Lessons from a limpet: modelling decisions of central place foragers

Central place foraging behaviour is widespread among both vertebrates and invertebrates. Due to their limited behavioural repertoires, homing limpets (Mollusca Gastropoda) represent an ideal system for the study of optimisation problems in central place foragers. A simple model of limpet behaviour is proposed, based on stochastic dynamic programming, and predictions are compared with published observations. The model was kept as general as possible, so as to be flexible enough to describe the behaviour of almost any central place forager. The state of the forager was characterised by two state variables: the quality of food encountered and the distance from the home site. At each time step, the animal must decide if it is: (a) to accept a patch it has encountered, (b) to continue onwards or (c) to return homewards. Average patch energy content was assumed to increase with distance from home. To simulate different spatial arrangements of resources, the possibility of an autocorrelation in rewards, due to s...