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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http://dx.doi.org/10.1002/ps.6825 | DOI Listing |
The Arctic has warmed nearly four times faster than the global average since 1979, resulting in rapid glacier retreat and exposing new glacier forelands. These forelands offer unique experimental settings to explore how global warming impacts ecosystems, particularly for highly climate-sensitive arthropods. Understanding these impacts can help anticipate future biodiversity and ecosystem changes under ongoing warming scenarios.
View Article and Find Full Text PDFEcology
December 2024
U.S. Geological Survey, New York Cooperative Fish and Wildlife Research Unit, Department of Natural Resources and the Environment, Cornell University, Ithaca, New York, USA.
Interspecific competition can significantly impact marine ecosystems by affecting species distributions and abundances. Understanding how sympatric species utilize available food helps identify potential competition and its effects when resources are limited. Here, we applied a suite of analytical methods (diet analysis, stable isotopes, and biomass estimates) to identify potential competitive interactions among North Pacific pelagic predators.
View Article and Find Full Text PDFJ Mammal
December 2024
USDA National Wildlife Research Center, 4101 Laporte Avenue, Fort Collins, CO 80521, United States.
The consequences of intraguild predation on vulnerable subordinate species are an important consideration in the recovery of endangered species. In prairie ecosystems, coyotes () are the primary predator of endangered black-footed ferrets (; hereafter, ferrets) and presumably compete for prairie dog ( spp.) prey.
View Article and Find Full Text PDFJ Math Biol
November 2024
Department of Mathematics, University of Louisiana at Lafayette, Lafayette, LA, 70503, USA.
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