Limited Prédation Capacity by Generalist Arthropod Predators on the Cereal Aphid,Rhopalosiphum padi

Abstract

Predatory species that are considered beneficial in the limitation of cereal aphids might be expected to display a high preference for aphids. Experiments with several potential generalist aphid predators have revealed a low preference for the aphid Rhopalosiphum padi and a low tolerance limit to the consumption of aphids. In these experiments, the limited tolerance of some carabid beetles and linyphiid spiders to Rhopalosiphum padi is demonstrated. Twenty four h food consumption (mg dw mg⁻¹) of two prey types, R padi and Drosophila melanogaster, was determined in both satiated and starved predator individuals. In most cases the feeding capacity for aphids was found to be consistently lower than for fruit flies. Aspects of the natural control of a pest that is of low preference and is not well tolerated by its predators are discussed.