Nymphal development of the auditory system in the praying mantisHierodula membranacea Burmeister (Dictyoptera, Mantidae)

Abstract

Like other praying mantises, Hierodula membranacea has a single midline ear on the ventral surface of the metathorax. The ear comprises a deep groove with two tympana forming the walls. A tympanal organ on each side contains 30-40 scolopophorous sensillae with axons that terminate in the metathoracic ganglion in neuropil that does not match the auditory neuropil of other insects. Nymphal development of the mantis ear proceeds in three major stages: 1) The tympanal organ is completely formed with a full complement of sensillae before hatching; 2) the infolding 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 move to become tightly apposed to the inner surfaces of the tympana. Auditory sensitivity gradually increases beginning with the fifth instar and closely parallels tympanum and tracheal sac growth. Late instar nymphs have auditory thresholds of 70-80 dB sound pressure level (SPL). Appropriate connections of afferents to a functional interneuronal system are clearly present by the eighth instar and possibly much earlier. The pattern of auditory system ontogeny in the mantis is similar to that in locusts and in noctuid moths, but it differs from crickets. In 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 thought to be primitively deaf.

The phylogenetic system of Mantodea (Insecta: Dictyoptera)

“…Its morphology has been described in detail by Yager & Hoy (1987), and its physiology was carefully studied by Yager & Hoy in 1989. The postembryonic development of the hearing organ from both physiological and morphological angles were described by Yager (1996b), and the homologous structures in cockroaches were identified and discussed by Yager (2005). In 1990, Yager found evidence for distinct sexual dimorphism of the auditory system, being closely correlated with wing length dimorphism and capability of flight.…”

“…prey location or intraspecific communication), that were lost when the ear took over its function as a bat-detecting device (Yager & Svenson 2008: 561). These hypotheses gain support by the fact that mantodean nymphs already acquire the hearing ability during the second half of their nymphal development, not only as adults (Yager 1996b(Yager , 1999b.…”

“…Among them are Przibram & Megušar (1912), Adair (1914), Sztern (1914), Bugnion (1921a), Przibram (1930), Przibram & Brecher (1930), Roberts (1937a, b), Terra (1980), Nickle (1987), Köchy (1991), Yager (1996b), and Karuppanan (1998). Beier (1964a: 855 ff.…”

Serially homologous ears perform frequency range fractionation in the praying mantis, Creobroter (Mantodea, Hymenopodidae)

“…The serial homology is reinforced by the observation that the metathoracic ear near the midpoint of its nymphal development is virtually indistinguishable from the adult mesothoracic ear (Yager 1995). The cuticular elements of the auditory systems in the two segments are also innervated by the same branch of the same nerve root (Nerve 7), and the central terminations of the afferents are very similar (D.D.…”

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“…This is correlated to the formation of the tympanal trachea and the thinning of the cuticle resulting in the adult tympanum [22,25]. A similar development occurs in the Mantodea [26]. In both groups of hemimetabolous insects the larvae are rather similar to the adult.…”