DYNAMICS OF LEARNING IN THE PRAYING MANTIS (STAGMATOPTERA-BIOCELLATA)

Abstracto(1)A praying mantis faced with a bird displays a 'frightening reaction' called a deimatic reaction, habituation of this response is the learning process under study.(2)Speed of learning and retention when the same number of training sessions are given, seem to depend only on the total number of trials per session.(3)Anoxia with nitrogen during training, impairs retention on the following day, but this amnesic effect diminishes with training. After 8 days of training, memory proves to be insensitive to a N2-shock.(4)Mantis that receive two sessions of discontinuous training (30 trials/day each of 2 min duration with 10 min between trials) show long retention (at least 6 days) but this long memory is dramatically disrupted by N2-anoxia.(5)Results seem not to fit basic assumptions of the dualistic theory of memory, i.e. the STM-LTM dichotomy. It is suggested that the learning process involves two mechanisms with different physiological bases but which nevertheless act together during several training sessions. One mechanism would underlie memories that are sensitive to anoxia (S memory) and the other, memories that are insensitive (I memory). The relative participation of these mechanisms could change during training, in such a way that the greater the degree of training, the smaller the contribution by the S process and the greater that of I process.(6)When mantis are trained with successive sessions each consisting of a single long trial of 2 hr per day (continuous training), they learn more slowly than when trained with the usual discontinuous method. With continuous training 10 sessions yield a level of habituation similar to that reached after 8 days of discontinuous training. However, after 10 days of continuous training, memory is still sensitive to impairment by anoxia. The possible meaning of this difference is discussed. © 1979 Pergamon Press Ltd.