An experimental investigation of a new ideal free distribution model

Abstract

We investigate a new continuous input ideal free distribution model which removes the assumption that resources are consumed as soon as they enter a patch. The model makes predictions about the standing crop of resources and allows consideration of the effects of simultaneous exploitation and interference competition. Using a group of cichlid fish competing for food items, we show that consistent with the model, standing crops can vary in continuous input situations. As predicted, higher standing crops are associated with increased intake rates. Furthermore, with greater numbers of competitors, standing crops are higher, suggesting that there is interference as well as exploitation competition in our system. An experiment to investigate the effects of fish density on the level of movement revealed that the reported interference competition could not be attributed to increased fish movement at higher density.