Animals in many phyla are adapted to and thrive in the constant darkness of subterranean environments. To do so, cave animals have presumably evolved mechano- and chemosensory compensations to the loss of vision, as is the case for the blind characiform cavefish, Astyanax mexicanus. Here, we systematically assessed the olfactory capacities of cavefish and surface fish of this species in the lab as well as in the wild, in five different caves in northeastern Mexico, using an olfactory setup specially developed to test and record olfactory responses during fieldwork. Overall cavefish showed lower (i.e., better) olfactory detection thresholds than surface fish. However, wild adult cavefish from the Pachón, Sabinos, Tinaja, Chica and Subterráneo caves showed highly variable responses to the three different odorant molecules they were exposed to. Pachón and Subterráneo cavefish showed the highest olfactory capacities, and Chica cavefish showed no response to the odors presented. We discuss these data with regard to the environmental conditions in which these different cavefish populations live. Our experiments in natural settings document the diversity of cave environments inhabited by a single species of cavefish, A. mexicanus, and highlight the complexity of the plastic and genetic mechanisms that underlie cave adaptation.

中文翻译：

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居住在不同洞穴中的墨西哥Astyanax穴居鱼种群嗅觉反应和技能的多样性

许多门的动物都适应并在不断地下环境中成长的环境中成长。为此，洞穴动物可能已经进化出对视力丧失的机械和化学感官补偿，就像盲目Characiform洞穴鱼Astyanax mexicanus的情况一样。。在这里，我们使用专门开发用于测试和记录野外工作期间嗅觉反应的嗅觉设置，系统地评估了该物种在实验室以及野外在墨西哥东北部五个不同洞穴中的洞穴鱼和表面鱼类的嗅觉能力。总体而言，洞穴鱼的嗅觉检测阈值比表面鱼低（即更好）。但是，来自Pachón，Sabinos，Tinaja，Chica和Subterráneo洞穴的成年野生cave鱼对它们所接触的三种不同的气味分子表现出高度可变的响应。Pachón和Subterráneo穴居鱼显示出最高的嗅觉能力，而Chica穴居鱼对出现的气味没有反应。我们讨论了有关这些不同的穴居鱼类种群所生活的环境条件的数据。墨西哥曲霉（A. mexicanus），并强调了适应洞穴的塑性和遗传机制的复杂性。