AGE-SPECIFIC REPRODUCTIVE SUCCESS: EVIDENCE FOR THE SELECTION HYPOTHESIS

Abstract

Age-specific reproductive success has been demonstrated in many species. Three hypotheses have been raised to explain this general phenomenon: the experience hypothesis based on age-specific reproductive experience, the effort hypothesis based on age-specific reproductive effort, and the selection hypothesis based on progressive disappearance of phenotypes due to variation in individual productivity and survival. We used data from a long-term study of Leach's storm-petrels (Oceanodroma leucorhoa) to present a single test of mutually exclusive predictions about the relationship between early breeding success and longevity. There should be no correlation between early breeding success and longevity under the experience hypothesis, a negative correlation under the effort hypothesis, and a positive correlation under the selection hypothesis. We found a significant (P < 0.0001) positive relationship between success in the first two breeding attempts and longevity in this population of long-lived seabirds, strongly suggesting that low-productivity parents were also less likely to survive early breeding. These data provide some of the strongest support to date for the selection hypothesis.