Abstract
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.