Azadirachtin-Induced Hormesis Mediating Shift in Fecundity-Longevity Trade-Off in the Mexican Bean Weevil (Chrysomelidae: Bruchinae)

ABSTRACT Insecticides can have lethal or sublethal effects upon targeted pest species, and sublethal effects may even favor pest outbreaks if insecticide-induced hormesis occurs. Hormesis is a biphasic dose—response of a given chemical compound that is stimulatory at low doses and toxic at high doses. The former response may result from the disruption of animal homeostasis leading to trade-off shifts between basic ecophysiological processes. A growing interest in the use of biorational insecticides, such as azadirachtin to control stored-product pests, raises concerns about potential sublethal effects. In this study, we explored the hypothesis that azadirachtin can negatively impact the reproductive capacity of the Mexican bean weevil, Zabrotes subfasciatus (Boheman) (Chrysomelidae: Bruchinae), a key pest of stored beans. In addition,weinvestigated whether adults of this species could compensate for any sublethal effect that might have affected any of their reproductive parameters by adjusting the allocat...