Life-history traits as predictors of expected genetic contributions 15 years later in a cooperatively breeding bird

ABSTRACT An individual’s life history plays an important role in how successful individuals are in passing on their genes to future generations. However, exactly which life-history traits best approximate an individual’s long-term genetic contributions remains poorly studied, especially in cooperative breeders. Here, we use a genetic pedigree and long-term data of the closed population of the Seychelles warbler (Acrocephalus sechellensis) to calculate the expected individual genetic contributions (IGC) after 15 years (or ∼3 generations) across 11 cohorts. Using a Bayesian analysis we then quantified and compared how well six important life-history traits predict IGC in each sex of this cooperatively breeding species. The life-history traits compared were: acquisition of a dominant breeding position, age at first breeding attempt, tenure as a dominant breeder, lifespan, and LRS (measured as both the number of independent [surviving 3 months+] and recruited [surviving 1 year+] offspring produced over an individual’s lifetime). An individual’s lifetime reproductive success (LRS) was the strongest predictor of IGC and this predictive power did not differ across the different measurements used. However, this predictive power did differ between sexes, explaining ∼61-62% of IGC variation in males versus ∼47-49% in females owing to the larger variation among males in their annual reproductive success. Across other life-history traits the predictive power of IGC was similar across both sexes but differed between life-history traits considerably (2-37%). Comparing these predictive powers suggested that lifespan and the duration of a dominant breeding position are far more important in shaping long-term genetic contributions than if and when in their life they acquired dominance. Overall, these findings give insight into the individual and population-level processes influencing future gene pools and illustrate how life-history evolution is shaped by sex-specific reproductive patterns and cooperative breeding dynamics. Competing Interest Statement The authors have declared no competing interest.