David D. Yager
Dept. of Psychol., Univ. of Maryland, College Park, MD 20742
Many praying mantises have a well-developed auditory sense mediated by a single, midline ear that hears only ultrasound. Hearing appears gradually in praying mantis nymphs. The neural elements of the peripheral auditory system are in place at hatching. The tympanum is represented only by a small slit and the ear components face posteriorly. The adult medial orientation is achieved by progressive rotation of the walls and broadening of the slit into a membrane. Increasing auditory sensitivity corresponds to the progressive development of impedance-matching tympanal air sacs. There are four major patterns of auditory structure and function among the 2000 mantis species. (1) Most mantises have a single ear and good ultrasonic hearing. (2) In a third of the species males have a functional ear, but females do not. (3) Mantises of one subfamily have not one, but two ears. The ears are serial homologs that hear in entirely different frequency ranges. (4) A few groups of mantises are deaf and have ``ears'' almost identical to those of newly hatched nymphs. Based on these results, it is possible to suggest an ``auditory phylogeny'' for the suborder Mantodea.