Chronic, predator-induced stress alters development and reproductive performance of the cotton bollworm, Helicoverpa armigera

Predators can significantly impact potential prey without consuming them, generating potential ramifications for biological control. In this study, we examined the cumulative impacts of adult Harmonia axyridis Pallas (Coleoptera: Coccinellidae) on development and reproduction of Helicoverpa armigera Hubner (Lepidoptera: Noctuidae), over three generations. Development became faster in each of the three generations and pupae became heavier than controls, although survival declined in the third generation. Predator stress increased wing deformations in the first generation, but not thereafter, and female fecundity became higher than controls in the third generation. We concluded that predator stress increased larval consumption to eventually result in both faster development and larger adult size when food was abundant. The results demonstrated that H. armigera could respond to exposure from a non-consumptive predator by shifting aspects of developmental timing and increasing reproductive effort, with both individual- and population-level consequences. The adaptive significances of these changes are discussed. This study advances our understanding of the potential for non-lethal predators to impact prey life histories.