Learning behavior and changes in the levels of RNA during learning in grasshopper, Poecilocera picta

Abstract

Grasshoppers, Poecilocera picta , were trained to change leg position to avoid an electric shock using a procedure originally developed by Horridge, 1962a , Horridge, 1962b . Experiments were conducted on male and female grass hoppers at 8 AM, 12 Noon, 4 PM and 8 PM. Observations on the learning pattern revealed a noticeable diurnal variation in the learning behavior of males whereas females did not show marked variation. The learning performance of males was best at 8 AM. Females showed a tendency to learn faster at both 8 AM and 4 PM. The results suggest that males learn at a faster rate and retain the learned behavior longer than females. Changes were noticed in the relative concentrations of RNA in the metathoracic ganglia of the experimental and control insects after the training process. The present shock avoidance procedure appears to lead to short term information storage in the ganglionic aggregates of the grasshopper nervous system.