The evolutionary significance of latent reproductive rate in a long-lived vertebrate

In Focus: Chambert, T., Rotella, J. J. & Garrott, R. A. (2014) An evolutionary perspective on reproductive individual heterogeneity in a marine vertebrate. Journal of Animal Ecology, 83, 1158-1168. Chambert, Rotella & Garrott (2014) used long-term data to assess the evolutionary significance of individual latent reproductive rate in female Weddell seals. Latent reproductive rates capture the differences among individuals in terms of their propensity to breed; they are conceptual and mathematical constructs. Neither recruitment probability nor age of first breeding of daughters was related to the mother's latent reproductive rate, but there was evidence of a weak positive relationship between the latent reproductive rates of mothers and daughters, suggesting some degree of heritability in this trait. Females with a high latent reproductive rate were expected to produce 2.0 times as many recruited females and 2.1 times as many grandchildren as females with a low reproductive rate. There was substantial stochastic variation in the number of offspring and grandchildren produced, but the inter-individual variability in female latent reproductive rate may have important fitness consequences.