Johannes Strauß, Reinhard Lakes-Harlan (2009): The evolutionary origin of
auditory receptors in Tettigonioidea: the complex tibial organ of
Schizodactylidae. Naturwissenschaften 96(1), 143-146.
Abstract: Audition in insects is of polyphyletic origin. Tympanal ears
derived from proprioceptive or vibratory receptor organs, but many questions
of the evolution of insect auditory systems are still open. Despite the
rather typical bauplan of the insect body, e.g., with a fixed number of
segments, tympanal ears evolved at very different places, but only
ensiferans have ears at the foreleg tibia, located in the tibial organ. The
homology and monophyly of ensiferan ears is controversial, and no precursor
organ was unambiguously identified for auditory receptors. The latter can
only be identified by comparative study of recent atympanate taxa. These
atympanate taxa are poorly investigated. In this paper, we report the
neuroanatomy of the tibial organ of Comicus calcaris (Irish 1986), an
atympanate Schizodactylid (splay-footed cricket). This representative of a
Gondwana relict group has a tripartite sensory organ, homologous to
tettigoniid ears. A comparison with morphology-based cladistic phylogeny
indicates that the tripartite neuronal organization present in the majority
of Tettigonioidea presumably preceded evolution of a hearing sense in the
Tettigonioidea. Furthermore, the absence of a tripartite organ in Grylloidea
argues against a monophyletic origin and homology of the cricket and katydid
ears. The tracheal attachment of sensory neurons typical for ears of
Tettigonioidea is present in C. calcaris and may have facilitated cooption
for auditory function. The functional auditory organ was presumably formed
in evolution by successive non-neural modifications of trachea and tympana.
This first investigation of the neuroanatomy of Schizodactylidae suggests a
non-auditory chordotonal organ as the precursor for auditory receptors of
related tympanate taxa and adds evidence for the phylogenetic position of
the group.
URL: http://www.springerlink.com/content/978v07m50r5hw636/
For reprints please contact Reinhard Lakes-Harlan (Email:
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