Meeting Abstract
Early life stress can have long-term effects on many phenotypic qualities, including telomere dynamics. Telomeres are the guanine-rich, protective ends of chromosomes that shorten with accelerated growth and exposure to stressors, and prior work suggests that telomeres in male and female animals may differ in sensitivity to stress. Here, we tested how a mild maternal stressor influences offspring telomere dynamics during postnatal development in tree swallows (Tachycineta bicolor) and asked whether sex predicts the effects of stress on a suite of traits. Specifically, when chicks were 5 days old, we injected mothers with either saline or lipopolysaccharide (LPS), which elicits a 24h sickness response. In the week following treatment, we measured chick growth, telomere length, and restraint-induced corticosterone (CORT). We found that within 24h post-injection, LPS females decreased nest visitation rate, resulting in a short-term reduction in chick growth relative to controls. Consequently, telomere dynamics differed between treatments, and stronger effects were observed in males. Males from LPS nests also exhibited dampened stress reactivity (i.e. CORT elevation), which was positively correlated with telomere length, suggesting that changes in telomere length may be mediated by CORT. However, chicks from experimental and control nests did not differ in morphology at 12 days old, suggesting that stress-exposed chicks may carry cryptic physiological variation that could manifest later in life. While additional research is necessary to identify the mechanisms underlying these sex-specific patterns, our results provide novel insights into sex-specific vulnerability to early-life stress.
