Similar structural dimensions in bushcricket auditory organs in spite of different foreleg size: consequences for auditory tuning.
The bushcricket species Decticus albifrons, Decticus verrucivorus and Pholidoptera griseoaptera (Tettigoniidae) belong to the same subfamily (Decticinae) but differ significantly in body size. In spite of the great differences in the dimensions of the forelegs, where the auditory organs are located, the most sensitive range of the hearing threshold lies between 6 and 25 kHz in each case. Only in the frequency range from 2 to 5 kHz and above 25 kHz, significant differences are present. The anatomy of the auditory receptor organs was compared quantitatively, using the techniques of semi-thin sectioning and computer-guided morphometry. The overall number of scolopidia and the length of the crista acustica differs in the three species, but the relative distribution of scolopidia along the crista acustica is very similar. Additionally, the scolopidia and their attachment structures (tectorial membrane, dorsal tracheal wall, cap cells) are of equal size at equivalent relative positions along the crista acustica. The results indicate that the constant relations and dimensions of corresponding structures within the cristae acusticae of the three species are responsible for the similarities in the tuning of the auditory thresholds.
Rössler
W
W
Fachbereich Biologie-Zoologie, Philipps-Universität Marburg, FRG.
Kalmring
K
K
D000161:Acoustic Stimulation; D000818:Animals; D001309:Auditory Threshold / Q000502:physiology*; D003198:Computer Simulation; D004594:Electrophysiology; D005121:Extremities / Q000033:anatomy & histology*; D005260:Female; D006135:Gryllidae / Q000033:anatomy & histology* / Q000502:physiology; D008297:Male; D012679:Sense Organs / Q000033:anatomy & histology* / Q000502:physiology; D013045:Species Specificity; D000159:Vestibulocochlear Nerve / Q000502:physiology