Larval Movement of Spotted Wing Drosophila, Drosophila suzukii (Matsumura) (Diptera: Drosophilidae)

Laboratory experiments were conducted to determine larval movement of the spotted wing drosophila (Drosophila suzukii Matsumura). Movement of larvae outside of the wild blueberry fruit (Vaccinium angustifolium Alton) can occur after exhausting fruit food resources prior to completion of development or just prior to pupation. We found that when provided a choice larvae select moist compared to dry environments both in plastic arenas providing only filter paper for shelter and in a soil filled petri dishes. Movement was usually limited to less than 7.5 cm in the soil from a release point. An exponential decay model suggests that only 0.1% of a larval population will move as far as 17.5 cm. Results of our study suggest that while larvae move readily, they have minimal ability to avoid localized xeric soil micro-climatic conditions through movement. However, they will select less stressful moist soil environments.