Table 2. The results of a phylogenetic model including all tested predictor variables. Coefficients show R values and are the result of back-transformed standardized Z-values. Species accounts for the repeated measures per species, phylogeny for the fact that these species are related, and laboratory identity for the fact that protocols are more similar within a laboratory. Fixed effects in italics show the variables for which the 95% CI did not overlap with zero. Intercept shows qPCR for average study length in a captive adult population of endotherm for a species with an average maximum lifespan. This table shows the model with all terms; a model without phylogeny or that contained only the terms in which 95% CI did not overlap with zero, gave consistent results (Table S1 A-D). l-95% CI and u-95% CI indicate lower and upper 95% confidence intervals, respectively.
Figure 1. Illustrating the variation in within-individual repeatability of telomere length. Simulated data is presented where population-level telomere shortening is constant (i.e. 1kb loss between time 1 and time 2) but within-individual repeatability is either (a) high (b) moderate or (c) low. Data has been simulated based on collared flycatcher telomere characteristics: mean ± SD = 18.6 ± 1.6kb, 1kb shortening occurring approximately over 2.5 years of life, N = 30, normal distribution (Stier et al. 2020). Black diagonals show x = y,i.e. when the telomere length at first and second measurement are the same, while dotted lines show regression lines for each dataset. Values above the diagonal illustrate telomere elongation (which can for example arise due to measurement error) and below the diagonal telomere shortening.