Behavioral and Evolutionary Neurobiology: A Pluralistic Approach

Abstract

SYNOPSIS. An individual's existing phenotype is defined by behavioral and structural characters in the context of an ecological environment which is inclusive of both biotic and abiotic factors. Multiple explanations, designated here as mechanisms,life history, fitness, and evolutionary history, can account for the existence of phenotypic characters and their relationships to each other. These explanations can be described pictorially using a Venn—like diagram with three overlapping circles; each circle represents the potential range of variation for each character or the environment. The center of the diagram, a point of overlap in all three circles, is the existing phenotype. Mechanistic explanations establish linkages either between characters or between characters and the environment; they are represented spatially by the overlap between two circles identified here as behavioralecological, behavioral—structural, and ecological—structural mechanisms. Life history explanations incorporate the temporal dimension of an individual's age so that sequences of Venn diagrams would symbolize an individual's entire life history. Fitness explanations identify the relationship of a character, mechanism, life history stage or entire life history strategy to reproductive success and survival. Lastly, explanations based on evolutionary history account for the current phenotype in terms of interactions between characters and ecological environments along the temporal dimension of geological time. Together, multiple explanations contribute to a pluralistic understanding of an existing phenotype, as used in this essay to explain vocalization behaviors exhibited by alternative male reproductive morphs in a teleost fish, the plainfin midshipman, Porichthys notatus .