PHYSIOLOGY OF ATYMPANATE TIBIAL ORGANS IN FORELEGS AND MIDLEGS OF THECAVE-LIVING ENSIFERA, TROGLOPHILUS-NEGLECTUS (RAPHIDOPHORIDAE, GRYLLACRIDOIDEA)

The complex tibial organs of the Ensiferan species Troglophilus neglec tus (Raphidophoridae, Gryllacridoidea) do not differ significantly in their morphology in all six legs. They consist of a normal developed s ubgenual organ and an intermediate organ (when compared with the condi tions in tettigoniids). Physiologically, the receptor cells of the com plex tibial organs of the fore- and midlegs could be grouped into 11 f unctional types. Four of these types belong probably to the intermedia te organ; the cells of these types respond to frequencies from 700 Hz to 2,000 Hz to both substrate- and airborne sound but are more sensiti ve to the former. The remaining seven types belong to the subgenual or gan. Their receptors are tuned to stimuli within frequencies ranging f rom 200 Hz to 700 Hz. The classification into different functional typ es and their attribution to the two receptor organs were derived from a comparison with the physiological properties of the receptors of the complex tibial organs in the midlegs of tettigoniids. In the Trogloph ilinae the subgenual and intermediate organs are structurally very sim ilar to those of the midleg receptor organs of tettigoniids; only the most distal part of the intermediate organ and the crista acoustica is missing. Consistent with the similarities in the proximal part of the receptor complex, the receptor cells of the subgenual and intermediat e organs show similar physiological characteristics. (C) 1995 Wiley-Li ss, Inc.