Vibration sensitivity of leg scolopidial organs in Mantophasmatodea.

Autor(en)

Dirk Lang, Monika Eberhard, Harald Wolf

Abstrakt

In Mantophasmatodea, males and females communicate via substrate vibrations that are produced by

tapping the abdomen on the substrate surface. Males have a pronounced drumming organ on the subgenital

plate, while females tap in the absence of any specialised organ. Vibrational signals are species- and

gender-specific, and are of great importance for mate recognition and location. This communication system

shows several intriguing similarities to that of other animal groups using acoustic or vibrational

communication cues.

The mechanoreceptors responsible for the transduction and reception of the vibrational signals are as yet

unknown, but are probably scolopidial organs within the legs. We therefore investigated the responses of

the leg nerves to substrate vibrations applied to the tarsus, and we tried to identify responsive

mechanoreceptors by ablation experiments. Males and females of the species Karoophasma biedouwense

and a yet undescribed, sympatric species which belongs to the same family (Austrophasmatidae) were used

in this study. Intensity and frequency characteristics were determined, and compared to the intensity and

frequency ranges of the communication signals.

Best frequencies were between 40 and 640 Hz; the total frequency range where responses were recorded in

the leg nerve was between 5 Hz and 2560 Hz. These values agree well with the frequencies observed in the

communication signals. Threshold intensities at the best frequencies were close to 0,005 m/s2, or 0,5 nm

displacement (peak-to-peak values) at 640 Hz. The responses of the leg nerves of different legs (fore-,

mid-, and hindlegs) did not differ much.

Ablation experiments indicate that both, subgenual organ and femoral chordotonal organ respond to

vibration stimuli, whereas the tarso-praetarsal chordotonal organ is not involved in vibration reception.

Organisation(en)

Externe Organisation(en)

University of Cape Town, Universität Ulm

Seiten

877-877

Anzahl der Seiten

Publikationsdatum

2009

ÖFOS 2012

106025 Neurobiologie, 106046 Tieranatomie

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