Genital coupling and copulatory wounding in drosophila teissieri (diptera: Drosophilidae)

We report genital coupling of Drosophila teissieri Tsacas, 1971, a member of the Drosophila melanogaster species subgroup. The species subgroup consists of nine described species including the model organism Drosophila melanogaster Meigen, 1830. Despite numerous studies on the biology of this group, our understanding of the evolutionary significance of the diversity in their genital structures is limited. This study provides evidence that (i) during the copulation, which lasts 41.1 min, a paired male genital part (dorsal branches of the basal processes of the aedeagus) open after being inserted into the female reproductive tract, (ii) female D. teissieri have a pair of pockets on the dorsal side of their genitalia that receive bifurcated spines of the male genitalia (ventral branches of the basal processes of the aedeagus), and (iii) male genital parts, especially unique strong spines of the cerci, cause multiple copulatory wounds on membranous areas of the female genitalia. Within the established phylogeny of the D. melanogaster species subgroup, we discuss possible functions of and evolutionary transitions in these genital structures.