Drosophila suzukii is a destructive vinegar fly that causes hundreds of millions of dollars in economic losses per year. Monitoring traps are an important tool for estimating D. suzukii activity. Understanding differences in summer and winter morph D. suzukii behavior and response to trap placement could improve trapping programs. I found a 3.5℗ʻC difference in temperature where 25% of D. suzukii walked for summer and winter morphs when evaluating locomotion temperature thresholds. When evaluating trap position preferences in the laboratory, I found that placement of trap was the determining factor for where winter morph D. suzukii were captured and winter morph were 6 times more likely to be captured in a floor trap than an aerial trap. In the field, I found that aerial cup traps were most effective for summer trapping and cup traps placed on the ground were most effective for winter trapping. However, during mid-August I observed significantly more summer morph male flies captured in dome traps placed on or under leaf litter. Additionally, the aerial cup traps were the least selective for D. suzukii, capturing 89 times more non-target drosophilids than D. suzukii. My results provide insight into the behavioral differences between summer and winter morph D. suzukii. Furthermore, my data shows how season influences preferred trap position, and could lead to improved monitoring of D. suzukii.
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