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.