Data from: Significance of constraints on genital coevolution: why do female Drosophila appear to cooperate with males by accepting harmful matings?

The mechanisms driving the coevolution of male and female genital morphologies are still debated. Female genitalia in Drosophila species bear membranous “pouches” or hardened “shields,” which the male genital armature contact during copulation. Although shield-like structures likely serve to “resist” harmful mating, some authors have suggested that soft pouches, which do not prevent male genitalia from inflicting wounds, represent a congruent sensory organ. To elucidate the evolutionary forces responsible for the development of such organs, I examined the effects of artificial damage to various genital parts of female D. erecta on reproductive success. Despite a high survival rate among females, damage to the ovipositor plate resulted in frequent failure of insemination and in the embedment of eggs into the substrate. Damage to the vaginal shield resulted in increased mortality and frequent failure of egg embedment, with an egg blocking the vagina under the damaged shield in some females. Wounding of the pouch had less of an effect on both mating and oviposition success, suggesting that the structure “lures” the male trauma-causing organs to areas where the resultant wounds do not interfere with insemination or oviposition. These data show that the dual functions of female genitalia (mating and oviposition) mediate genital coevolution.驱动雌雄生殖器形态协同演化的相关机制至今仍存在诸多争议。果蝇属（Drosophila）物种的雌性生殖器带有膜质"囊袋"或硬化"盾片"，雄性生殖器的骨化结构会在交配过程中与之接触。尽管这类盾状结构可能用于"抵御"有害交配行为，但已有学者提出，无法阻止雄性生殖器造成创伤的柔软囊袋实则是一类协同适配的感觉器官。为阐明驱动这类生殖器演化的选择压力，本研究对雌性直立果蝇（Drosophila erecta）的不同生殖器部位实施人工损伤，并检测其对繁殖成功率的影响。尽管雌性个体整体存活率较高，但对产卵器板（ovipositor plate）造成损伤会频繁引发授精失败，同时导致卵无法成功嵌入产卵基质。对阴道盾（vaginal shield）造成损伤则会使雌性死亡率上升，且频繁出现卵嵌入失败的情况，部分雌性的卵会卡在受损盾片下方的阴道内。对囊袋造成创伤则对交配和产卵成功率的影响相对微弱，这表明该结构可"引诱"雄性的创伤性生殖器结构至不会干扰授精或产卵的区域。本研究结果证实，雌性生殖器的双重功能（交配与产卵）介导了生殖器的协同演化进程。