A dynamic game-theoretic model of parental care

We present a model in which members of a mated pair decide whether to care for their offspring or desert them. There is a breeding season of finite le ngth during which it is possible to produce and raise several batches of of fspring. On deserting its offspring, an individual can search for a new mat e. The probability of finding a mate depends on the number of individuals o f each sex that are searching, which in turn depends upon the previous care and desertion decisions of all population members. We find the evolutionar ily stable pattern of care over the breeding season. The feedback between b ehaviour and mating opportunity can result in a pattern of stable oscillati ons between different forms of care over the breeding season. Oscillations can also arise because the best thing for an individual to do at a particul ar time in the season depends on future behaviour of all population members . In the baseline model, a pair splits up after a breeding attempt, even if they both care for the offspring. In a version of the model in which a pai r stays together if they both care, the feedback between behaviour and mati ng opportunity can lead to more than one evolutionarily stable form of care . (C) 2000 Academic Press.