Traffic noise exposure affects telomere length in nestling house sparrows
Résumé
In a consistently urbanizing world, anthropogenic noise has become almost
omnipresent, and there are increasing evidence that high noise levels can
have major impacts on wildlife. While the effects of anthropogenic noise
exposure on adult animals have been widely studied, surprisingly, there
has been little consideration of the effects of noise pollution on developing
organisms. Yet, environmental conditions experienced in early life can have
dramatic lifelong consequences for fitness. Here, we experimentally manipulated
the acoustic environment of free-living house sparrows (Passer
domesticus) breeding in nest boxes. We focused on the impact of such disturbance
on nestlings’ telomere length and fledging success, as telomeres
(the protective ends of chromosomes) appear to be a promising predictor of
longevity.We showed that despite the absence of any obvious immediate consequences
(growth and fledging success), nestlings reared under traffic noise
exposure exhibited reduced telomere lengths compared with their unexposed
neighbours. Although the mechanisms responsible for this effect remain to
be determined, our results provide the first experimental evidence that noise
alone can affect a wild vertebrate’s early-life telomere length. This suggests
that noise exposure may entail important costs for developing organisms.