Sexual selection protects against extinction

Reproduction through sex carries substantial costs, mainly because only half of sexual adults produce offspring. It has been theorized that these costs could be countered if sex allows sexual selection to clear the universal fitness constraint of mutation load. Under sexual selection, competition between (usually) males and mate choice by (usually) females create important intraspecific filters for reproductive success, so that only a subset of males gains paternity. If reproductive success under sexual selection is dependent on individual condition, which is contingent to mutation load, then sexually selected filtering through ‘genic capture’ could offset the costs of sex because it provides genetic benefits to populations. Here we test this theory experimentally by comparing whether populations with histories of strong versus weak sexual selection purge mutation load and resist extinction differently. After evolving replicate populations of the flour beetle Tribolium castaneum for 6 t...

有性生殖需承担高昂代价，其核心缘由在于仅半数参与有性繁殖的成年个体能够产生后代。有理论指出，若有性生殖可通过性选择破除突变负荷这一普适性适合度限制，便能抵消此类代价。在性选择过程中，（通常为雄性间的）竞争与（通常为雌性的）配偶选择构建了针对繁殖成功的关键种内筛选机制，最终仅少数雄性可获得父本资格。若性选择下的繁殖成功取决于个体状态——而个体状态又与突变负荷紧密相关——那么通过“基因捕获（genic capture）”实现的性选择筛选，能够为种群带来遗传收益，从而抵消有性生殖的代价。本研究通过实验对该理论进行验证：以赤拟谷盗（Tribolium castaneum）的重复繁殖种群为对象，对比经历强性选择与弱性选择的两类种群在清除突变负荷与抵御灭绝能力上的差异。研究人员已对该种群进行了6代……