/j.actatropica.2016.11.034] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 11/18/2016] [Accepted: 11/27/2016] [Indexed: 11/15/2022]
Abstract
Present study was carried out to establish the influence of abiotic factors on foraging activities of a predatory hemipteran insect Anisops sardea against Anopheles stephensi larvae. The functional response of A. sardea was evaluated in variable density of prey items with variation in search area (100, 250, 500 and 1000ml water volume) and temperatures (20, 25 and 30°C). The results of laboratory bioassay revealed that prey consumption rate of predator species was positively related with increasing temperature and inversely related with increasing search area. Polynomial logistic regression equations and associated parameters showed that A. sardea exhibited a type II functional response in variable search area and type-III response at variable temperatures. Related response specific attack rates and handling times were also evaluated in presence of specific abiotic factors.
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Affiliation(s)
| | - Goutam Chandra
- Mosquito and Microbiology Research Units, The University of Burdwan, West Bengal, India
| | | | - Anupam Ghosh
- Department of Zoology, Bankura Christian College, West Bengal, India.
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Quinn TP, Cunningham CJ, Wirsing AJ. Diverse foraging opportunities drive the functional response of local and landscape-scale bear predation on Pacific salmon. Oecologia 2016; 183:415-429. [PMID: 27873066 DOI: 10.1007/s00442-016-3782-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Accepted: 11/15/2016] [Indexed: 11/27/2022]
Abstract
The relationship between prey abundance and predation is often examined in single habitat units or populations, but predators may occupy landscapes with diverse habitats and foraging opportunities. The vulnerability of prey within populations may depend on habitat features that hinder predation, and increased density of conspecifics in both the immediate vicinity and the broader landscape. We evaluated the relative effects of physical habitat, local, and neighborhood prey density on predation by brown bears on sockeye salmon in a suite of 27 streams using hierarchical Bayesian functional response models. Stream depth and width were inversely related to the maximum proportion of salmon killed, but not the asymptotic limit on total number killed. Interannual variation in predation was density dependent; the number of salmon killed increased with fish density in each stream towards an asymptote. Seven streams in two geographical groups with ≥23 years of data in common were then analyzed for neighborhood density effects. In most (12 of 18) cases predation in a stream was reduced by increasing salmon abundance in neighboring streams. The uncertainty in the estimates for these neighborhood effects may have resulted from interactions between salmon abundance and habitat that influenced foraging by bears, and from bear behavior (e.g., competitive exclusion) and abundance. Taken together, the results indicated that predator-prey interactions depend on density at multiple spatial scales, and on habitat features of the surrounding landscape. Explicit consideration of this context dependency should lead to improved understanding of the ecological impacts of predation across ecosystems and taxa.
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Affiliation(s)
- Thomas P Quinn
- School of Aquatic and Fishery Sciences, University of Washington, Box 355020, Seattle, WA, 98195, USA.
| | - Curry J Cunningham
- School of Aquatic and Fishery Sciences, University of Washington, Box 355020, Seattle, WA, 98195, USA
- School of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Fairbanks, AK, 99775, USA
| | - Aaron J Wirsing
- School of Environmental and Forest Sciences, University of Washington, Box 352100, Seattle, WA, 98195, USA
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Werner JR, Gillis EA, Boonstra R, Krebs CJ. You can hide but you can't run: apparent competition, predator responses and the decline of Arctic ground squirrels in boreal forests of the southwest Yukon. PeerJ 2016; 4:e2303. [PMID: 27635312 PMCID: PMC5012268 DOI: 10.7717/peerj.2303] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Accepted: 07/07/2016] [Indexed: 11/20/2022] Open
Abstract
Throughout much of North America's boreal forest, the cyclical fluctuations of snowshoe hare populations (Lepus americanus) may cause other herbivores to become entrained in similar cycles. Alternating apparent competition via prey switching followed by positive indirect effects are the mechanisms behind this interaction. Our purpose is to document a change in the role of indirect interactions between sympatric populations of hares and arctic ground squirrels (Urocitellus parryii plesius), and to emphasize the influence of predation for controlling ground squirrel numbers. We used mark-recapture to estimate the population densities of both species over a 25-year period that covered two snowshoe hare cycles. We analysed the strength of association between snowshoe hare and ground squirrel numbers, and the changes to the seasonal and annual population growth rates of ground squirrels over time. A hyperbolic curve best describes the per capita rate of increase of ground squirrels relative to their population size, with a single stable equilibrium and a lower critical threshold below which populations drift to extinction. The crossing of this unstable boundary resulted in the subsequent uncoupling of ground squirrel and hare populations following the decline phase of their cycles in 1998. The implications are that this sustained Type II predator response led to the local extinction of ground squirrels. When few individuals are left in a colony, arctic ground squirrels may also have exhibited an Allee effect caused by the disruption of social signalling of approaching predators.
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Affiliation(s)
- Jeffery R Werner
- Biodiversity Research Centre, Department of Zoology, University of British Columbia , Vancouver , British Columbia , Canada
| | - Elizabeth A Gillis
- Department of Resource Management and Protection, Vancouver Island University , Nanaimo , British Columbia , Canada
| | - Rudy Boonstra
- Department of Biological Sciences, University of Toronto, Scarborough , Toronto , Ontario , Canada
| | - Charles J Krebs
- Department of Zoology, University of British Columbia , Vancouver , British Columbia , Canada
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