Wing imaginal discs from third instar D. melanogaster larvae harbouring the following transgenes: (a) hh-Gal4, UAS-riq and ex-lacZ; (b) en-Gal4, UAS-riq and th-lacZ; (c) hh-Gal4, UAS-riq and ban-lacZ; (d) hh-Gal4, UAS-mnb and ex-lacZ; (e), en-Gal4, UAS-riqRi and th-lacZ; and (f) en-Gal4, UAS-mnbRi and th-lacZ. Yki activity (grey in a-f) was reported by ex-lacZ (a and d), th-lacZ (b, e and f) or ban-lacZ (c). All transgenes were expressed in the posterior compartment of wing imaginal discs; Cubitus interruptus (Ci) expression (red in a’-f’) marked the anterior compartment. Merged images are shown in (a”-f”).