Fig. 1.

Divergence in periphallic structures in the D. simulans clade and its relationship to the outgroup D. melanogaster (2). (A) Schematic representation of the male analia and external genitalia (posterior view). Posterior lobes are illustrated as dissected away on the right-hand side, in order to facilitate visualization of the claspers (outlined in orange), which are typically covered by the posterior lobes. While the shape and size of the posterior lobes is species-specific, the claspers and anal plates are very similar between D. simulans and D. sechellia, which are smaller and have less bristles than those of D. mauritiana and D. melanogaster. In addition, the clasper bristles of D. mauritiana are shorter and thicker than those of the other three species (19, 20, 48). (B–E) Scanning electron micrographs of external male genitalia (B and C) and dissected claspers (D and E) of Dmau D1 and Dsim w⁵⁰¹, respectively. (Scale bars, 50 μm.)