Life-history strategies covary with a suite of behavioral and physiological responses along a slow-fast continuum, known as pace-of-life-syndrome. Particularly in long-lived species, pace-of-life is expected to influence breeding strategies, making it a potentially important factor in mate choice. It has been proposed that telomere length (TL) may integrate individual physiological components and survival prospects that underlie individual differences in pace-of-life. In the brown booby (Sula leucogaster), a long-lived seabird, we investigated whether TL may indicate individual pace-of-life by examining how it relates to mitochondrial DNA copy number (mtDNAcn), corticosterone (cort) levels, and skin coloration—a condition-dependent sexual trait. Then, we tested whether there is assortative mating by TL, and whether the degree of TL similarity between partners influences an individual’s likelihood of changing mates and physiological state (mtDNAcn and cort levels). Because environmental conditions may have important effects on the individual pace-of-life, the study was performed in two colonies with contrasting breeding conditions. We found that TL was positively related to mtDNAcn (but not cort levels), suggesting that individuals with shorter telomeres have reduced mitochondrial activity and aerobic capacity. TL was reflected in sexual coloration, but only in the colony with good breeding conditions. There was positive assortative mating by TL, however the degree of assortative mating was unrelated to mtDNAcn, cort levels and the probability of mate change, which greatly varied between the two colonies. Our results suggest that TL might be an indicator of the individual pace-of-life and may influence mating patterns. Importantly, contrasting environmental conditions influenced the link between TL and sexual coloration and the propensity of individuals to change mate, highlighting the importance of environmental variation on breeding strategies.

Brown boobies (Sula leucogaster) were studies in two colonies (Islas Marietas and Isla San Jorge, Mexico) to test whether telomere length (TL) may indicate individual pace-of-life by examining how it relates to mitochondrial DNA copy number (mtDNAcn), baseline corticosterone (cort) levels, and skin coloration—a condition-dependent sexual trait. We also tested whether there is assortative mating by TL, and whether the degree of TL similarity between partners influences an individual’s likelihood of changing mates and physiological state (mtDNAcn and cort levels).

A description of the variables is included in the file.