Ontogenetic asymmetry in ecology: its origins and its implications for population and community dynamics

Abstract:  In this talk I will show that the combination of two ubiquitous biological mechanisms, demographic differences between juvenile and adult individuals and the energy requirements to keep a living body alive (somatic maintenance costs), is sufficient to overturn a large number of ecological rules-of-thumb derived from the unstructured population models that form the basis of current ecological theory. As one example, classic theory predicts that when two species compete for a shared resource and are exposed to a shared predator, the inferior competitor will go extinct if it is also more sensitive to predation. In contrast, if basic maintenance costs are accounted for and the juvenile maturation rate of the inferior competitor is more resource-limited than its reproduction rate, an inferior competitor that is also more sensitive to predation will drive its opponent to extinction in the presence of the shared predator, despite its double handicap.