Optimal Diet Selection with Variable Nutrient Intake: Balancing Reproduction with Risk of Starvation

We develop a model to predict optimal diet selection when energy intake varies over consecutive foraging periods. The model assumes that fitness is maximized when the forager maximizes its net reproduction (survivorship x reproduction) over some specified time period. This goal differs from earlier risk-sensitive foraging models which assume that the forager minimizes the risk of failing to satisfy minimum requirements for survivorship or reproduction. In our model, the net number of offspring produced per reproductive bout is expressed as an explicit function of fitness gained from reproduction and fitness lost due to starvation risk for different potential diets. Potential model solutions are explored graphically and are compared with solutions for previous foraging models. In general, the model predicts that foragers with a goal of maximizing net reproduction should accept greater risks of starvation than foragers with a goal of minimizing the risk of failing to satisfy minimum energy requirements.