Power D J, Holman L
Division of Evolution, Ecology & Genetics, Research School of Biology, Australian National University, Canberra, ACT, Australia.
J Evol Biol. 2015 May;28(5):1039-48. doi: 10.1111/jeb.12625. Epub 2015 Apr 18.
A major unsolved question in evolutionary biology concerns the relationship between natural and sexual selection. Sexual selection might augment natural selection, for example if mutations that harm female fecundity also reduce male mating success. Conversely, sexual selection might favour traits that impair naturally selected fitness components. We induced detrimental mutations in Callosobruchus maculatus beetles using X-ray irradiation and then experimentally measured the effect of precopulatory sexual selection on offspring number and survival rate. Sexual selection treatment had a negative effect on egg-to-adult survivorship, although the number of progeny reaching adulthood was unaffected, perhaps because eggs and juveniles that failed to develop lessened competition on the survivors. We hypothesize that the negative effect of sexual selection arose because sexually competitive males transmitted a smaller nuptial gift or carried alleles that conferred reduced survival. Although we found no evidence that sexual selection on males can purge alleles that are detrimental to naturally selected fitness components, such benefits might exist in other environmental or genetic contexts.
进化生物学中一个主要的未解决问题涉及自然选择和性选择之间的关系。性选择可能会增强自然选择，例如，如果损害雌性繁殖力的突变也会降低雄性的交配成功率。相反，性选择可能会青睐那些损害自然选择的适应性成分的性状。我们使用X射线辐射在黄斑豆象甲虫中诱导有害突变，然后通过实验测量交配前性选择对后代数量和存活率的影响。性选择处理对卵到成虫的存活率有负面影响，尽管达到成年期的后代数量不受影响，这可能是因为未能发育的卵和幼虫减少了对幸存者的竞争。我们推测，性选择的负面影响是由于具有性竞争力的雄性传递了较小的婚飞礼物，或者携带了导致存活率降低的等位基因。尽管我们没有发现证据表明对雄性的性选择可以清除对自然选择的适应性成分有害的等位基因，但在其他环境或遗传背景下可能存在这样的好处。
