RESULTS
We found that growth rate (p = 0.893), brood size (p = 0.600), hatching order (p = 0.919), and sex (p = 0.749) had no influence on telomere dynamics (Table S3.1.2). Telomere length showed a negative correlation with mass index independent of age and treatment (p = 0.044; Fig 1, Table S3.2.2). Average telomere length showed an overall decline in our control birds over time (Fig 2). Telomeres at d5 were significantly longer compared to age d12 and 80 (p = 0.009 and p < 0.001 respectively), similarly to what we found for telomeres at age d12 compared to age d80 (p < 0.001; Table S3.2.2). Subjects exposed to the heat treatment showed no decline in telomere length between d 5 and d12, and between age d5 and d80 (p = 0.391), but had significantly shorter telomeres at day 80 compared to day 12 (p = 0.006; Fig 2; Table S3.2.2). Overall the heat treatment had no effect on telomere length (p = 0.278), but showed a significant interaction with age in determining telomere attrition (p < 0.001; Table S3.2.2). In particular between age 5 and 12, when the temperature treatment was taking place, telomere length decreased in our control, but in contrast actually showed an increase in the birds involved in the heat treatment (p = 0.031; Fig 2).
Parents of heated nests spent a mean±SE 75%±0.007 of their time brooding offspring, significantly less that the 85%±0.006 of time spend brooding by our control birds (p < 0.001; Fig 3, Table S5.2.2). We found a significant three-way interaction among the covariates showing higher brooding effort to be associated with longer nestling telomeres at 12 days of age for our heated birds (p = 0.016; Fig 4; Table S6.3.2).