A game theoretical approach to conspecific brood parasitism

We constructed a game theoretical model to predict optimal patternsof egg laying in systems where individuals lay in the nestsof others as well as in their own nests. We show that decreasingthe effect of position within an egg-laying sequence on theworth of an egg should lead to reduced parasitism. Indeed,parasitism can only flourish if the worth of an egg to its biologicalparent declines with the total number of eggs laid in that nest.Further, we found that increasing the intrinsic costs of eggproduction should lead to an increased propensity for conspecificbrood parasitism. The model also predicts that variation inhosts' ability to reject parasitic eggs has little effect onparasitism until this ability is well developed.