Flexible polyandry in female flies is an adaptive response to infertile males
Flexible polyandry in female flies is an adaptive response to infertile males
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DOI：
10.1093/beheco/arz140
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发表时间：
2019-11-01
影响因子：
2.4
通讯作者：
Wedell, Nina
中科院分区：
文献类型：
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作者：
Sutter, Andreas;Travers, Laura M.;Wedell, Nina
不孕症在自然界中很常见，尽管它对个体健康有明显的影响。据预测，全球气温上升将降低生育力，雄性不育经常被用来调节害虫或疾病媒介种群。当雄性不育时，雌性可能会与多个雄性交配以确保受精，而雌性交配行为的变化反过来又会加强对雄性生育能力的选择。生育保障是一妻多夫制的一个潜在的广泛解释，但它是否以及如何实际上有助于一妻多夫制的演变尚不清楚。此外，男性生育率的下降是否会导致一妻多夫制的遗传增加，取决于女性是否对男性不育做出遗传反应或通过行为可塑性做出反应。在这里，我们实验性地操纵男性生育能力，通过热暴露在果蝇pseudobscura，并测试女性歧视不育男性之前和之后交配。使用同基因系，我们比较行为塑料与遗传固定的一妻多夫制的作用。我们发现，热暴露的男性不那么活跃和有吸引力，女性更有可能与这些男性交配后重新交配。再交配率随着生殖输出的减少而增加，表明雌性利用当前的精子储存阈值来做出动态的再交配决策。在与有生育能力的雄性再次交配后，雌性恢复正常的生育力水平。我们的研究结果表明，男性不育可以解释适应性灵活的一妻多夫制的演变，但不太可能导致遗传一妻多夫制的增加。
Infertility is common in nature despite its obvious cost to individual fitness. Rising global temperatures are predicted to decrease fertility, and male sterility is frequently used in attempts to regulate pest or disease vector populations. When males are infertile, females may mate with multiple males to ensure fertilization, and changes in female mating behavior in turn could intensify selection on male fertility. Fertility assurance is a potentially wide-spread explanation for polyandry, but whether and how it actually contributes to the evolution of polyandry is not clear. Moreover, whether a drop in male fertility would lead to a genetic increase in polyandry depends on whether females respond genetically or through behavioral plasticity to male infertility. Here, we experimentally manipulate male fertility through heat-exposure in Drosophila pseudoobscura, and test female discrimination against infertile males before and after mating. Using isogenic lines, we compare the roles of behaviorally plastic versus genetically fixed polyandry. We find that heat-exposed males are less active and attractive, and that females are more likely to remate after mating with these males. Remating rate increases with reduced reproductive output, indicating that females use current sperm storage threshold to make dynamic remating decisions. After remating with fertile males, females restore normal fecundity levels. Our results suggest that male infertility could explain the evolution of adaptively flexible polyandry, but is less likely to cause an increase in genetic polyandry.