Traumatic mating increases anchorage of mating male and reduces female remating duration and fecundity in a scorpionfly species
Tong, Xin et al. (2021), Traumatic mating increases anchorage of mating male and reduces female remating duration and fecundity in a scorpionfly species, Dryad, Dataset, https://doi.org/10.5061/dryad.bnzs7h49h
Traumatic mating is the male wounding his mate during mating using specialized anatomy. However, why males have evolved to injure their mates during mating remains poorly understood. We studied the traumatic mating and copulatory wounding of the mate’s genitalia by the male in the scorpionfly Dicerapanorpa magna to determine its effects on male and female fitness. The results showed that the sharp teeth on the male gonostyli penetrate the female genitalia and cause copulatory wounds, and the size of the area of the wounds on the female genitals is positively related to the number of times females mated. When the injurious teeth were encased with low-temperature wax, preventing their penetration of the female’s genitalia during mating, male mating success and copulation duration were reduced significantly, indicating the importance of the teeth in allowing the male to secure copulation, remain in copula and effectively inseminate his mate. The remating experiments showed that the traumatic mating had little effect on the female mating refractory period (time between matings), but significantly reduced the female remating duration with subsequent males. The reduction of the female remating duration likely benefits the first-mating male as he has a longer copulation duration, and thereby transfers more sperm into the female’s spermatheca. The copulatory wounds reduced female fecundity, but did not accelerate the timing of egg deposition by the female. This is likely the first report that traumatic mating can reduce the female remating duration through successive remating experiments in animals. Overall, our results provide evidence that traumatic mating in the scorpionfly helps increase the male’s anchoring control during mating and provides him advantage in sperm competition, but at the expense in lowering female fecundity.
National Natural Science Foundation of China, Award: 31672341