Department of Biology, New York University, USA.
Curr Biol. 2018 Jan 22;28(2):R60-R64. doi: 10.1016/j.cub.2017.12.011.
Life in caves means life in perpetual darkness. This has two dramatic effects on animals: it eliminates the need to see and reduces the availability of food as there is no local photosynthesis. Food availability for cave dwellers is often seasonal, episodic or unscheduled. Like other cave animals, fish species adapted for cave life exhibit a suite of sensory, morphological, physiological and behavioral traits that are shared among species from phylogenetically distant families. Most cave fishes are entirely or partially blind. The most extreme of them, the obligatory cave-dwelling fish that spend their entire life in caves, are the subject of this primer. At present, over 200 such cavefish species have been described, and all of them have evolved independently from surface ancestors. Thus, each cavefish species is a replicate of the same natural experiment, testing the evolutionary response of a sighted surface fish to the absence of light and the limitations on food in a subterranean environment. The evolutionary responses converge on loss of eyes and pigmentation and the augmentation of other senses, such as taste, smell or mechanosensation, as well as a more efficient metabolism, changes in feeding behavior, altered activity levels, loss of circadian rhythmicity and increased wakefulness. However, not all of these troglomorphic traits are present in every cavefish species.
洞穴中的生活意味着永恒的黑暗。这对动物有两个显著的影响：它消除了视觉的需求，并减少了食物的供应，因为没有局部的光合作用。洞穴生物的食物供应往往是季节性的、偶发性的或无规律的。与其他洞穴动物一样，适应洞穴生活的鱼类表现出一系列的感觉、形态、生理和行为特征，这些特征在来自不同进化家族的物种中是共同的。大多数洞穴鱼类都是完全或部分失明的。其中最极端的是那些必须生活在洞穴中的洞穴鱼，它们的一生都在洞穴中度过，这是本入门书的主题。目前，已经描述了 200 多种这样的洞穴鱼类，它们都是从地表祖先那里独立进化而来的。因此，每一种洞穴鱼类都是同一个自然实验的复制品，检验了有视力的地表鱼类在没有光和地下环境中食物有限的情况下的进化反应。进化反应集中在眼睛和色素的丧失以及其他感觉（如味觉、嗅觉或机械感觉）的增强，以及更有效的新陈代谢、摄食行为的改变、活动水平的降低、昼夜节律的丧失和觉醒时间的增加。然而，并非所有这些洞穴特化特征都存在于每一种洞穴鱼类中。
