School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK
School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK.
Proc Biol Sci. 2018 Apr 25;285(1877). doi: 10.1098/rspb.2018.0303.
Strong sexual selection has been reported to both enhance and hinder the adaptive capacity and persistence of populations when exposed to novel environments. Consequently, how sexual selection influences population adaption and persistence under stress remains widely debated. Here, we present two empirical investigations of the fitness consequences of sexual selection on populations of the Indian meal moth, exposed to stable or gradually increasing temperatures. When faced with increasing temperatures, strong sexual selection was associated with both increased fecundity and offspring survival compared with populations experiencing weak sexual selection, suggesting sexual selection acts to drive adaptive evolution by favouring beneficial alleles. Strong sexual selection did not, however, delay extinction when the temperature became excessively high. By manipulating individuals' mating opportunities during fitness assays, we were able to assess the effect of multiple mating independently from the effect of population-level sexual selection, and found that polyandry has a positive effect on both fecundity and offspring survival under increasing temperatures in those populations evolving with weak sexual selection. Within stable temperatures, there were some benefits from strong sexual selection but these were not consistent across the entire experiment, possibly reflecting changing costs and benefits of sexual selection under stabilizing and directional selection. These results indicate that sexual selection can provide a buffer against climate change and increase adaptation rates within a continuously changing environment. These positive effects of sexual selection may, however, be too small to protect populations and delay extinction when environmental changes are relatively rapid.
强烈的性选择既被报道可以增强也可以阻碍种群在面对新环境时的适应能力和持久性。因此，性选择如何影响压力下的种群适应和持久性仍然存在广泛的争议。在这里，我们展示了两个关于印度粉螟种群在稳定或逐渐升高的温度下经历性选择的适应性后果的实证研究。当面临温度升高时，与经历弱性选择的种群相比，强烈的性选择与更高的繁殖力和后代存活率相关，这表明性选择通过有利于有利等位基因来促进适应性进化。然而，当温度过高时，强烈的性选择并没有延迟灭绝。通过在适应性测定期间操纵个体的交配机会，我们能够独立于群体水平的性选择来评估多次交配的效果，并发现在经历弱性选择的种群中，多配偶制对繁殖力和后代存活率在温度升高的情况下都有积极影响。在稳定的温度下，强烈的性选择有一些好处，但在整个实验中并不一致，这可能反映了在稳定选择和定向选择下性选择的成本和收益的变化。这些结果表明，性选择可以为应对气候变化提供缓冲，并在不断变化的环境中提高适应速度。然而，性选择的这些积极影响可能太小，无法在环境变化相对较快时保护种群并延迟灭绝。
