Selection of Molting and Pupation Sites byColeomegilla maculata(Coleoptera: Coccinellidae): Avoidance of Intraguild Predation

Abstract

Molting and pupating insects are especially vulnerable to natural enemies and one possible component of their defensive strategy is the selection of suitable microhabitats. We hypothesized that larvae of the lady beetle Coleomegilla maculata lengi Timberlake select molting and pupation sites that effectively reduce their susceptibility to intraguild predation. We characterized microsites on potato plants and evaluated their associated risk of predation by the lacewing Chrysoperla rufilabris Burmeister (Neuroptera: Chrysopidae), a common intraguild predator. The majority of molts (>60%) occurred on potato plants in sites similar to those used by mobile coccinellid larvae. In contrast, 90% of the larvae left the plant to pupate. Second, third, and fourth instars selected artificial shelters for both molting and pupation when these were available. Vulnerability of pupae and newly molted larvae to lacewing larvae depended on plant microsite, with leaves supporting an aphid colony as the most risky sites. Molting and pupating microhabitat selection by coccinellid larvae appears to be a trade-off between the advantages of remaining close to the aphid resource, and the costs of being exposed to intraguild predators.