Or92a gal4

All strains developed for this study are listed in Supplementary Table 2. Aop-CD4:spGFP11 and UAS-CD4:spGFP1–10 were gifts of K. Scott. Drivers GH146-Gal4, GH146-LexA, GH146-QF, Orco-Gal4, Orco-LexA, Or92a-Gal4, GR21a-Gal4, VGlut-Gal4, MB247-Gal4 and MB247-LexA are available from the Bloomington Stock Center. IR84a-LexA was a gift from R. Benton. panR8-Gal4 (ref. 38 (link); a combination of rh5-Gal4+rh6-Gal4) and Tm5c-LexA10 (link) have been previously published, as have Ir93a-LexA9 (link) and VT40053-Gal4 (ref. 9 (link)). Flies used for Fig. 1 came from regular laboratory fly vials, were not sexed and were 2–6 days old. Flies used in Fig. 2 were all females (due to constraints of the genetic cross), and 6–7 days old—this is because the tdTomato signal was difficult to detect in younger flies.

All flies were raised on standard cornmeal agar medium, under 60% humidity and a 12-h light/12-h dark cycle at 25 °C. The Or10a-Gal4 (BL9944), Or42b-Gal4 (BL9971), Or43a-Gal4 (BL9974), Or49b-Gal4 (BL9986), Or56a-Gal4 (BL9988 and 23896), Or82a-Gal4 (BL23125), Or85a-Gal4 (BL23133), Or92a-Gal4 (BL23140), UAS-Orco (BL23145), Orco^{1 (link)} (BL23129), Orco^{2 (link)} (BL23130), UAS-TNT (BL28837 and 28997), UAS-TNT (inactive, BL28844), UAS-GCaMP6m (BL42748 and 42750), UAS-GCaMP6f (BL42747), and UAS-H134R-ChR2 (BL28995) flies were from the Bloomington Stock Center. UAS-mCD8-GFP was a gift from Dr. Chris Potter at the Johns Hopkins University School of Medicine, USA. UAS-P2X₂ was a gift from Dr. Zuoren Wang at the Institute of Neuroscience, China. The flies have been backcrossed for seven generations to a laboratory w¹¹¹⁸ strain.