An eyespot that “blinks”: an open and shut case of eye mimicry in <i>Eumorpha</i> caterpillars (Lepidoptera: Sphingidae)

We describe the final instars of two tropical Sphingidae caterpillars – <i>Eumorpha phorbas</i> and <i>Eumorpha labruscae</i> – from Area de Conservacion Guanacaste, northwestern Costa Rica, whose anal horn has become a posterior eyespot structure capable of rapid palpitation. When approached or harassed, the caterpillars palpitate this eyespot and produce the effect of a blinking vertebrate eye. We propose that this “blinking” is an extension of eye mimicry or at least draws attention to the eyespot, functioning to startle or intimidate would-be predators. As snakes lack eyelids and do not blink, this suggests that the blinking eye represents a more generalized (or possibly mammalian) eye. Eyespot “blinking” is probably controlled by the same musculature used to wave the anal horn in earlier instars. The extent to which this eyespot is perceived as a blinking eye, and the degree of protection from the caterpillars' suite of potential predators, remain to be discovered.我们记述了采自哥斯达黎加西北部瓜纳卡斯特保护区（Area de Conservacion Guanacaste）的两种热带天蛾科（Sphingidae）幼虫的末龄阶段——<i>Eumorpha phorbas</i>与<i>Eumorpha labruscae</i>：这类幼虫的尾角已特化为可快速搏动的后侧眼斑结构。当受到靠近或惊扰时，幼虫会使该眼斑搏动，营造出脊椎动物眼睛眨动的视觉效果。我们提出，这种“眨动”是眼斑拟态的延伸，或至少能够吸引天敌对该眼斑的注意力，从而起到威慑或吓退潜在捕食者的作用。由于蛇类没有眼睑且无法眨动眼睛，这表明该“眨动的眼睛”所模拟的是更具普遍性（或可能为哺乳类）的眼睛。眼斑的“眨动”大概率由幼虫早期用于摆动尾角的同一组肌肉调控。目前，该眼斑被识别为眨动眼睛的程度，以及该结构对幼虫所面临的各类潜在捕食者的防护效果，仍有待进一步研究。