Crustaceans detect chemical stimuli in the environment with aesthetasc sensilla, which are located on their 1st antennae. With the transition to other environments, chemoreception faces physical challenges. To provide a deeper understanding of the relation between the morphology of olfactory organs and different lifestyles, we studied the peripheral olfactory system of three amphipod species, the marine Gammarus salinus, the blind subterranean freshwater species Niphargus puteanus, and the terrestrial Cryptorchestia garbinii. We compared the 1st and 2nd antennae of these species with respect to length and presence of aesthetascs and other sensilla. The females of N. puteanus reveal the longest 1st antennae in relation to body size. G. salinus shows the largest aesthetascs and the same relative length of the 1st antennae as male N. puteanus. C. garbinii has very short 1st antennae and reduced (putative) aesthetascs. Our findings show that the compensation of vision loss by olfaction cannot be generally assumed in animals from dark environments. Furthermore, the behaviour of C. garbinii indicates a chemosensory ability, despite the reduction of the 1st antennae. A comparison with other terrestrial crustaceans suggests that the loss of the olfactory sense on the 1st antennae in C. garbinii might be compensated with chemoreception by the 2nd antennae.

中文翻译：

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三种不同生活方式的端足类动物触角的比较分析。


甲壳类动物通过位于第一触角的审美感受器来检测环境中的化学刺激。随着向其他环境的过渡，化学感受面临着身体上的挑战。为了更深入地了解嗅觉器官的形态与不同生活方式之间的关系，我们研究了三种片脚类物种的外周嗅觉系统：海洋Gammarus salinus、盲性地下淡水物种Nipargus puteanus和陆地Cryptorchestia garbinii。我们比较了这些物种的第一和第二触角的长度以及审美和其他感觉器的存在。与体型相比，雌性 N. puteanus 的第一触角最长。 G. salinus 与雄性 N. puteanus 表现出最大的审美能力和相同的第一触角相对长度。 C. garbinii 的第一触角非常短，并且（假定的）审美能力降低。我们的研究结果表明，在黑暗环境中的动物中，通常不能假设嗅觉对视力丧失的补偿。此外，尽管第一触角减少，但 C. garbinii 的行为表明其具有化学感应能力。与其他陆生甲壳类动物的比较表明，C. garbinii 第一触角嗅觉的丧失可能通过第二触角的化学感受来补偿。