How do red-eyed treefrog embryos sense motion in predator attacks? Assessing the role of vestibular mechanoreception

The widespread ability to alter hatching timing in response to environmental cues can serve as a defense against threats to eggs. Arboreal embryos of red-eyed treefrogs, Agalychnis callidryas, hatch up to 30% prematurely to escape predation. This escape-hatching response is cued by physical disturbance of eggs during attacks, including vibrations or motion, and thus depends critically on mechanosensory ability. Predator-induced hatching appears later in development than flooding-induced, hypoxia-cued hatching; thus, its onset is not constrained by the development of hatching ability. It may, instead, reflect the development of mechanosensor function. We hypothesize that vestibular mechanoreception mediates escape-hatching in snake attacks, and that the developmental period when hatching-competent embryos fail to flee from snakes reflects a sensory constraint. We assessed the ontogenetic congruence of escape-hatching responses and an indicator of vestibular function, the vestibulo-ocular...

生物普遍具备响应环境信号调整孵化时机的能力，以此作为抵御卵期生存威胁的防御策略。红眼雨滨蛙（Agalychnis callidryas）的树栖胚胎可提前至多30%的孵化时长以逃避捕食者。该逃逸孵化行为由捕食攻击过程中卵体受到的物理扰动（包括振动或位移）触发，因此高度依赖机械感知（mechanosensory）能力。捕食者诱导的孵化行为在发育时序上晚于洪水缺氧诱导的孵化行为，因此其启动不受孵化能力发育进程的限制，反而可能反映机械感受器功能的成熟。我们提出如下假说：前庭机械感受器（vestibular mechanoreception）介导了蛇类攻击引发的逃逸孵化行为，而具备孵化能力的胚胎未能在蛇类攻击时逃逸的发育阶段，反映了一种感知约束。我们评估了逃逸孵化反应与前庭功能指标——前庭眼反射（vestibulo-ocular...）的发育一致性。