Neuroethology of audition and bat evasion in praying mantises

Abstract

Many praying mantises have a unique auditory system comprising a single ear located in the ventral midline of the thorax. The hearing is nondirectional, and best frequencies range from 25 kHz to over 100 kHz depending on the species. Bat-like ultrasound triggers complex evasive maneuvers in flying mantises that requires CNS processing in the head. A mirror-image pair of interneurons (501) rapidly (<20 ms ) carries auditory information from the auditory nerve to the brain and these neurons are the best candidates as the primary input to the evasive response. The 501 recordings from an electrode chronically implanted in a mantis while it is being attacked by a flying, echolocating bat show that 501 responds strongly to bat cries and faithfully reports the temporal pattern of the echolocation cries during the early stages of the attack. However, during the last 200–250 ms before capture (beginning in mid-Buzz I), 501 falls silent. Although consistent with several physiological characteristics of 501, the result is surprising behaviorally. However, based on behavioral latencies, the latest that a successful response could be triggered is 200–250 ms before capture, and silencing 501 after that may prevent potentially dangerous habituation of the interneuron.