Where and what to feed? Differential effects on fecundity and longevity in the invasive Drosophila suzukii

Abstract

Successful establishment of invasive species requires that the species meet environmental conditions favouring their longevity and fecundity. When juveniles and adults consume different resources, gravid females may have to choose whether to feed or to reproduce. We used a successful invasive species to test whether female life history traits are affected by the potential nutrients found in reproductive sites. The pest species, Drosophila suzukii, lays eggs in fruits that could provide nutrients since fruit exudates are generated during oviposition. We demonstrated that D. suzukii adults cannot survive when they have only access to reproductive sites (i.e. undamaged fruits). But they can find the nutrients necessary for longevity on these reproductive sites if there are larger holes in the exocarp. Egg maturation is low when D. suzukii feeds on nutrients from fruits, even when damaged, suggesting that females cannot acquire sufficient nutrients for egg maturation where they lay their eggs. Finally, a field experiment supported our laboratory results: wild females have a low degree of egg maturation, even when captured near reproductive sites. Our study hence shows constraints on egg production, and therefore on fruit infestation, determined by the nutritional ecology of pest females.