Program in Ecology and Evolutionary Biology, Department of Biological Sciences, University of Arkansas, AR 72701, USA; Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä 40014, Finland.
Program in Ecology and Evolutionary Biology, Department of Biological Sciences, University of Arkansas, AR 72701, USA.
J Insect Physiol. 2014 Feb;61:16-24. doi: 10.1016/j.jinsphys.2013.12.004. Epub 2013 Dec 25.
Sexual selection within populations can play an important role in speciation when divergence in mating signals and their corresponding preferences occur along different coevolutionary trajectories in different populations. In insects, one potential target of sexual selection is the blend of cuticular hydrocarbons (CHCs), which often show intra- and interspecific variation, sexual dimorphism and may act as pheromones. In Drosophila montana, a cold-adapted, circumboreal member of the Drosophila virilis species group, flies from different populations have been found to show significant premating isolation as well as variation in male mating signal (song) and female preference. While the role of male courtship song in mate choice has been studied extensively, CHCs in this species have received little attention. In this study, we identified most of the CHCs found on the cuticle of D. montana and characterized population divergence and sexual dimorphism of CHC profiles among flies established from three natural populations - one European and two North American. We also studied their potential role as pheromones by analyzing CHCs of flies used in female-choice mating experiments. We report significant population×sex effects on CHC profiles, as well as significant relationships between some CHC principal components and particular mating behaviours, such as female attractiveness and male mating success, providing evidence that CHCs may play a role in mate choice in this species. The study also provides evidence for variation in the degree to which CHCs play a role in chemical communication among these populations, which may have an influence on the speciation process itself, and could be due to variation in interactions with other closely-related species that occur sympatrically with D. montana in some, but not other, parts of its distribution.
种群内的性选择在物种形成中起着重要作用，当交配信号及其相应偏好沿着不同的协同进化轨迹在不同种群中发生分歧时。在昆虫中，性选择的一个潜在目标是表皮碳氢化合物（CHCs）的混合物，它通常表现出种内和种间变异、性别二态性，并且可能作为信息素发挥作用。在适应寒冷的环北极果蝇属 Drosophila montana 中，来自不同种群的果蝇被发现存在显著的交配前隔离以及雄蝇交配信号（歌声）和雌蝇偏好的变化。虽然雄蝇求偶歌声在配偶选择中的作用已经得到了广泛的研究，但该物种的 CHC 却很少受到关注。在这项研究中，我们鉴定了 D. montana 表皮上发现的大多数 CHC，并描述了来自三个自然种群（一个欧洲种群和两个北美种群）的果蝇的种群分歧和 CHC 图谱的性别二态性。我们还通过分析用于雌性选择交配实验的果蝇的 CHC，研究了它们作为信息素的潜在作用。我们报告了 CHC 图谱存在显著的种群×性别效应，以及一些 CHC 主要成分与特定交配行为之间存在显著关系，例如雌性吸引力和雄性交配成功率，这为 CHC 可能在该物种的配偶选择中发挥作用提供了证据。该研究还为 CHC 在这些种群的化学通讯中发挥作用的程度存在差异提供了证据，这可能对物种形成过程本身产生影响，并且可能是由于与其他密切相关的物种相互作用的变化，这些物种在 D. montana 的一些分布区域与 D. montana 共存，但在其他分布区域则没有。
