Comparison of Female Drosophila suzukii (Matsumura) Reproductive Status Captured with Fermentation-Based Baits Traps and on Fruit

Drosophila suzukii (Matsumura), the spotted winged drosophila, is a polyphagous invasive species that has spread throughout North America since its initial detection in 2008. Females use their serrated ovipositor to lay eggs in undamaged, harvestable fruit, causing large economic losses and crippling integrated pest management programs in many fruit crops. Available monitoring traps with fermentation baits such as yeast/sugar are not accurate at predicting fly populations in fields. Because yeasts provide essential nutrients for Drosophila reproduction, reproductively immature females may visit traps to mate and/or obtain nutrients for egg maturation, while mature, egg-laying females may be less attracted to traps when ripe fruit is present. Therefore, our objective was to determine if the reproductive status of females collected in traps, on the outside of traps, and on fruit differed. Females were collected at two locations in North Carolina in 2013 and 2014 and were ranked based on the presence/absence of mature eggs and the number of mature eggs present. Females collected on fruit had more mature eggs than females collected on or within traps. This study has implications for bait selection and use and the development of more effective monitoring tools in the future.