Thiagavel Jeneni, Cechetto Clément, Santana Sharlene E, Jakobsen Lasse, Warrant Eric J, Ratcliffe John M
Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, ON, M5S 3B2, Canada.
Department of Biology, University of Southern Denmark, Campusvej 55, 5230, Odense C, Denmark.
Nat Commun. 2018 Jan 8;9(1):98. doi: 10.1038/s41467-017-02532-x.
Substantial evidence now supports the hypothesis that the common ancestor of bats was nocturnal and capable of both powered flight and laryngeal echolocation. This scenario entails a parallel sensory and biomechanical transition from a nonvolant, vision-reliant mammal to one capable of sonar and flight. Here we consider anatomical constraints and opportunities that led to a sonar rather than vision-based solution. We show that bats' common ancestor had eyes too small to allow for successful aerial hawking of flying insects at night, but an auditory brain design sufficient to afford echolocation. Further, we find that among extant predatory bats (all of which use laryngeal echolocation), those with putatively less sophisticated biosonar have relatively larger eyes than do more sophisticated echolocators. We contend that signs of ancient trade-offs between vision and echolocation persist today, and that non-echolocating, phytophagous pteropodid bats may retain some of the necessary foundations for biosonar.
蝙蝠的共同祖先为夜行性，具备动力飞行和喉部回声定位能力。这种情况意味着从一种不会飞、依赖视觉的哺乳动物向一种具备声呐和飞行能力的动物进行了平行的感官和生物力学转变。在这里，我们考虑导致采用声呐而非基于视觉的解决方案的解剖学限制和机遇。我们表明，蝙蝠的共同祖先眼睛太小，无法在夜间成功在空中捕食飞行昆虫，但听觉脑结构足以支持回声定位。此外，我们发现，在现存的食肉蝙蝠中（它们都使用喉部回声定位），那些声呐相对不那么复杂的蝙蝠比声呐更复杂的蝙蝠眼睛相对更大。我们认为，视觉和回声定位之间古老权衡的迹象至今仍然存在，并且不使用回声定位的食草翼手目蝙蝠可能保留了一些声呐所需的基础。
