Impact of short- and long-term heat stress on reproductive potential of Drosophila suzukii Matsumura (Diptera: Drosophilidae)

Drosophila suzukii Matsumura (Diptera: Drosophilidae) is an invasive vinegar fly of Asian origin now distributed throughout North America. Due to the unique morphology of females, this fly has become one of the most serious pests of thin-skinned fruits including blueberry, blackberry, cherry, raspberry, and strawberry. Prophylactic insecticide applications are commonly used to control this fly. A more sustainable approach to managing this invasive pest may not be possible without a clear understanding of the biology of this species under extreme environmental conditions. Specifically, high temperature is known to interfere with development and reproduction of drosophilids; however, the impact of high temperature on D. suzukii needs to be further investigated. The objective of the present study was to investigate the impact of exposure to constant and relatively short-term heat stress on reproductive success of D. suzukii, and potential for recovery. Results show that the development and reproduction of D. suzukii were negatively affected by constant and relatively short-term heat stress. Under constant heat stress, oviposition rate and adult lifespan decreased as temperature increased from 24 °C to 33 °C and reproduction was completely absent at 33 °C. Under relatively short-term heat stress, oviposition, pupation, and adult eclosion were significantly decreased as temperature increased from 28 °C to 34 °C. The short-term heat stress greatly reduced the fertility of both male and female D. suzukii which was recovered eight days after treatment. This study provides basic information on thermal biology of D. suzukii to help us better understand the trends commonly observed in D. suzukii trap captures in regions with hot summer conditions, and the results can be used in population models to predict its population dynamics in regions where high temperatures prevail during the field season.