In several animals, male genitalia create insemination wounds in areas outside the genital orifice of females. I report that such traumatic insemination (TI) occurs in the Drosophila bipectinata complex (Diptera: Drosophilidae) and illustrate a previously unknown evolutionary pathway for this behaviour. Flash fixation of mating pairs revealed the dual function of the paired claw-like basal processes, previously misidentified as a bifid aedeagus: (i) penetration of the female body wall near the genital orifice and (ii) sperm transfer into the genital tract through the wounds. Basal processes in closely related species (Drosophila ananassae and Drosophila pallidosa) also wounded females but did not transfer sperm; this represents a transitional state to TI as observed in the bipectinata complex. Copulatory wounding is suggested to occur in other allied species of the Drosophila melanogaster species group, including D. melanogaster. Ubiquitous sexual conflicts over mating may have led to the evolution of novel intromittent organs for insemination.

Males of several insect species inXict wounds on female genitalia during copulation. Such copulatory wounding also occurs in the fruit Xy Drosophila melanogaster Meigen, 1830, one of the most important model organisms. Using a Xash Wxation technique with mating pairs of D. melanogaster, I examined the use and functions of the male phallic organ within the female reproductive tract. Paired components of the phallic organ (gonopods and two pairs of branches of the basal processes of the aedeagus) opened sequentially, from outer to inner components, during copulation. The dorsal branches of the aedeagal basal processes pierced the intima of the female reproductive tract at the lateral shallow folds. Consequently, mated females usually had a pair of melanized patches from repaired copulatory wounds. The sites that were stabbed by the dorsal branches were also clutched on the outside of the female oviscape (ovipositor) by the posterior process, which is a component of the periphallic organ. These structures likely function together as a mateholding device. Male ejaculate labeled with rhodamine-B Xuorescent dye entered the copulatory wounds in D. eugracilis Bock and Wheeler (Univ Texas Publ 7213:1-102, 1972), a related species, but not in D. melanogaster.Thus, copulatory wounds may function as an entrance for male seminal chemicals into the female circulatory system in D. eugracilis, but might not in D. melanogaster.

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