Copulatory wounding in Drosophila melanogaster

Copulation can result in males inflicting wounds to the female genitalia,
so-called traumatic mating. Such wounds are potentially costly as they
could be entry points for infections, and they have been associated with a
shorter lifespan in insect species. In many species of insects, females
mate with more than one male, which leads to the question of whether the
number of matings affects the amount of genital damage that females suffer
from those matings. Here we test whether copulation frequency affects the
number or size of genital wounds in Drosophila melanogaster. Females who
mated twice had more genital wounds and a larger total area of wounding,
compared to females who mated once. However, females who refused to mate a
second time had a similar area of wounding as females who mated twice. We
found that wounds to the ventral abdomen also increased with increased
mating frequency. Our results show that polyandry can result in increased
female copulatory wounding in this species. The extent to which the wounds
are costly for females is currently unknown. Investigating genital and
abdominal wounds is crucial to a better understanding of the consequences
of sexual conflict and the selective pressures shaping mating behaviour.