| Abstract: | Functional response curves were constructed for adult Ranatra dispar feeding on four different densities of notonectid prey at 15, 20, 25 and 30°C. Values for the attack-rate and handling time were estimated from Roger's random predator equation. The most generally applicable response was the type II, with the mean number of prey eaten increasing with increase in temperature. The attack-rate was linearly related to temperature while handling time decreased exponentially with increase in temperature, although values changed very little between 20 and 30°C. It is suggested that changes in metabolic activity and related ‘hunger’ effects on various components of predatory behaviour account for the observed number of prey eaten up to 25°C, however, an increase in the level of prey activity at 30°C may influence the observed number of prey caught (and eaten) at this higher temperature. |
