Underlying mechanisms and evolutionary consequences of individual specialization

Abstract

Within-population niche variation can be attributed to individual specialization (IE), a type of ecological variation characterized by the presence of individuals whose niches are subsets of the population niche. Mechanisms underlying IE include functional trade-offs associated with morphology, physiology, and behavior as well as extrinsic factors such as intra- and interspecific competition, predation, and ecological opportunity. Additionally, the scarce available empirical evidence indicates that traits of animal personality can generate individual niche variation. An important implication of IE is that, when it is present, competitive interactions become frequency dependent, a necessary condition for the occurence of disruptive selection in a series of models of quantitative genetics and niche evolution. However, the relationship between IE and disruptive selection has never been empirically demonstrated. The objectives of the present proposal are: (1) to investigate the role of animal personality in the occurrence of IE, (2) to investigate the effects of micro-spatial variation in ecological opportunity on the degree of IE, (3) to investigate the role of morphology as a proximate cause of IE and (4) to investigate the relationship between the degree of IE and gradients of quadratic natural selection in natural populations. We will study frog species of the Atlantic Forest and the Pantanal in which high degrees of IE have already been documented, making them excellent models to advance the study of the mechanisms and implications of this phenomenon. (AU)