Plath Martin, Seggel Uta, Burmeister Heike, Heubel Katja U, Schlupp Ingo
Unit of Evolutionary Biology and Systematic Zoology, Institute for Biochemistry and Biology, University of Potsdam, Karl-Liebknecht Str. 24-25, 14476 Potsdam, Germany.
Naturwissenschaften. 2006 Mar;93(3):103-9. doi: 10.1007/s00114-005-0072-z. Epub 2006 Feb 14.
Atlantic mollies (Poecilia mexicana) inhabit a variety of surface habitats, but they also occur in a sulfur cave in southern Mexico. We examined male mate choice relative to female body size in the cave population and in the most closely related surface-dwelling population from a nearby river. Males from both populations were either light- or dark-reared and could choose between two differently sized females either on the basis of visual cues in light or on the basis of solely nonvisual cues in darkness. Sexual preferences were estimated from the degree of association. Cave molly males always showed a preference for the larger female, both in light and in darkness. Among the surface males, only light-reared males showed a preference in the visual cues test, but not in darkness. In a control experiment, we demonstrated that male association preferences directly translate into actual mating preferences. Apparently, using visual cues for mate choice is the ancestral state in this system, and using nonvisual cues has evolved as a novel trait in the cave population. We discuss the evolution of nonvisual male mate choice in the context of changed environmental conditions, namely the absence of light, hypoxia, and toxic hydrogen sulfide in the cave.
大西洋帆鳉（Poecilia mexicana）栖息于各种表层栖息地，但在墨西哥南部的一个硫洞中也有它们的身影。我们研究了洞穴种群以及附近河流中关系最为密切的表层栖息种群中雄性相对于雌性体型的配偶选择情况。来自这两个种群的雄性分别在明亮或黑暗环境中饲养，它们可以根据明亮环境中的视觉线索或仅根据黑暗环境中的非视觉线索在两只不同体型的雌性之间做出选择。根据关联程度来估计性偏好。洞穴帆鳉雄性在明亮和黑暗环境中总是表现出对较大雌性的偏好。在表层雄性中，只有在明亮环境中饲养的雄性在视觉线索测试中表现出偏好，而在黑暗环境中则没有。在一项对照实验中，我们证明了雄性的关联偏好直接转化为实际的交配偏好。显然，在这个系统中，利用视觉线索进行配偶选择是原始状态，而利用非视觉线索则是洞穴种群中进化出的一种新特征。我们在环境条件发生变化的背景下讨论非视觉雄性配偶选择的进化，即洞穴中缺乏光线、缺氧以及存在有毒的硫化氢。
