Fig. 3. TcBR-C is necessary for proper differentiation of pupal characters. Strong and mild phenotypes in animals that had been injected with TcBR-C dsRNA as fifth to seventh instar larvae are compared with wild-type. (A) Urogomphi in strongly affected animals are short, as in larvae, but elongated and forked, more like in pupae, upon mild TcBR-C RNAi treatment (a-e, yellow arrowheads; adults lack urogomphi). Larval pygopods (black arrow) disappear and genital papillae on the ninth abdominal segment develop (yellow arrows), although the eighth segment is abnormally enlarged after strong TcBR-C RNAi (asterisks). The female genital pore (black arrowheads), visible in its original intersegmental position (d) has migrated between the papillae in a mildly affected female (e). VII, the seventh abdominal sternum. Females shown in b, d and e. (B) Cuticle surface on abdominal sterna is smooth, as in larvae, upon strong TcBR-C RNAi, but shows the pupal-like surface in milder phenotypes (compare a with d, and b with e). The adult cuticle has rounded pits with sensillae (c). (C) Gin traps (gt) form above pupal abdominal spiracles (sp) but are absent in larvae, adults and in strong TcBR-C(RNAi) phenotypes (a-d; arrowheads mark presumptive gin trap positions). Weakly affected animals partially develop gin traps (e). (D) Larval stemmata (a) are replaced by compound eyes that differentiate during pupal stage (b). Ommatidia appear in TcBR-C(RNAi) animals, although they are irregularly spaced (arrows, compare d and e with b). (E) Antennae lose the larval character in TcBR-C(RNAi) animals, but, unlike those in pupae, develop the distal club and divisions between segments. (F) Separations between tarsal segments are clearer in strong TcBR-C(RNAi) than in pupae or mild phenotypes, and sharp double claws (arrowheads), similar to those of adults (c), are visible (d). Larval tarsi are unsegmented and bear a single claw (a). Anterior (A-D) and proximal (E,F) is to the left. Scale bars: 500 µm (Ac,Da,Dc,Fc); 200 µm (Aa,Ab,Ad,Ae,Ca,Db,Dd,De,Eb,Fa,Fb,Fe); 100 µm (Cb-e,Ea,Ec-e,Fd); 50 µm (Ba-e).