Department of Biology, Barnard College, Columbia University, New York, NY, United States.
Evolution. 2023 Jun 1;77(6):1396-1407. doi: 10.1093/evolut/qpad064.
Cryptic male mate choice occurs when males differentially allocate resources to females during or after copulation. When male resources are limited, males may benefit by strategically allocating more resources toward higher-quality females. In the fruit fly, Drosophila melanogaster, males mate for longer and may transfer more sperm and more seminal proteins when they mate with larger females compared with smaller females. It is unclear, however, whether this increased investment in large females has any impact on the males' later matings. We mated D. melanogaster males sequentially to females of large or small body size in all possible combinations to test whether cryptic male mate choice for large females is costly to the males' subsequent matings. Second matings were shorter for males compared with their first matings, but there were no differences in fecundity between females mated first or second by a male. Interestingly, male success at defensive sperm competition declined between his first and second matings only when his first mating had been with a large female. This suggests that the higher initial investment in large females reduced male postcopulatory success in their subsequent matings. Cryptic male mate choice may carry underappreciated costs to males that could limit their reproductive potential.
当雄性在交配期间或之后对雌性进行资源差异化分配时，就会出现隐性雄性择偶。当雄性资源有限时，它们可能会通过策略性地将更多资源分配给高质量的雌性来获益。在黑腹果蝇（Drosophila melanogaster）中，雄性的交配时间更长，与较小的雌性相比，它们与较大的雌性交配时可能会转移更多的精子和更多的精液蛋白。然而，这种对大型雌性的投资增加是否会对雄性的后续交配产生任何影响尚不清楚。我们将 D. melanogaster 雄性与体型较大或较小的雌性按所有可能的组合进行连续交配，以测试雄性对大型雌性的隐性择偶是否对其后续交配有代价。与第一次交配相比，第二次交配的雄性持续时间更短，但与第一次或第二次交配的雌性的繁殖力没有差异。有趣的是，只有当雄性的第一次交配对象是体型较大的雌性时，它在防御性精子竞争中的成功才会从第一次交配到第二次交配而下降。这表明，对大型雌性的初始投资更高，会降低雄性在后续交配中的交配后成功度。隐性雄性择偶可能会给雄性带来未被充分认识的代价，从而限制它们的繁殖潜力。
