Life history evolution in a community context

Life histories are predicted to evolve when the age schedules of mortality shift due to top-down forces such as predation. Theory on how competitive interactions alter the life history is rare. We use an explicit consumer-resource model to show that changes in the way organisms interact with their resources and changes in the properties of those resources can alter the optimal life history of a consumer. When older/larger organisms are better competitors, delayed maturity can be favored. When older/larger individuals are better competitors but also shift their resource use with age or size, alternative life histories are possible. We further show that when two species compete for shared resources, selection tends to make the life histories of the two competitors more similar. These results, some of which are opposite to predictions from traditional theory, illustrate the importance of incorporating explicit interactions between trophic levels into models for life history evolution.