Evolution of Life History Strategies under Consumer Resource Interactions

Nature is a full of diverse life history strategies (demographic diversity); however, our understanding of how it is determined under consumer resource interactions is still limited. I compared a food web model with stage-structured populations (structured model) with an equivalent model with unstructured populations (unstructured model). Both models included the maximum of 15 populations, incorporated energetic processes, and allowed existing populations to go extinct and new populations to invade over time. When the structured model reached stability, three distinct life history strategies emerged, corresponding to equilibrium, opportunistic, and periodic life history strategies. Although results from the two models shared some similarities, there were clear differences between them. For example, reducing niche width led to an increased number of populations under the unstructured model, but led to a reduced number of populations under the structured model. The average trophic level of consumers in the structured model was almost always higher than that in the unstructured model. These results compel the need for a re-evaluation of current understanding in community dynamics, developed mostly without considering population stage structures. The results also suggest the potential importance of consumer resource interactions for shaping life history strategies of organisms.