Am Nat. 2023 Apr;201(4):E56-E69. doi: 10.1086/723213. Epub 2023 Feb 2.
AbstractThe presence of same-sex sexual behavior across the animal kingdom is often viewed as unexpected. One explanation for its prevalence in some taxa is indiscriminate mating-a strategy wherein an individual does not attempt to determine the sex of its potential partner before attempting copulation. Indiscriminate mating has been argued to be the ancestral mode of sexual reproduction and can also be an optimal strategy given search costs of choosiness. Less attention has been paid to the fact that sex discrimination requires not just the attempt to differentiate between the sexes but also some discernible difference (a signal or cue) that can be detected. To address this, we extend models of mating behavior to consider the coevolution of sex discrimination and sexual signals. We find that under a wide range of parameters, including some with relatively minor costs, indiscriminate mating and the absence of sexual signals will be an evolutionary end point. Furthermore, the absence of both sex discrimination and sexual signals is always evolutionarily stable. These results suggest that an observable difference between the sexes likely arose as a by-product of the evolution of different sexes, allowing discrimination to evolve.
在动物界中，存在着同性性行为，这通常是出乎意料的。在某些分类群中，这种行为普遍存在的一种解释是滥交——一种个体在试图交配之前，不试图确定其潜在伴侣性别的策略。滥交被认为是性繁殖的原始模式，并且在考虑到选择性的搜索成本时，也是一种最佳策略。人们较少关注的一个事实是，性别歧视不仅需要尝试区分性别，还需要能够检测到一些可识别的差异（信号或线索）。为了解决这个问题，我们扩展了交配行为模型，以考虑性别歧视和性信号的共同进化。我们发现，在广泛的参数范围内，包括一些相对较小的成本参数，滥交和缺乏性信号将是一个进化的终点。此外，性别歧视和性信号的缺失总是进化稳定的。这些结果表明，两性之间的可观察到的差异可能是不同性别进化的副产品，从而允许歧视的进化。
