Defense posture and leg-position learning in a primitive insect utilize catchlike tension.
The capability for conditioning of leg position, using loud sound as an aversive natural reinforcement, was examined in a primitive New Zealand insect, the weta (Orthoptera: Stenopelmatidae). Electromyographic recordings were made during the conditioning. A majority of wetas tested came to occupy stably a metathoracic tibial position window, coupled to turning off the sound, set in either flexion or extension away from the preferred rest position. Steady tensions of up to 7 g in extension and 5 g in flexion were produced. However, no electromyographic activity accompanied the tension. It is concluded that the insects are using a peripheral catchlike mechanism to adjust posture.
D000818:Animals; D002375:Catalepsy / Q000503:physiopathology; D003214:Conditioning, Classical / Q000502:physiology*; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D009043:Motor Activity / Q000502:physiology; D009132:Muscles / Q000502:physiology*; D009469:Neuromuscular Junction / Q000502:physiology; D009987:Orthoptera / Q000502:physiology*; D011187:Posture; D013045:Species Specificity; D009435:Synaptic Transmission