The influence of eating and rejecting prey items upon feeding and food searching behaviour in Gasterosteus aculeatus L

Variation in encounter outcome and in area restriction and area avoidance subsequent to eat and reject encounters respectively was examined in relation to immediately prior behaviour and to the total previous experiential history within the daily feeding session. Neither outcome nor post-encounter behaviour was found to be totally dependent upon the current encounter. The motivational variables involved, however, could not be attributed simply to an increase in ‘satiation’ with cumulative intake over the session. It is proposed that, in addition, short-term positive and negative motivational after-effects are present after eat and reject encounters respectively. The former positively influencing the probability that a subsequent prey item will be eaten and the latter negatively influencing that probability. A rough approximation of the duration of these motivational after-effects was made.