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Gating of locomotor activity in the cave‐cricket, Troglophilus cavicola
Author(s) -
KASTBERGER GERALD
Publication year - 1984
Publication title -
physiological entomology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.693
H-Index - 57
eISSN - 1365-3032
pISSN - 0307-6962
DOI - 10.1111/j.1365-3032.1984.tb00712.x
Subject(s) - cricket , biology , jumping , grasshopper , gating , orthoptera , anatomy , acheta , cave , zoology , ecology , biophysics , physiology
. Cave‐crickets of the genus Troglophilus exhibit a slope dependent gating of locomotor behaviour (Kastberger, 1982), which is mainly expressed by a suppression of evasive jumping on inclined surfaces. A similar dependence of the jumpting rate on the ground inclination to that seen in the cave‐cricket can be shown in the African cricket Phaeophyllacris and in the grasshopper Chorthippus. They differ only in the basic motivation for jumping. In this study, free‐moving and tethered cave‐crickets were studied to elucidate the inclination‐sensitive control of gating locomotor activity. Cave‐crickets with cauterized tarsal nerves exhibit only a 20% reduction in jumpting rate at slopes up to 45d̀ compared with intact crickets. Freely moving crickets with compensated body weights show a suppression of evasive jumping which is complete if the vertical force overrides the body weight. Dorsally tethered cave‐crickets which contact a rotary globe with their tarsi, show a significant increase in the latency of jerking beyond 60d̀ inclination. Crickets placed on a floating boat and partially fixed respond to both static and dynamic forces applied to the longitudinal axis of the cricket. Static towing forces induce passive movements and the rate of active balancing are linearly correlated to the force applied. Under dynamic forces the rate of balancing is dependent on the longitudinal position of the legs and on the direction of force. This basic relation is changed by additional stimulation such as light and vibration. Locomotor activity is gated in a different mode, if the light interval is placed during forward or during backward forcing. Light‐off suppresses locomotor activity. The results of dynamic forcing suggest the existence of a gain control which might be responsible for modal and temporal effects in gating locomotion.