Submitted to: Animal Behaviour
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/14/2007
Publication Date: 3/4/2008
Citation: Lundgren, J.G., Fergen, J.K., Riedell, W.E. 2008. The Influence of Plant Anatomy on Oviposition and Reproductive Success of the Omnivorous Bug, Orius Insidiosus. Animal Behaviour. 75:1495-1502. Interpretive Summary: This research shows how predatory insects respond to plant characteristics, and gives insight how plant diversity in cropland can promote natural enemies of soybean insect pests. Specifically, we found that reproductive behavior in Orius insidiosus, a major predator of soybean aphids, was influenced by the anatomical features (epidermis thickness and trichome density) of plants on which this species lays its eggs. The same plant characteristics that influenced the reproductive decision of the female were associated with the improved survival of her offspring, such that females were laying eggs on plants that were best for her progeny. This research gives support for how maintaining low levels of weeds or cover crops in soybeans may allow for O. insidiosus to reduce the need for insecticides as a management tool for soybean aphid.
Technical Abstract: The mechanisms whereby plant characteristics influence the reproductive behavior and immature survival of omnivorous insects are poorly understood. We examined how trichome density and internal anatomy of five plant species influence the oviposition behavior of zoophytophagous Orius insidiosus and the subsequent longevity of its progeny on the different plants. Female O. insidiosus oviposit into plant species with the thinnest layers of epidermal and collenchyma cells, a decision that is significantly correlated with the survival of their offspring. Once a plant species is chosen, the female mainly bases her oviposition decisions on epidermal thickness and trichome densities. That longevity of nymphs in the absence of prey is positively correlated both with the plant preferences displayed by ovipositing females and the thicknesses of the external coverings of the plants suggest that facultative phytophagy is of great importance to the life history of the immatures. Microscopic examination of plant anatomical features revealed that vascular and cellular tissues are fully accessible to the piercing-sucking mouthparts of the developing insects, and suggest multiple sources of plant nutrients to this omnivore. The ecological and agronomic implications of plant-based mechanisms for O. insidiosus fitness are discussed.