Philopatry, Inbreeding, and the Evolution of Sex

Book excerpt: In this comprehensive synthesis, William M. Shields introduces a provocative new hypothesis linking the previously disconnected topics of philopatry, inbreeding, and sex. Shields draws widely from theory and data in genetics, ecology, and behavior in exploring the evolutionary causes and consequences of philopatric (localized) and vagrant dispersal, inbreeding and outbreeding mating systems, and asexual and sexual reproduction. His resulting hypothesis, that philopatry evolved because it increases inbreeding intensity and that inbreeding has survival value, has profound implications for the future study of evolutionary theory.