Hoy R, Nolen T, Brodfuehrer P
Section of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853.
J Exp Biol. 1989 Sep;146:287-306. doi: 10.1242/jeb.146.1.287.
The acoustic startle/escape response is a phylogenetically widespread behavioral act, provoked by an intense, unexpected sound. At least six orders of insects have evolved tympanate ears that serve acoustic behavior that ranges from sexual communication to predator detection. Insects that fly at night are vulnerable to predation by insectivorous bats that detect and locate their prey by using biosonar signals. Of the six orders of insects that possess tympanate hearing organs, four contain species that fly at night and, in these, hearing is sensitive to a range of ultrasonic frequencies found in the biosonar signals of bats. Laboratory and field studies have shown that these insects (including some orthopterans, lepidopterans, neuropterans and dictyopterans), when engaged in flight behavior, respond to ultrasound by suddenly altering their flight, showing acoustic startle or negative phonotaxis, which serve as bat-avoidance behavior. A neural analysis of ultrasound-mediated escape behavior was undertaken in the field cricket Telegryllus oceanicus. An identified thoracic interneuron, int-1, was shown to trigger the escape response, but only when the cell was driven (synaptically or electrically) at high spike rates, and only when the insect was performing flight behavior; avoidance steering only occurs in the appropriate behavioral context: flight. Thus, significant constraints operate upon the ability of int-1 to trigger the escape response. The integration of auditory input and flight central pattern generator output occurs in the brain. It is found that neural activity descending from the brain in response to stimulation by ultrasound is increased when the insect is flying compared to when it is not. Although the behavioral act of avoidance steering may appear to be a simple reflex act, further analysis shows it to be anything but simple.
听觉惊吓/逃避反应是一种在系统发育上广泛存在的行为，由强烈、意外的声音引发。至少有六个昆虫目进化出了鼓膜听器，用于从性交流到捕食者探测等听觉行为。夜间飞行的昆虫容易受到食虫蝙蝠的捕食，蝙蝠通过生物声纳信号探测和定位猎物。在拥有鼓膜听觉器官的六个昆虫目中，有四个目包含夜间飞行的物种，在这些物种中，听觉对蝙蝠生物声纳信号中发现的一系列超声波频率敏感。实验室和野外研究表明，这些昆虫（包括一些直翅目、鳞翅目、脉翅目和蜚蠊目）在进行飞行行为时，会通过突然改变飞行方向来对超声波做出反应，表现出听觉惊吓或负趋声性，这些行为起到了躲避蝙蝠的作用。对海洋长颚蟋进行了超声波介导的逃避行为的神经分析。一个已被识别的胸中间神经元，int-1，被证明能触发逃避反应，但只有当细胞以高脉冲频率被驱动（通过突触或电刺激）时，并且只有当昆虫正在进行飞行行为时才会触发；躲避转向只在适当的行为背景下发生：飞行。因此，int-1触发逃避反应的能力受到显著限制。听觉输入和飞行中央模式发生器输出的整合发生在大脑中。研究发现，与不飞行时相比，昆虫飞行时大脑对超声波刺激的下行神经活动会增加。尽管躲避转向的行为看起来可能是一种简单的反射行为，但进一步分析表明它绝非如此简单。
