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Snyder GB, Smith OM, Chapman EG, Crossley MS, Crowder DW, Fu Z, Harwood JD, Jensen AS, Krey KL, Lynch CA, Snyder WE. Alternative prey mediate intraguild predation in the open field. PEST MANAGEMENT SCIENCE 2022; 78:3939-3946. [PMID: 35124892 DOI: 10.1002/ps.6825] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2021] [Revised: 01/27/2022] [Accepted: 02/06/2022] [Indexed: 06/14/2023]
Abstract
BACKGROUND Generalist predators that kill and eat other natural enemies can weaken biological control. However, pest suppression can be disrupted even if actual intraguild predation is infrequent, if predators reduce their foraging to lower their risk of being killed. In turn, predator-predator interference might be frequent when few other prey are available, but less common when herbivorous and detritus-feeding prey are plentiful. We used molecular gut-content analysis to track consumption of the predatory bug Geocoris sp. by the larger intraguild predator Nabis sp., in organic and conventional potato (Solanum tuberosum) fields. RESULTS We found that higher densities of both aphids and thrips, two common herbivores, correlated with higher probability of detecting intraguild predation. Perhaps, Nabis foraging for these herbivores also encountered and ate more Geocoris. Surprisingly, likelihood of intraguild predation was not strongly linked to densities of either Nabis or Geocoris, or farming system, suggesting a greater importance for prey than predator community structure. Intriguingly, we found evidence that Geocoris fed more often on the detritus-feeding fly Scaptomyza pallida with increasing predator evenness. This would be consistent with Geocoris shifting to greater foraging on the ground, where S. pallida would be relatively abundant, in the face of greater risk of intraguild predation. CONCLUSION Overall, our findings suggest that while herbivorous prey may heighten intraguild predation of Geocoris in the foliage, detritivores might support a shift to safer foraging on the ground. This provides further evidence that prey abundance and diversity can act to either heighten or relax predator-predator interference, depending on prey species identity and predator behavior. © 2022 Society of Chemical Industry.
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Affiliation(s)
- Gretchen B Snyder
- Department of Entomology, Washington State University, Pullman, WA, USA
| | - Olivia M Smith
- Department of Entomology, University of Georgia, Athens, GA, USA
| | - Eric G Chapman
- Department of Entomology, University of Kentucky, Lexington, KY, USA
| | - Michael S Crossley
- Department of Entomology and Wildlife Ecology, University of Delaware, Newark, DE, USA
| | - David W Crowder
- Department of Entomology, Washington State University, Pullman, WA, USA
| | - Zhen Fu
- Department of Entomology, Washington State University, Pullman, WA, USA
| | - James D Harwood
- Institute of Plant and Environment Protection, Beijing Academy of Agricultural and Forestry Sciences, Beijing, China
| | | | - Karol L Krey
- Department of Entomology, Washington State University, Pullman, WA, USA
| | - Christine A Lynch
- Department of Entomology, Washington State University, Pullman, WA, USA
| | - William E Snyder
- Department of Entomology, University of Georgia, Athens, GA, USA
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Lynch CA, Smith OM, Chapman EG, Crossley MS, Crowder DW, Fu Z, Harwood JD, Jensen AS, Krey KL, Snyder GB, Snyder WE. Alternative prey and farming system mediate predation of Colorado potato beetles by generalists. PEST MANAGEMENT SCIENCE 2022; 78:3769-3777. [PMID: 34250727 DOI: 10.1002/ps.6553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 07/11/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND Biological control by generalist predators can be mediated by the abundance and biodiversity of alternative prey. When alternative prey draw predator attacks away from the control target, they can weaken pest suppression. In other cases, a diverse prey base can promote predator abundance and biodiversity, reduce predator-predator interference, and benefit biocontrol. Here, we used molecular gut-content analysis to assess how community composition altered predation of Colorado potato beetle (Leptinotarsa decemlineata (Say)) by Nabis sp. and Geocoris sp. Predators were collected from organic or conventional potato (Solanum tuberosum L.) fields, encouraging differences in arthropod community composition. RESULTS In organic fields, Nabis predation of potato beetles decreased with increasing arthropod richness and predator abundance. This is consistent with Nabis predators switching to other prey species when available and with growing predator-predator interference. In conventional fields these patterns were reversed, however, with potato beetle predation by Nabis increasing with greater arthropod richness and predator abundance. For Geocoris, Colorado potato beetle predation was more frequent in organic than in conventional fields. However, Geocoris predation of beetles was less frequent in fields with higher abundance of the detritus-feeding fly Scaptomyza pallida Zetterstedt, or of all arthropods, consistent with predators choosing other prey when available. CONCLUSION Alternative prey generally dampened predation of potato beetles, suggesting these pests were less-preferred prey. Nabis and Geocoris differed in which alternative prey were most disruptive to feeding on potato beetles, and in the effects of farm management on predation, consistent with the two predator species occupying complementary feeding niches. © 2021 Society of Chemical Industry.
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Affiliation(s)
- Christine A Lynch
- Department of Entomology, Washington State University, Pullman, WA, USA
| | - Olivia M Smith
- Department of Entomology, University of Georgia, Athens, GA, USA
| | - Eric G Chapman
- Department of Entomology, University of Kentucky, Lexington, KY, USA
| | | | - David W Crowder
- Department of Entomology, Washington State University, Pullman, WA, USA
| | - Zhen Fu
- Department of Entomology, Washington State University, Pullman, WA, USA
| | - James D Harwood
- Institute of Plant and Environment Protection, Beijing Academy of Agricultural and Forestry Sciences, Beijing, China
| | | | - Karol L Krey
- Department of Entomology, Washington State University, Pullman, WA, USA
| | - Gretchen B Snyder
- Department of Entomology, Washington State University, Pullman, WA, USA
| | - William E Snyder
- Department of Entomology, University of Georgia, Athens, GA, USA
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Smith OM, Chapman EG, Crossley MS, Crowder DW, Fu Z, Harwood JD, Jensen AS, Krey KL, Lynch CA, Snyder GB, Snyder WE. Alternative Prey and Predator Interference Mediate Thrips Consumption by Generalists. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.752159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Generalist predators’ complex feeding relationships make it difficult to predict their contribution to pest suppression. Alternative prey can either distract predators from attacking pests, weakening biocontrol, or provide food that support larger predator communities to enhance it. Similarly, predator species might both feed upon and complement one another by occupying different niches. Here, we use molecular gut-content analysis to examine predation of western flower thrips (Frankliniella occidentalis) by two generalist predatory bugs, Geocoris sp. and Nabis sp. We collected predators from conventional and organic potato fields that differed in arthropod abundance and composition, so that we could draw correlations between abundance and biodiversity of predators and prey, and thrips predation. We found that alternative prey influenced the probability of detecting Geocoris predation of thrips through a complex interaction. In conventionally-managed potato fields, thrips DNA was more likely to be detected in Geocoris as total abundance of all arthropods in the community increased. But the opposite pattern was found in organic fields, where the probability of detecting thrips predation by Geocoris decreased with increasing total arthropod abundance. Perhaps, increasing abundance (from a relatively low baseline) of alternative prey triggered greater foraging activity in conventional fields, but drew attacks away from thrips in organic fields where prey were consistently relatively bountiful. The probability of detecting Geocoris predation of thrips generally increased with increasing thrips density, but this correlation was steeper in organic than conventional fields. For both Geocoris and Nabis, greater Nabis abundance correlated with reduced probability of detecting thrips DNA; for Nabis this was the only important variable. Nabis is a common intraguild predator of the smaller Geocoris, and is highly cannibalistic, suggesting that predator-predator interference increased with more Nabis present. Complex patterns of thrips predation seemed to result from a dynamic interaction with alternative prey abundance, alongside consistently negative interactions among predators. This provides further evidence that alternative prey and predator interference must be studied in concert to accurately predict the contributions of generalists to biocontrol.
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Rinehart S, Long JD. Numerical responses of omnivorous arthropods to plant alternative resources suppress prey populations: a meta-analysis. Ecology 2021; 103:e3623. [PMID: 34967951 DOI: 10.1002/ecy.3623] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 09/13/2021] [Accepted: 10/13/2021] [Indexed: 11/11/2022]
Abstract
Omnivory is ubiquitous in ecological communities. Yet, we lack a consensus of how plant alternative resources impact the ability of omnivores to suppress prey populations. Previous work suggests that plant alternative resources can increase, decrease, or have no effect on the magnitude of omnivore-prey interactions. This discrepancy may arise from 1) the ability of omnivores to numerically respond to plant alternative resources and 2) identity-specific effects of plant alternative resources. We used a meta-analysis to examine how omnivore numerical responses and the identity of plant alternative resources affect 1) omnivore predation rates (mainly reported as per capita predation rate) and 2) omnivore impacts on prey population density. Plant alternative resources reduced omnivore predation rate regardless of identity. The suppression of predation rate by flowers and flowering plants was magnified when pollen alone was tested as the alternative resource. Surprisingly, plant alternative resource availability reduced prey density, suggesting that omnivore predation increased with plant alternative resources. This discrepancy (plant alternative resources decreased omnivore predation rates but also decreased prey density) resulted from experimental differences in the ability of omnivores to respond numerically to plant alternative resources. In the presence of plant alternative resources, allowing omnivore numerical responses decreased prey density, while not allowing numerical responses increased prey density. Because omnivores commonly suppress prey density in the presence of plant alternative resources when numerical responses of omnivores are allowed, the effectiveness of biological control may depend upon the availability of such resources and the facilitation of numerical responses. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- S Rinehart
- Department of Biological Sciences, University of Alabama, Tuscaloosa, AL.,Department of Biology and the Coastal and Marine Institute Laboratory, San Diego State University, San Diego, CA.,Department of Evolution and Ecology, University of California Davis, Davis, CA
| | - J D Long
- Department of Biology and the Coastal and Marine Institute Laboratory, San Diego State University, San Diego, CA
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van der Lee GH, Vonk JA, Verdonschot RCM, Kraak MHS, Verdonschot PFM, Huisman J. Eutrophication induces shifts in the trophic position of invertebrates in aquatic food webs. Ecology 2020; 102:e03275. [PMID: 33351184 PMCID: PMC7988625 DOI: 10.1002/ecy.3275] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 09/11/2020] [Accepted: 10/26/2020] [Indexed: 11/13/2022]
Abstract
Changes in the ecological stoichiometry of primary producers may have considerable implications for energy and matter transfer in food webs. We hypothesized that nutrient enrichment shifts the trophic position of omnivores towards herbivory, as the nutritional quality of primary producers increases. This hypothesis was tested by analyzing the ecological stoichiometry and stable isotope signature of primary producers and a wide range of aquatic macroinvertebrates, including primary consumers (herbivores) and secondary consumers (both potential omnivores and strict carnivores), along a eutrophication gradient in an agricultural landscape. Our results showed (1) that carbon : nutrient ratios of primary producers decreased along the eutrophication gradient, while the elemental composition of consumers remained homeostatic, and (2) that the trophic position of several omnivores and the generalist predator Notonecta decreased, while the trophic position of most other consumers remained constant. These findings suggest that shifts in the diets of aquatic invertebrates induced by increasing eutrophication may affect species interactions and food web structure in aquatic ecosystems.
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Affiliation(s)
- Gea H van der Lee
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94240, Amsterdam, 1090 GE, The Netherlands.,Wageningen Environmental Research, Wageningen UR, P.O. Box 47, Wageningen, 6700 AA, The Netherlands
| | - J Arie Vonk
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94240, Amsterdam, 1090 GE, The Netherlands
| | - Ralf C M Verdonschot
- Wageningen Environmental Research, Wageningen UR, P.O. Box 47, Wageningen, 6700 AA, The Netherlands
| | - Michiel H S Kraak
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94240, Amsterdam, 1090 GE, The Netherlands
| | - Piet F M Verdonschot
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94240, Amsterdam, 1090 GE, The Netherlands.,Wageningen Environmental Research, Wageningen UR, P.O. Box 47, Wageningen, 6700 AA, The Netherlands
| | - Jef Huisman
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94240, Amsterdam, 1090 GE, The Netherlands
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Mkenda PA, Ndakidemi PA, Mbega E, Stevenson PC, Arnold SEJ, Gurr GM, Belmain SR. Multiple ecosystem services from field margin vegetation for ecological sustainability in agriculture: scientific evidence and knowledge gaps. PeerJ 2019; 7:e8091. [PMID: 31799074 PMCID: PMC6885351 DOI: 10.7717/peerj.8091] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 10/23/2019] [Indexed: 01/12/2023] Open
Abstract
Background Field margin and non-crop vegetation in agricultural systems are potential ecosystem services providers because they offer semi-natural habitats for both below and above ground animal groups such as soil organisms, small mammals, birds and arthropods that are service supplying units. They are considered as a target area for enhancing farm biodiversity. Methodology To explore the multiple potential benefits of these semi-natural habitats and to identify research trends and knowledge gaps globally, a review was carried out following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A total of 235 publications from the year 2000 to 2016 in the Scopus and Web of Science databases were reviewed. Results The literature showed an increasing trend in the number of published articles over time with European studies leading in the proportion of studies conducted, followed by North America, Asia, South America, Africa and Australia. Several functional groups of organisms were studied from field margin and non-crop vegetation around agricultural lands including natural enemies (37%), insect pests (22%), birds (17%), pollinators (16%), soil macro fauna (4%) and small mammals (4%). Ecosystem services derived from the field margin included natural pest regulation, pollination, nutrient cycling and reduced offsite erosion. Some field margin plants were reported to host detrimental crop pests, a major ecosystem dis-service, potentially leading to increased pest infestation in the field. Conclusion The majority of studies revealed the importance of field margin and non-crop vegetation around arable fields in enhancing ecosystem biodiversity. Promotion of field margin plants that selectively enhance the population of beneficial organisms would support sustainable food security rather than simply boosting plant diversity. Our analyses also highlight that agro-ecological studies remain largely overlooked in some regions.
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Affiliation(s)
- Prisila A Mkenda
- Department of Sustainable Agriculture, Biodiversity and Ecosystems Management, Nelson Mandela African Institution of Science and Technology, Arusha, Tanzania.,School of Agricultural and Wine Sciences, Charles Sturt University, Wagga Wagga, NSW, Australia.,Department of Biosciences, Sokoine University of Agriculture, Morogoro, Tanzania
| | - Patrick A Ndakidemi
- Department of Sustainable Agriculture, Biodiversity and Ecosystems Management, Nelson Mandela African Institution of Science and Technology, Arusha, Tanzania
| | - Ernest Mbega
- Department of Sustainable Agriculture, Biodiversity and Ecosystems Management, Nelson Mandela African Institution of Science and Technology, Arusha, Tanzania
| | - Philip C Stevenson
- Natural Resources Institute, University of Greenwich, Chatham Maritime, Kent, UK.,Royal Botanic Gardens, Kew, Richmond, Surrey, UK
| | - Sarah E J Arnold
- Natural Resources Institute, University of Greenwich, Chatham Maritime, Kent, UK
| | - Geoff M Gurr
- School of Agricultural and Wine Sciences, Charles Sturt University, Wagga Wagga, NSW, Australia.,Institute of Applied Ecology, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Steven R Belmain
- Natural Resources Institute, University of Greenwich, Chatham Maritime, Kent, UK
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Puentes A, Stephan JG, Björkman C. A Systematic Review on the Effects of Plant-Feeding by Omnivorous Arthropods: Time to Catch-Up With the Mirid-Tomato Bias? Front Ecol Evol 2018. [DOI: 10.3389/fevo.2018.00218] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Dumont F, Aubry O, Lucas E. From Evolutionary Aspects of Zoophytophagy to Biological Control. Front Ecol Evol 2018. [DOI: 10.3389/fevo.2018.00221] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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9
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Vidal MC, Murphy SM. Bottom‐up vs. top‐down effects on terrestrial insect herbivores: a meta‐analysis. Ecol Lett 2017; 21:138-150. [DOI: 10.1111/ele.12874] [Citation(s) in RCA: 126] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 04/03/2017] [Accepted: 10/04/2017] [Indexed: 02/06/2023]
Affiliation(s)
- Mayra C. Vidal
- Department of Biological Sciences University of Denver Denver CO USA
| | - Shannon M. Murphy
- Department of Biological Sciences University of Denver Denver CO USA
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Liman A, Eklund K, Björkman C. Predator refuges for conservation biological control in an intermediately disturbed system: the rise and fall of a simple solution. J Appl Ecol 2016. [DOI: 10.1111/1365-2664.12709] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Anna‐Sara Liman
- Department of Ecology Swedish University of Agricultural Sciences P.O Box 7044 SE‐75007 Uppsala Sweden
| | - Karin Eklund
- Department of Ecology Swedish University of Agricultural Sciences P.O Box 7044 SE‐75007 Uppsala Sweden
| | - Christer Björkman
- Department of Ecology Swedish University of Agricultural Sciences P.O Box 7044 SE‐75007 Uppsala Sweden
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Han P, Dong Y, Lavoir AV, Adamowicz S, Bearez P, Wajnberg E, Desneux N. Effect of plant nitrogen and water status on the foraging behavior and fitness of an omnivorous arthropod. Ecol Evol 2015; 5:5468-77. [PMID: 27069598 PMCID: PMC4813102 DOI: 10.1002/ece3.1788] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Revised: 09/05/2015] [Accepted: 09/17/2015] [Indexed: 11/26/2022] Open
Abstract
Omnivorous arthropods make dietary choices according to the environment in which they forage, mainly availability/quality of plant and/or prey resources. Such decisions and their subsequent impacts on life‐history traits may be affected by the availability of nutrients and water to plants, that is, through bottom‐up forces. By setting up arenas for feeding behavior observation as well as glasshouse cages for plant preference assessment, we studied effects of the presence of prey (Lepidoptera eggs) and nitrogen/water availability to host tomato plants on the foraging behavior and life‐history traits in the omnivorous predator Macrolophus pygmaeus (Heteroptera: Miridae). In the absence of prey, the predator fed equally on the plants treated with various levels of nitrogen and water. In the presence of prey, however, the feeding rate on plants decreased when the plant received low water input. The feeding rate on prey was positively correlated with feeding rate on plants; that is, prey feeding increased with plant feeding when the plants received high water input. Moreover, plants receiving high water input attracted more M. pygmaeus adults compared with those receiving low water input. For M. pygmaeus fitness, the presence of prey enhanced its fertility and longevity, but the longevity decreased when plants received low compared with high water input. In conclusion, the omnivorous predator may be obliged to feed on plants to obtain water, and plant water status may be a limiting factor for the foraging behavior and fitness of the omnivorous predator.
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Affiliation(s)
- Peng Han
- INRA (French National Institute for Agricultural Research) Univ. Nice Sophia Antipolis CNRS UMR 1355-7254 Institut Sophia Agrobiotech 06903 Sophia Antipolis France
| | - Yongcheng Dong
- INRA (French National Institute for Agricultural Research) Univ. Nice Sophia Antipolis CNRS UMR 1355-7254 Institut Sophia Agrobiotech 06903 Sophia Antipolis France; Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory College of Plant Science and Technology Huazhong Agricultural University Wuhan 430070 China
| | - Anne-Violette Lavoir
- INRA (French National Institute for Agricultural Research) Univ. Nice Sophia Antipolis CNRS UMR 1355-7254 Institut Sophia Agrobiotech 06903 Sophia Antipolis France
| | | | - Philippe Bearez
- INRA (French National Institute for Agricultural Research) Univ. Nice Sophia Antipolis CNRS UMR 1355-7254 Institut Sophia Agrobiotech 06903 Sophia Antipolis France
| | - Eric Wajnberg
- INRA (French National Institute for Agricultural Research) Univ. Nice Sophia Antipolis CNRS UMR 1355-7254 Institut Sophia Agrobiotech 06903 Sophia Antipolis France
| | - Nicolas Desneux
- INRA (French National Institute for Agricultural Research) Univ. Nice Sophia Antipolis CNRS UMR 1355-7254 Institut Sophia Agrobiotech 06903 Sophia Antipolis France
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van Baalen M, Krivan V, van Rijn PC, Sabelis MW. Alternative food, switching predators, and the persistence of predator-prey systems. Am Nat 2008; 157:512-24. [PMID: 18707259 DOI: 10.1086/319933] [Citation(s) in RCA: 264] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Sigmoid functional responses may arise from a variety of mechanisms, one of which is switching to alternative food sources. It has long been known that sigmoid (Holling's Type III) functional responses may stabilize an otherwise unstable equilibrium of prey and predators in Lotka-Volterra models. This poses the question of under what conditions such switching-mediated stability is likely to occur. A more complete understanding of the effect of predator switching would therefore require the analysis of one-predator/two-prey models, but these are difficult to analyze. We studied a model based on the simplifying assumption that the alternative food source has a fixed density. A well-known result from optimal foraging theory is that when prey density drops below a threshold density, optimally foraging predators will switch to alternative food, either by including the alternative food in their diet (in a fine-grained environment) or by moving to the alternative food source (in a coarse-grained environment). Analyzing the population dynamical consequences of such stepwise switches, we found that equilibria will not be stable at all. For suboptimal predators, a more gradual change will occur, resulting in stable equilibria for a limited range of alternative food types. This range is notably narrow in a fine-grained environment. Yet, even if switching to alternative food does not stabilize the equilibrium, it may prevent unbounded oscillations and thus promote persistence. These dynamics can well be understood from the occurrence of an abrupt (or at least steep) change in the prey isocline. Whereas local stability is favored only by specific types of alternative food, persistence of prey and predators is promoted by a much wider range of food types.
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Affiliation(s)
- M van Baalen
- Institute of Biodiversity and Ecosystem Dynamics, Population Biology Section, University of Amsterdam, Kruislaan 320, 1098 SM Amsterdam, The Netherlands.
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Abstract
Trait-mediated interactions (TMII) can alter the outcome or magnitude of species interactions. We examined how the interaction between a guild of ground and rove beetles and their fly egg prey was altered by a larger predator, the ground beetle Pterostichus melanarius, and an additional prey, aphids. In field and laboratory experiments, we manipulated the presence or absence of P. melanarius and aphids and recorded the impact of these manipulations on beetle activity and fly egg predation. Individually, aphids, by serving as preferred prey, and P. melanarius, by reducing focal beetle activity, weakened egg predation. However, egg predation was restored when both aphids and P. melanarius were present together, because aphids triggered greater foraging activity, and thus increased incidental predation of fly eggs, by P. melanarius. Thus, TMII among subsets of the community that were disruptive to predation on fly eggs could not be summed to predict the dominant, positive TMII within a more diverse community. Future TMII studies should include more realistic representations of species diversity, and should not ignore the influence of prey on predator behavior.
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Affiliation(s)
- Renée P Prasad
- Department of Entomology, Washington State University, Pullman 99164, USA
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Matsumura M, Trafelet-Smith GM, Gratton C, Finke DL, Fagan WF, Denno RF. DOES INTRAGUILD PREDATION ENHANCE PREDATOR PERFORMANCE? A STOICHIOMETRIC PERSPECTIVE. Ecology 2004. [DOI: 10.1890/03-0629] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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