Productive foraging sites enhance maternal health and impact offspring fitness in a capital breeding species

Abstract

Feeding ecology is an essential component of an organism’s life, but foraging comes with risks and energetic costs. Species in which populations exhibit more than one feeding strategy, such as sea turtles, are good systems for investigating how feeding ecology impacts life-history traits, reproduction and carried over effects across generations. Here, we investigated how the feeding ecology of loggerhead sea turtles (Caretta caretta) nesting at the Cabo Verde archipelago correlates with reproductive outputs and offspring fitness. We determined the feeding ecology of female turtles before and during the breeding season from stable isotope analysis of carbon and nitrogen, and correlated isotopic ratio with female and hatchling fitness traits. We found that female turtles feeding at higher trophic positions produced larger clutches. We also found that females with less depleted δ13C values, typical of productive foraging areas, had greater fat reserves, were less likely to be infected by leech parasites, and produced heavier offspring. The offspring of infected mothers with less depleted δ13C values performed best in crawling and self-righting trials than those of non-infected mothers with less depleted δ13C values. Overall, our study shows adult female loggerheads that exploit productive areas build capital reserves that impact their reproductive success and offspring fitness. Together, we uphold the suggestion that not all foraging habitats are equal, and can alter the fitness of populations.