Spotted Wing Drosophila (SWD, Drosophila suzukii) Volunteer Monitoring Network Identification Guide 24 March 2011

Indentifying SWD adults from monitoring traps: 1. Compare fly size and shape to voucher specimens. Flies should be 2-3 mm in length. 2. Examine wings for spots. If a single spot is present near the end of each wing and forelegs have black bands, the fly is a male SWD. 3. If wings have no spot, examine the end of the abdomen to determine if the fly is male or female. If wings have more than one spot or a cloudy cross vein (Fig. 3), the fly is not a SWD. 4. If the fly is female, gently press on the abdomen to extrude to ovipositor. If the ovipositor is large and serrated (compare to vouchers), the fly is a female SWD. Male SWD

Figure 1. Non SWD wing (top) and male SWD wing (bottom).

Figure 2. Male SWD leg; note black bands on foreleg.

Figure 3. Male SWD on yellow sticky trap (circled, left), and several non SWD drosophilds. Note “cloudy cross vein” on far left and 3 spots on fly on right.

Figure 4. Non SWD male fly.

Female SWD

Figure 5. Non SWD female ovipositor (left) and SWD ovipositor (right), approximately 20x magnification.

Figure 6. Female SWD (left) and 2 non SWD drosophild females, right.