Hormonal pathways have been proposed to be key at modulating how fast individuals
grow and reproduce and how long they live (i.e., life history trajectory). Research
in model species living under controlled environment is suggesting that insulin-like
growth factor 1 (IGF-1), which is an evolutionarily conserved polypeptide hormone,
has an important role in modulating animal life histories. Much remains, however,
to be done to test the role played by IGF-1 in shaping the phenotype and life history
of animals in the wild. Using a wild long-lived bird, the Alpine swift (Tachymarptis
melba), we show that adults with higher levels of IGF-1 had longer wings and shorter
telomeres. Hence, telomeres being a proxy of lifespan in this species, our results
support a potential role of IGF-1 at shaping the life-history of wild birds and suggest
that IGF-1 may influence the growth-lifespan trade-off.
