Data from: Local adaptation to developmental density does not lead to higher mating success in Drosophila melanogaster

In this study, we investigate the effect of local adaptation to developmental density on male mating success in laboratory populations of Drosophila melanogaster. Mating success is known to be influenced by body condition which can in turn be influenced by local adaptation. We test the hypothesis that males adapted to a given environment have higher mating success when assayed in that environment. We used males selected for adaptation to high larval density and their controls which are reared at low larval density. We grew assay males in low and high densities while the focal females (raised at low larval density) used for the experiment belonged to the common ancestor of selected and control populations. We considered selected males grown at high density and control males grown at low density as “adapted”. Similarly we considered selected males grown at low density and control males grown at high density as “non-adapted”. Selected male belonging to a given treatment (larval density) was made to compete with control male of the same treatment for mating with ancestral female. We quantified components of reproductive fitness: mating latency, copulation duration, mating success and number of progeny sired by the “adapted” and “non-adapted” males. The results show that local adaptation does not lead to higher mating success in populations adapted to their own larval rearing environment.

本研究以实验室种群中的黑腹果蝇（Drosophila melanogaster）为研究对象，探究发育密度的局部适应对雄性交配成功率的影响。已知交配成功率受个体身体状况影响，而身体状况本身又可受到局部适应的调控。我们验证了如下假说：适应特定环境的雄性果蝇，在该环境中被检测时具有更高的交配成功率。我们选取了经选育以适应高幼虫密度的雄性果蝇作为实验组，以及在低幼虫密度下饲养的雄性果蝇作为对照组。我们在低、高两种幼虫密度下培养供试雄性果蝇，而本实验所用的焦点雌性果蝇（均在低幼虫密度下饲养）则来自实验组与对照组的共同祖先种群。我们将在高幼虫密度下培养的实验组雄性，以及在低幼虫密度下培养的对照组雄性定义为“适应型”个体；同理，将在低幼虫密度下培养的实验组雄性，以及在高幼虫密度下培养的对照组雄性定义为“非适应型”个体。将来自某一处理组（幼虫密度）的实验组雄性与同处理组的对照组雄性一同竞争，以与祖先雌性果蝇完成交配。我们量化了繁殖适合度的多项指标：交配潜伏期、交配持续时长、交配成功率，以及“适应型”与“非适应型”雄性所育的子代数量。实验结果表明，在适应自身幼虫饲养环境的种群中，局部适应并未提升雄性的交配成功率。