Data from: Reproductive character displacement of epicuticular compounds and their contribution to mate choice in Drosophila subqinaria and D. recens

Interactions between species can alter selection on sexual displays used in mate choice within species. Here we study the epicuticular pheromones of two Drosophila species that overlap partially in geographic range and are incompletely reproductively isolated. D. subquinaria shows a pattern of reproductive character displacement against D. recens, and partial behavioral isolation between conspecific sympatric vs. allopatric populations, whereas D. recens shows no such variation in mate choice. First, using manipulative perfuming experiments, we show that females use pheromones as signals for mate discrimination both between species and among populations of D. subquinaria. Second, we show that patterns of variation in epicuticular compounds, both across populations and between species, are consistent with those previously shown for mating probabilities: pheromone compositions differ between populations of D. subquinaria that are allopatric vs. sympatric with D. recens, but are similar across populations of D. recens regardless of overlap with D. subquinaria. We also identify differences in pheromone composition among allopatric regions of D. subquinaria. In sum, our results suggest that epicuticular compounds are key signals used by females during mate recognition, and that these traits have diverged among D. subquinaria populations in response to reinforcing selection generated by the presence of D. recens.

物种间的相互作用可改变物种内部择偶过程中性展示所承受的选择压力。本研究针对两种地理分布部分重叠、生殖隔离不完全的果蝇属（Drosophila）物种的表皮信息素（epicuticular pheromones）展开分析。拟奎果蝇（D. subquinaria）表现出针对堪萨斯果蝇（D. recens）的生殖特征置换现象，且其同种同域种群与异域种群间存在部分行为生殖隔离；而堪萨斯果蝇（D. recens）的择偶行为未出现此类变异。其一，通过控制性涂香实验，本研究证实雌性果蝇可利用信息素作为信号，在物种间以及拟奎果蝇的种群间开展交配识别。其二，本研究发现，跨种群与物种间的表皮化合物变异模式与此前报道的交配概率模式一致：与堪萨斯果蝇同域分布的拟奎果蝇种群，其信息素组成与异域种群存在显著差异；而无论是否与拟奎果蝇重叠分布，堪萨斯果蝇各种群的信息素组成均无明显差异。此外，本研究还发现拟奎果蝇不同异域区域的种群间，信息素组成亦存在差异。综上，本研究结果表明，表皮化合物是雌性果蝇完成配偶识别的关键信号；这类性状因堪萨斯果蝇存在所引发的强化选择压力，在拟奎果蝇的不同种群间发生了分化。