Effect on predatory performance of the presence of prey after moulting in the water stick insect, Ranatra linearis

ABSTRACT. During the first 4h following moulting, Ranatra linearis L. (Heteroptera, Nepidae) perform numerous claw and femur foreleg movements, but do not then catch any prey (e.g. Daphnia ). The frequency of these movements depends on the presence of potential prey, and is significantly higher in the presence of potential prey items than in their absence. The presence or absence of prey during these four post-moult hours influenced subsequent performance. Ranatra moulting in the absence of prey showed later a lower catching success and a smaller proportion of complex predatory movements at all stages of development than did Ranatra moulting in the presence of prey, all other factors being similar. The importance of this deficit resulting from depriving Ranatra of the presence of prey during the post-moult period is discussed.