Early‐life seasonal, weather and social effects on telomere length in a wild mammal

Early-life environmental conditions can provide a source of individual
variation in life-history strategies and senescence patterns. Conditions
experienced in early life can be quantified by measuring telomere length,
which can act as a biomarker of survival probability in some species.
Here, we investigate whether seasonal changes, weather conditions, and
group size are associated with early-life and/or early-adulthood telomere
length in a wild population of European badgers (Meles meles). We found
substantial intra-annual changes in telomere length during the first three
years of life (both between and within individuals), with shorter telomere
lengths in the winter following the first spring and a trend for longer
telomere lengths in the second spring compared to the first winter. In
terms of weather conditions, cubs born in warmer, wetter springs with low
rainfall variability had longer early-life (3–12 months old) telomere
lengths. Additionally, cubs born in groups with more cubs had marginally
longer early-life telomeres, providing no evidence of resource constraint
from cub competition. We also found that our previously documented
positive association between early-life telomere length and cub survival
probability remained when social and weather variables were included.
Finally, after sexual maturity, in early adulthood (i.e. 12–36 months) we
found no significant association between same-sex adult group size and
telomere length (i.e. no effect of intra-sexual competition). Overall, we
show that controlling for seasonal effects, which are linked to food
availability and foraging success, is important in telomere length
analyses, and that variation in telomere length in badgers reflects
early-life conditions and also predicts first year cub survival.