Meeting Abstract
The natal environment can influence an organism’s survival and reproductive success. Telomere length is demonstrated to co-vary with measures of organismal performance, and telomere dynamics early in life may have long-lasting consequences. Therefore, it is important to understand the sources of variation in telomere length. We investigated the relative contributions of genetic vs. environmental effects on variation in telomere length in nestling barn swallows (Hirundo rustica erythrogaster) using an egg-cross foster experiment. Half of the eggs in nests were switched with synchronously laid eggs from different nests. This design, and the fact that broods contain mixed paternity, allows us to decouple genetic and environmental effects on telomere length. Female incubation behavior was quantified with thermocouple eggs that record incubation temperature profiles. We measured relative telomere length of nine-day old nestlings using qPCR, assigned parentage of nestlings using microsatellite markers, and used an animal model to investigate heritability. A substantial amount of variation in telomere length could be attributed to additive genetic variance; however, the nest environment also explained a significant amount of overall phenotypic variance. We predicted that eggs receiving consistent, high-quality incubation would result in nestlings with relatively longer telomeres compared to eggs with a less consistent, lower-quality incubation. Our results support our hypothesis; eggs experiencing a higher mean temperature, especially early in incubation, resulted in nestlings with longer telomeres relative to nestlings from eggs incubated at lower mean temperatures.
