Siblicide, family conflict and the evolutionary limits of selfishness

In animal and plant taxa where parents deposit an oversupply of eggs/neonates into a spatially restricted 'nursery', intense sibling competition commonly results. An inversion of Hamilton's rule identifies the theoretical lower limit for how an individual in a sexual species ought to favour its own welfare over that of its close kin in such an ecological squeeze. A broad array of behavioural and life-history phenotypes appears to have evolved, at least in part, for dealing with close kin as serious competitors. We have recently summarized the theory and empirical data addressing both sibling competition and parent-offspring conflict (Mock & Parker 1997, The Evolution of Sibling Rivalry), and here present a précis that aims both to give a quick overview of that fuller treatment while allowing us to update the book's literature review with a few late-breaking findings. Copyright 1998 The Association for the Study of Animal Behaviour