Abstract
Ideal free theory predicts how foraging animals that aim to maximise their food intake rate, will distribute themselves over food patches of different quality. The predicted distribution, however, strongly depends on the generalised functional response, i.e. the relationship between intake rate and both prey density and competitor density. The notion that competitors are not all alike but may differ in competitive ability complicates matters and implies that rather detailed knowledge is needed in order to arrive at reliable predictions of the spatial distribution of foraging animals. Yet, empirical studies have not kept pace with the jumps ideal free theory has made and at present experiments for the general case, where food availability can be characterised by the density of the standing crop in a patch, are extremely rare. The proposed project aims to study a single predator, the shore crab Carcinus meanas in detail to estimate the generalised functional response, taking into account differences in competitive ability among the predators. Subsequently, ideal free predictions on patch choice, which will be based on the most reliable generalised functional response model, will be experimentally tested.
Netherlands