Flexible polyandry in female flies is an adaptive response to infertile males

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 fertilisation, and changes in female mating behaviour 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 behavioural 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 ...

尽管不育对个体适合度（fitness）存在显著的进化代价，但不育现象在自然界中却颇为普遍。全球气温升高预计会降低生物的生育能力，而雄性不育技术常被应用于害虫或疾病媒介（disease vector）种群的调控工作中。当雄性个体不育时，雌性可能会通过与多个雄性交配以保障受精（fertilisation）成功，而雌性交配行为的改变反过来又会强化对雄性生育能力的选择压力。生育保障（fertility assurance）是解释一妻多夫制（polyandry）广泛存在的潜在重要假说之一，但目前尚不清楚其是否以及如何真正推动了一妻多夫制的演化。此外，雄性生育能力下降是否会导致一妻多夫制在遗传层面的频率升高，取决于雌性对雄性不育的响应是通过遗传途径还是行为可塑性（behavioural plasticity）实现的。本研究以拟暗果蝇（Drosophila pseudoobscura）为实验材料，通过热暴露手段人为调控雄性生育能力，并检测雌性在交配前后对不育雄性的识别偏好。本研究利用同基因系（isogenic lines），对比其在……中的作用……