Ovipositional preference, fidelity, and fitness of Drosophila suzukii in a co-occurring crop and non-crop host system

Abstract

Drosophila suzukii (Matsumura) is a devastating pest of soft-skinned fruits including blackberries and raspberries. Management of this pest is focused on preventing infestation in crops, but non-crop hosts may play an important role in enabling D. suzukiito persist in the absence of cultivated hosts. Drosophila suzukii may also infest fruits of both crop and non-crop hosts concurrently. Our goals were to determine whether (1) D. suzukiiprefers to oviposit in cultivated blackberry, Rubus L. subgenus rubus Watson, or American pokeweed, Phytolacca americana, a non-crop host commonly found along field edges, (2) D. suzukii prefers to oviposit into the same host from which it emerged, and (3) performance differs between D. suzukii progeny that develop in blackberries or pokeweed berries. Although the pest was able to infest both hosts at the same rate, we found that D. suzukii females emerging from pokeweed preferred to oviposit into blackberries, while females emerging from blackberry had no preference. Progeny that developed in blackberries were more fit than progeny that developed in pokeweed berries based on several measures. In field locations, cultivated blackberries and pokeweed berries only overlapped in availability for a short period of time, and infestation rates were variable between blackberries and pokeweed berries collected during that period. Nonetheless, these results suggest that non-crop hosts may facilitate the invasion of D. suzukii and perpetuate infestation of cultivated hosts under certain circumstances.