01939nas a2200169   4500008004100000022002500041245010500066210006900171260001600240300001000256490000600266520139300272100002401665700002101689700002001710856003901730       2021                        eng d  a2056-3744, 2056-374400aFrequent origins of traumatic insemination involve convergent shifts in sperm and genital morphology0 aFrequent origins of traumatic insemination involve convergent sh  cDec-30-2021  a63-820 v63 a<p>Traumatic insemination is a mating behavior during which the (sperm) donor uses a traumatic intromittent organ to inject an ejaculate through the epidermis of the (sperm) recipient, thereby frequently circumventing the female genitalia. Traumatic insemination occurs widely across animals, but the frequency of its evolution, the intermediate stages via which it originates, and the morphological changes that such shifts involve remain poorly understood. Based on observations in 145 species of the free-living flatworm genus Macrostomum, we identify at least nine independent evolutionary origins of traumatic insemination from reciprocal copulation, but no clear indication of reversals. These origins involve convergent shifts in multivariate morphospace of male and female reproductive traits, suggesting that traumatic insemination has a canalizing effect on morphology. We also observed sperm in both the sperm receiving organ and within the body tissue of two species. These species had intermediate trait values indicating that traumatic insemination evolves through initial internal wounding during copulation. Finally, signatures of male-female coevolution of genitalia across the genus indicate that sexual selection and sexual conflict drive the evolution of traumatic insemination, because it allows donors to bypass postcopulatory control mechanisms of recipients.</p>
1 aBrand, Jeremias, N.1 aHarmon, Luke, J.1 aSchärer, Lukas  uhttp://dx.doi.org/10.1002/evl3.268