Adaptive Dynamics, Resource Conversion Efficiency, and Species Diversity

Abstract

Previous work on the theory of continuous evolutionary games and adaptive dynamics has shown that a species can evolve to an evolutionarily stable minimum on a frequency-dependent adaptive landscape (e.g., Brown and Pavlovic [7], andAbrams etal. [3], [4]). While such stable minima are convergent stable, they can be invaded by rare alternative strategies. The significance of such stable minima for biology is that they produce “disruptive selection” which can potentially lead to speciation (Metz et al. [20], Geritz et al. [16], Cohen et al. [11], and Mitchell [21]. Previous analyses of Lotka-Volterra competition communities indicate that stable minima and speciation events are more likely to occur when the underlying resource distribution is broader than the resource utilization functions of the competing species. Here, I present an analysis based on a resource-consumer model which allows individuals to adaptively vary resource use as a function of competitor density and strategy. I show that habitat specialization, stable minima, community invasibility, and sympatric speciation are more likely when individuals are more efficient at converting resources into viable offspring. Conversely, factors that inhibit conversion efficiency inhibit speciation and promote competitive exclusion. This model suggests possible links between species diversity and factors influencing the resource conversion efficiency, such as climate, habitat fragmentation, and environmental toxins.