Developmental stage-specific chemotaxis in the invasive spotted-wing drosophila: Detection of potential competitors and habitat selection

The spotted-wing drosophila (Drosophila suzukii) is an invasive pest native to Southeast Asia that has rapidly spread worldwide, primarily infesting berries and stone fruits. Unlike other drosophilids, which typically oviposit in decaying organic matter, D. suzukii preferentially targets ripening fruits. This behavioral shift reduces interspecific competition at oviposition sites. Previous studies have demonstrated that adult D. suzukii can detect pheromonal cues emitted by Drosophila melanogaster, a potential competitor. However, whether this chemosensory capacity is conserved across developmental stages or specific to certain Drosophila species remains unclear. In the present study, we demonstrate that D. suzukii larvae are capable of distinguishing between substrates previously occupied by conspecific versus heterospecific larvae. Ongoing experiments aim to determine whether this discrimination is driven by compounds produced by larvae, adults, or both. Concurrently, adult responses to these same chemical cues are being evaluated. Additional work is also in progress to assess larval responses to specific D. melanogaster pheromones, providing further insight into the extent of chemosensory congruence between life stages. These findings suggest that D. suzukii possesses a distinctive chemosensory repertoire enabling the detection of potential competitors. This sensory capability likely contributes to its ecological success and invasiveness by facilitating avoidance of suboptimal habitats for reproduction.