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Psyche
Volume 2012 (2012), Article ID 495805, 12 pages
http://dx.doi.org/10.1155/2012/495805
Research Article

Plant Feeding in an Omnivorous Mirid, Dicyphus hesperus: Why Plant Context Matters

1Pacific Agri-Food Research Centre, Agriculture and Agri-Food Canada, P.O. Box 1000, Agassiz, BC, Canada V0M 1A0
2Department of Biology, University of Windsor, Windsor, ON, Canada N9B 3P4
3Department of Biology, Douglas College, P.O. Box 2503, New Westminster, BC, Canada V3L 5B2
4Evolutionary and Behavioural Ecology Research Group, Department of Biological Sciences, Simon Fraser University, Burnaby, BC, Canada V5A 1S6

Received 2 August 2012; Accepted 30 August 2012

Academic Editor: Kleber Del-Claro

Copyright © 2012 David R. Gillespie et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

True omnivores that feed on both plant and animal tissues are not additive combinations of herbivore and predator (carnivore). Because true omnivores must distribute adaptive feeding decisions among two disparate tissue types, understanding the context that plants provide for foraging is important to understand their role in food webs. We varied prey and plant resources to investigate the plant context in an omnivorous true bug, Dicyphus hesperus. The contribution of plant species to fitness was unimportant in water acquisition decisions, but affected numbers of prey consumed over longer periods. In plant communities, in the absence of prey, D. hesperus moved to plants with the highest resource quality. Unlike pure predators facing declining prey, omnivores can use a nondepleting resource to fund future foraging without paying a significant cost. However, the dual resource exploitation can also impose significant constraints when both types of resources are essential. The presence of relatively profitable plants that are spatially separate from intermediate consumer populations could provide a mechanism to promote stability within food webs with plant-feeding omnivores. The effects of context in omnivores will require adding second-order terms to the Lotka-Volterra structure to explicitly account for the kinds of interactions we have observed here.