Limited behavioral flexibility in oviposition behavior for the invasive fly Zaprionus indianus

Abstract

Zaprionus indianus Gupta (Diptera: Drosophilidae) is a fly species native to the Afrotropical biogeographic region that expanded its geographical distribution to the American continent around 1999. This fly lays eggs, feeds, and develops on a wide variety of fruits colonized by yeasts and bacteria, as well as on ripe, non-damaged soft-skinned fruits. The arrival of Z. indianus to American ecosystems entails co-existence with other drosophilid species with the same resource specificity, such as the cosmopolitan human commensal Drosophila melanogaster Meigen. In this scenario, the oviposition strategy could be relevant for invasion success in terms of partitioning the utilization of resources in space or time. We investigated whether Z. indianus avoids laying eggs in resources previously used by another species (D. melanogaster), or whether oviposition is unaffected by the presence of other species’ larvae. Results show a stable oviposition behavior of Z. indianus, considering that this fly lays the same number of eggs regardless of whether the oviposition resource has larvae of other species, whereas D. melanogaster showed a flexible oviposition behavior when presented with the same oviposition resources. Zaprionus indianus being a good larval competitor against other drosophilids, this stable oviposition strategy could be positive for invasiveness as it ensures a continuous spread of eggs and subsequent larval development during invasion in new and heterogeneous ecosystems.