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Hijar Islas AC, Milne A, Eizaguirre C, Huang W. Parasite-mediated predation determines infection in a complex predator-prey-parasite system. Proc Biol Sci 2024; 291:20232468. [PMID: 38654648 DOI: 10.1098/rspb.2023.2468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Accepted: 03/15/2024] [Indexed: 04/26/2024] Open
Abstract
The interplay of host-parasite and predator-prey interactions is critical in ecological dynamics because both predators and parasites can regulate communities. But what is the prevalence of infected prey and predators when a parasite is transmitted through trophic interactions considering stochastic demographic changes? Here, we modelled and analysed a complex predator-prey-parasite system, where parasites are transmitted from prey to predators. We varied parasite virulence and infection probabilities to investigate how those evolutionary factors determine species' coexistence and populations' composition. Our results show that parasite species go extinct when the infection probabilities of either host are small and that success in infecting the final host is more critical for the survival of the parasite. While our stochastic simulations are consistent with deterministic predictions, stochasticity plays an important role in the border regions between coexistence and extinction. As expected, the proportion of infected individuals increases with the infection probabilities. Interestingly, the relative abundances of infected and uninfected individuals can have opposite orders in the intermediate and final host populations. This counterintuitive observation shows that the interplay of direct and indirect parasite effects is a common driver of the prevalence of infection in a complex system.
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Affiliation(s)
- Ana C Hijar Islas
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, UK
| | - Amy Milne
- School of Mathematical Sciences, Queen Mary University of London, London, UK
- Department of Mathematics, Swansea University, Swansea, UK
| | - Christophe Eizaguirre
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, UK
| | - Weini Huang
- School of Mathematical Sciences, Queen Mary University of London, London, UK
- Group of Theoretical Biology, School of Life Sciences, Sun Yat-sen University, Guangzhou, People's Republic of China
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2
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Moosmann M, Greenway R, Oester R, Matthews B. The role of fish predators and their foraging traits in shaping zooplankton community structure. Ecol Lett 2024; 27:e14382. [PMID: 38361474 DOI: 10.1111/ele.14382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 01/02/2024] [Accepted: 01/15/2024] [Indexed: 02/17/2024]
Abstract
Differentiation of foraging traits among predator populations may help explain observed variation in the structure of prey communities. However, few studies have investigated the phenotypic effects of predators on their prey in natural communities. Here, we use a comparative analysis of 78 Greenlandic lakes to examine how foraging trait variation among threespine stickleback populations can help explain variation in zooplankton community composition among lakes. We find that landscape-scale variation in zooplankton composition was jointly explained by lake properties, such as size and water chemistry, and the presence and absence of both stickleback and arctic char. Additional variation in zooplankton community structure can be explained by stickleback jaw protrusion, a trait with known utility for foraging on zooplankton, but only in lakes where stickleback co-occur with arctic char. Overall, our results illustrate how trait variation of predators, alongside other ecosystem properties, can influence the composition of prey communities in nature.
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Affiliation(s)
- Marvin Moosmann
- Department of Fish Ecology and Evolution, EAWAG, Kastanienbaum, Switzerland
- Swiss Ornithological Institute, Sempach, Switzerland
| | - Ryan Greenway
- Department of Biology, University of Constance, Constance, Germany
| | - Rebecca Oester
- Department of Aquatic Ecology, EAWAG, Kastanienbaum, Dübendorf, Switzerland
| | - Blake Matthews
- Department of Fish Ecology and Evolution, EAWAG, Kastanienbaum, Switzerland
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3
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Doherty S, Saltré F, Llewelyn J, Strona G, Williams SE, Bradshaw CJA. Estimating co-extinction threats in terrestrial ecosystems. GLOBAL CHANGE BIOLOGY 2023; 29:5122-5138. [PMID: 37386726 DOI: 10.1111/gcb.16836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 05/27/2023] [Indexed: 07/01/2023]
Abstract
The biosphere is changing rapidly due to human endeavour. Because ecological communities underlie networks of interacting species, changes that directly affect some species can have indirect effects on others. Accurate tools to predict these direct and indirect effects are therefore required to guide conservation strategies. However, most extinction-risk studies only consider the direct effects of global change-such as predicting which species will breach their thermal limits under different warming scenarios-with predictions of trophic cascades and co-extinction risks remaining mostly speculative. To predict the potential indirect effects of primary extinctions, data describing community interactions and network modelling can estimate how extinctions cascade through communities. While theoretical studies have demonstrated the usefulness of models in predicting how communities react to threats like climate change, few have applied such methods to real-world communities. This gap partly reflects challenges in constructing trophic network models of real-world food webs, highlighting the need to develop approaches for quantifying co-extinction risk more accurately. We propose a framework for constructing ecological network models representing real-world food webs in terrestrial ecosystems and subjecting these models to co-extinction scenarios triggered by probable future environmental perturbations. Adopting our framework will improve estimates of how environmental perturbations affect whole ecological communities. Identifying species at risk of co-extinction (or those that might trigger co-extinctions) will also guide conservation interventions aiming to reduce the probability of co-extinction cascades and additional species losses.
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Affiliation(s)
- Seamus Doherty
- Global Ecology | Partuyarta Ngadluku Wardli Kuu, College of Science and Engineering, Flinders University, Adelaide, South Australia, Australia
- Australian Research Council Centre of Excellence for Australian Biodiversity and Heritage, Wollongong, New South Wales, Australia
| | - Frédérik Saltré
- Global Ecology | Partuyarta Ngadluku Wardli Kuu, College of Science and Engineering, Flinders University, Adelaide, South Australia, Australia
- Australian Research Council Centre of Excellence for Australian Biodiversity and Heritage, Wollongong, New South Wales, Australia
| | - John Llewelyn
- Global Ecology | Partuyarta Ngadluku Wardli Kuu, College of Science and Engineering, Flinders University, Adelaide, South Australia, Australia
- Australian Research Council Centre of Excellence for Australian Biodiversity and Heritage, Wollongong, New South Wales, Australia
| | - Giovanni Strona
- European Commission, Joint Research Centre, Ispra, Italy
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Stephen E Williams
- Centre for Tropical Environmental and Sustainability Science, College of Science and Engineering, James Cook University, Townsville, Queensland, Australia
| | - Corey J A Bradshaw
- Global Ecology | Partuyarta Ngadluku Wardli Kuu, College of Science and Engineering, Flinders University, Adelaide, South Australia, Australia
- Australian Research Council Centre of Excellence for Australian Biodiversity and Heritage, Wollongong, New South Wales, Australia
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Scott ME. Helminth-host-environment interactions: Looking down from the tip of the iceberg. J Helminthol 2023; 97:e59. [PMID: 37486085 DOI: 10.1017/s0022149x23000433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/25/2023]
Abstract
In 1978, the theory behind helminth parasites having the potential to regulate the abundance of their host populations was formalized based on the understanding that those helminth macroparasites that reduce survival or fecundity of the infected host population would be among the forces limiting unregulated host population growth. Now, 45 years later, a phenomenal breadth of factors that directly or indirectly affect the host-helminth interaction has emerged. Based largely on publications from the past 5 years, this review explores the host-helminth interaction from three lenses: the perspective of the helminth, the host, and the environment. What biotic and abiotic as well as social and intrinsic host factors affect helminths? What are the negative, and positive, implications for host populations and communities? What are the larger-scale implications of the host-helminth dynamic on the environment, and what evidence do we have that human-induced environmental change will modify this dynamic? The overwhelming message is that context is everything. Our understanding of second-, third-, and fourth-level interactions is extremely limited, and we are far from drawing generalizations about the myriad of microbe-helminth-host interactions.Yet the intricate, co-evolved balance and complexity of these interactions may provide a level of resilience in the face of global environmental change. Hopefully, this albeit limited compilation of recent research will spark new interdisciplinary studies, and application of the One Health approach to all helminth systems will generate new and testable conceptual frameworks that encompass our understanding of the host-helminth-environment triad.
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Affiliation(s)
- M E Scott
- Institute of Parasitology, McGill University (Macdonald Campus), 21,111 Lakeshore Road, Ste-Anne de Bellevue, QuebecH9X 3V9, Canada
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Resetarits EJ, Ellis WT, Byers JE. The opposing roles of lethal and nonlethal effects of parasites on host resource consumption. Ecol Evol 2023; 13:e9973. [PMID: 37066062 PMCID: PMC10099202 DOI: 10.1002/ece3.9973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 03/06/2023] [Accepted: 03/12/2023] [Indexed: 04/18/2023] Open
Abstract
Although parasites can kill their hosts, they also commonly cause nonlethal effects on their hosts, such as altered behaviors or feeding rates. Both the lethal and nonlethal effects of parasites can influence host resource consumption. However, few studies have explicitly examined the joint lethal and nonlethal effects of parasites to understand the net impacts of parasitism on host resource consumption. To do this, we adapted equations used in the indirect effects literature to quantify how parasites jointly influence basal resource consumption through nonlethal effects (altered host feeding rate) and lethal effects (increased host mortality). To parametrize these equations and to examine the potential temperature sensitivity of parasite influences, we conducted a fully factorial lab experiment (crossing trematode infection status and a range of temperatures) to quantify feeding rates and survivorship curves of snail hosts. We found that infected snails had significantly higher mortality and ate nearly twice as much as uninfected snails and had significantly higher mortality, resulting in negative lethal effects and positive nonlethal effects of trematodes on host resource consumption. The net effects of parasites on resource consumption were overall positive in this system, but did vary with temperature and experimental duration, highlighting the context dependency of outcomes for the host and ecosystem. Our work demonstrates the importance of jointly investigating lethal and nonlethal effects of parasites and provides a novel framework for doing so.
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Affiliation(s)
- Emlyn J. Resetarits
- Odum School of EcologyUniversity of GeorgiaAthensGeorgia30602USA
- Center for the Ecology of Infectious DiseasesUniversity of GeorgiaAthensGeorgia30602USA
- Marine InstituteUniversity of GeorgiaDarienGeorgia31305USA
| | - William T. Ellis
- Odum School of EcologyUniversity of GeorgiaAthensGeorgia30602USA
| | - James E. Byers
- Odum School of EcologyUniversity of GeorgiaAthensGeorgia30602USA
- Center for the Ecology of Infectious DiseasesUniversity of GeorgiaAthensGeorgia30602USA
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Mallinger EC, Olson ER, Vincent GP, Van Stappen J, Van Deelen T. Factors influencing the presence of parasitic trombiculids on red-backed voles in a temperate archipelago. CAN J ZOOL 2022. [DOI: 10.1139/cjz-2021-0143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Parasites can influence host population health and dynamics and are often an overlooked aspect of the ecology of ecosystems. Understanding the impacts of ecological interactions between parasites and small mammals can provide insights into ecosystem dynamics. We live trapped small mammals within the Apostle Islands archipelago (2017-2020) and assessed factors influencing the presence of mites from the Trombiculidae family. Archipelagos provide unique research opportunities because in small mammal-parasitic trombiculid systems, they are essentially closed systems. We detected trombiculids on 47% of Myodes gapperi (Vigors, 1830; red-backed vole) individuals but rarely detected trombiculids on other species. We developed and ranked a set of a priori logistic regression models of trombiculid presence relative to habitat quality, host abundance, body condition, sex, and sexual maturity to identify factors significant in predicting trombiculid infection for M. gapperi. Parasitic trombiculids were more likely when M. gapperi abundance was high and body condition was poor, however it is unknown whether trombiculids affect condition or if trombiculids are more likely to parasitize hosts in poor condition. The significance of host abundance may indicate density-dependent transmission. Our work suggests that host density and body condition are important factors influencing parasitism by trombiculids in M. gapperi populations.
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Affiliation(s)
| | - Erik R Olson
- Northland College, 1341, Natural Resources, 1411 Ellis Ave, Ashland, Wisconsin, United States, 54806-3999
| | | | - Julie Van Stappen
- Apostle Islands National Lakeshore, Resource Management , Bayfield , Wisconsin, United States
| | - T.R. Van Deelen
- University of Wisconsin, Department of Wildlife Ecology, 217 Russell Labs, Madison, Wisconsin, United States, 53706,
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Context-dependent parasite infection affects trophic niche in populations of sympatric stickleback species. Parasitology 2022; 149:1164-1172. [PMID: 35570701 PMCID: PMC10090597 DOI: 10.1017/s0031182022000531] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
How parasites alter host feeding ecology remains elusive in natural populations. A powerful approach to investigate the link between infection and feeding ecology is quantifying unique and shared responses to parasite infection in related host species within a common environment. Here, 9 pairs of sympatric populations of the three-spined and nine-spined stickleback fishes were sampled across a range of freshwater and brackish habitats to investigate how parasites alter host feeding ecology: (i) biotic and abiotic determinants of parasite community composition, and (ii) to what extent parasite infection correlates with trophic niche specialization of the 2 species, using stable isotope analyses (δ15N and δ13C). It was determined that parasite community composition and host parasite load varied among sites and species and were correlated with dissolved oxygen. It was also observed that the digenean Cyathocotyle sp.'s abundance, a common directly infecting parasite with a complex life cycle, correlated with host δ13C in a fish species-specific manner. In 6 sites, correlations were found between parasite abundance and their hosts' feeding ecology. These effects were location-specific and occasionally host species or host size-specific. Overall, the results suggest a relationship between parasite infection and host trophic niche which may be an important and largely overlooked ecological factor. The population specificity and variation in parasite communities also suggest this effect is multifarious and context-dependent.
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Gagne RB, Crooks KR, Craft ME, Chiu ES, Fountain-Jones NM, Malmberg JL, Carver S, Funk WC, VandeWoude S. Parasites as conservation tools. CONSERVATION BIOLOGY : THE JOURNAL OF THE SOCIETY FOR CONSERVATION BIOLOGY 2022; 36:e13719. [PMID: 33586245 DOI: 10.1111/cobi.13719] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 02/08/2021] [Indexed: 06/12/2023]
Abstract
Parasite success typically depends on a close relationship with one or more hosts; therefore, attributes of parasitic infection have the potential to provide indirect details of host natural history and are biologically relevant to animal conservation. Characterization of parasite infections has been useful in delineating host populations and has served as a proxy for assessment of environmental quality. In other cases, the utility of parasites is just being explored, for example, as indicators of host connectivity. Innovative studies of parasite biology can provide information to manage major conservation threats by using parasite assemblage, prevalence, or genetic data to provide insights into the host. Overexploitation, habitat loss and fragmentation, invasive species, and climate change are major threats to animal conservation, and all of these can be informed by parasites.
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Affiliation(s)
- Roderick B Gagne
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado, USA
| | - Kevin R Crooks
- Department of Fish, Wildlife, and Conservation Biology, Colorado State University, Fort Collins, Colorado, USA
| | - Meggan E Craft
- Department of Veterinary Population Medicine, University of Minnesota, St Paul, Minnesota, USA
| | - Elliott S Chiu
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado, USA
| | | | - Jennifer L Malmberg
- Department of Veterinary Sciences, Wyoming State Veterinary Laboratory, University of Wyoming, Laramie, Wyoming, USA
| | - Scott Carver
- School of Natural Sciences, University of Tasmania, Hobart, Tasmania, Australia
| | - W Chris Funk
- Graduate Degree Program in Ecology, Department of Biology, Colorado State University, Fort Collins, Colorado, USA
| | - Sue VandeWoude
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado, USA
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Kobak J, Rachalewski M, Bącela-Spychalska K. What doesn’t kill you doesn’t make you stronger: Parasites modify interference competition between two invasive amphipods. NEOBIOTA 2021. [DOI: 10.3897/neobiota.69.73734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
We used a freshwater amphipod-microsporidian model (Ponto-Caspian hosts: Dikerogammarus villosus and D. haemobaphes, parasite: Cucumispora dikerogammari) to check whether parasites affect biological invasions by modulating behaviour and intra- and interspecific interactions between the invaders. We tested competition for shelter in conspecific and heterospecific male pairs (one or both individuals infected or non-infected). In general, amphipods of both species increased their shelter occupancy time when accompanied by infected rather than non-infected conspecifics and heterospecifics. Infected amphipods faced lower aggression from non-infected conspecifics. Moreover, D. villosus was more aggressive than D. haemobaphes and more aggressive towards conspecifics vs. heterospecifics. In summary, infection reduced the intra- and interspecific competitivity of amphipods, which became less capable of defending their shelters, despite their unchanged need for shelter occupancy. Dikerogammarus haemobaphes, commonly considered as a weaker competitor, displaced by D. villosus from co-occupied locations, was able to compete efficiently for the shelter with D. villosus when microsporidian infections appeared on the scene. This suggests that parasites may be important mediators of biological invasions, facilitating the existence of large intra- and interspecific assemblages of invasive alien amphipods.
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Hasegawa R, Koizumi I. Relative importance of host‐dependent versus physical environmental characteristics affecting the distribution of an ectoparasitic copepod infecting the mouth cavity of stream salmonid. Ecol Res 2021. [DOI: 10.1111/1440-1703.12262] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ryota Hasegawa
- Graduate School of Environmental Science Hokkaido University Sapporo Japan
| | - Itsuro Koizumi
- Graduate School of Environmental Science Hokkaido University Sapporo Japan
- Faculty of Environmental Earth Science Hokkaido University Sapporo Japan
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EcoQBNs: First Application of Ecological Modeling with Quantum Bayesian Networks. ENTROPY 2021; 23:e23040441. [PMID: 33918806 PMCID: PMC8069849 DOI: 10.3390/e23040441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 03/31/2021] [Accepted: 04/06/2021] [Indexed: 11/26/2022]
Abstract
A recent advancement in modeling was the development of quantum Bayesian networks (QBNs). QBNs generally differ from BNs by substituting traditional Bayes calculus in probability tables with the quantum amplification wave functions. QBNs can solve a variety of problems which are unsolvable by, or are too complex for, traditional BNs. These include problems with feedback loops and temporal expansions; problems with non-commutative dependencies in which the order of the specification of priors affects the posterior outcomes; problems with intransitive dependencies constituting the circular dominance of the outcomes; problems in which the input variables can affect each other, even if they are not causally linked (entanglement); problems in which there may be >1 dominant probability outcome dependent on small variations in inputs (superpositioning); and problems in which the outcomes are nonintuitive and defy traditional probability calculus (Parrondo’s paradox and the violation of the Sure Thing Principle). I present simple examples of these situations illustrating problems in prediction and diagnosis, and I demonstrate how BN solutions are infeasible, or at best require overly-complex latent variable structures. I then argue that many problems in ecology and evolution can be better depicted with ecological QBN (EcoQBN) modeling. The situations that fit these kinds of problems include noncommutative and intransitive ecosystems responding to suites of disturbance regimes with no specific or single climax condition, or that respond differently depending on the specific sequence of the disturbances (priors). Case examples are presented on the evaluation of habitat conditions for a bat species, representing state-transition models of a boreal forest under disturbance, and the entrainment of auditory signals among organisms. I argue that many current ecological analysis structures—such as state-and-transition models, predator–prey dynamics, the evolution of symbiotic relationships, ecological disturbance models, and much more—could greatly benefit from a QBN approach. I conclude by presenting EcoQBNs as a nascent field needing the further development of the quantum mathematical structures and, eventually, adjuncts to existing BN modeling shells or entirely new software programs to facilitate model development and application.
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