Mathematical modelling for intra-specific brood-parasitism: coexistence between parasite and non-parasite

In this paper, we consider an aspect of the intra-specific brood-parasitism with a mathematical modelling. As in case of moorhen Gallinula chloropus, the case dealt with in this paper in such that just a part of:the whole pop ulation has the parasitising behaviour against the individuals belonging to another part of non-parasite subpopulation that does not have such behavio ur. Analysing the expected fitness gain from the brood-parasitism, we consi der the condition in order that parasite individuals coexist with nonparasi te ones within a population. From the mathematical modelling analysis, it i s shown that the stable equilibrium frequency of parasite individuals withi n a population, if exists, depends on the difference among individuals in t erms of the individual quality reflected to the survival probability of bre d offsprings. (C) 1999 Elsevier Science Inc. All rights reserved.