Experimental studies on acarine predator–prey interactions: effects of predator age and feeding history on prey consumption and the functional response (Acarina: Phytoseiidae)

Abstract

Laboratory experiments were performed to determine the functional response to prey density of various instars of two species of predacious phytoseiid mites, Phytoseiulus persimilis and Amblyseius degenerans, and to examine the effects of predator age and nutritional history on their responses. The experiments showed that the nutritional requirements of the predators, the time that they are exposed to prey in relation to their life-span, increasing age, and differences in nutritional history, can have important effects on predatory behaviour and the functional response. Prolonged exposure to one density of prey can cause lags in predation rates when the prey density is changed. The results indicated that functional responses are probably multiform in certain predators and the above factors may provide an explanation of the variety of responses previously reported for species of phytoseiid mites. Phytoseiulus persimilis appeared to be more sensitive to some of these factors than A. degenerans and was shown to be different in many aspects of its predatory behaviour.