Dd. Yager, NYMPHAL DEVELOPMENT OF THE AUDITORY-SYSTEM IN THE PRAYING-MANTIS HIERODULA-MEMBRANACEA BURMEISTER (DICTYOPTERA, MANTIDAE), Journal of comparative neurology, 364(2), 1996, pp. 199-210
Like other praying mantises, Hierodula membranacea has a single midlin
e ear on the ventral surface of the metathorax. The ear comprises a de
ep groove with two tympana forming the walls. A tympanal organ on each
side contains 30-40 scolopophorous sensillae with axons that terminat
e in the metathoracic ganglion in neuropil that does not match the aud
itory neuropil of other insects. Nymphal development of the mantis ear
proceeds in three major stages: 1) The tympanal organ is completely f
ormed with a full complement of sensillae before hatching; 2) the info
lding and rotations that form the deep groove are completed primarily
over the first half of nymphal development; and 3) over the last five
instars (of ten), the tympana thicken and broaden to their adult size
and shape, and the impedance-matching tracheal sacs also enlarge and m
ove to become tightly apposed to the inner surfaces of the tympana. Au
ditory sensitivity gradually increases beginning with the fifth instar
and closely parallels tympanum and tracheal sac growth. Late instar n
ymphs have auditory thresholds of 70-80 dB sound pressure level (SPL).
Appropriate connections of afferents to a functional interneuronal sy
stem are clearly present by the eighth instar and possibly much earlie
r. The pattern of auditory system ontogeny in the mantis is similar to
that in locusts and in noctuid moths, but it differs from crickets. I
n evolutionary terms, it is significant that the metathoracic anatomy
of newly hatched mantis nymphs matches very closely the anatomy of the
homologous regions in adult cockroaches, which are closely related to
mantises but are without tympanal hearing, and in mantises that are t
hought to be primitively deaf. (C) 1996 Wiley-Liss, Inc.