PT  - JOURNAL ARTICLE
AU  - Mirre J. P. Simons
AU  - Isabel Winney
AU  - Antje Girndt
AU  - Mark Rees
AU  - Shinichi Nakagawa
AU  - Julia Schroeder
AU  - Terry Burke
TI  - Ageing in house sparrows is insensitive to environmental effects
AID  - 10.1101/598284
DP  - 2019 Jan 01
TA  - bioRxiv
PG  - 598284
4099  - http://biorxiv.org/content/early/2019/04/04/598284.short
4100  - http://biorxiv.org/content/early/2019/04/04/598284.full
AB  - Variation in individual life histories, and physiology, determines the rates at which new life is generated (reproduction) and lost (death) in a population. Studying the demography of deaths thus reveals fundamental aspects of the biology of individuals within a population. We studied mortality senescence – the increase in mortality rate with age – in wild and captive house sparrows (Passer domesticus), and demonstrate highly similar mortality senescence in both, but markedly lower vulnerability to death (frailty) in captivity. This suggests that house sparrows have a species-specific rate of ageing that is insensitive to environmental effects. Unexpectedly, juvenile and adult mortality co-varied positively across years in the wild, indicating that mortality is not strongly density-dependent. Mortality also varied widely among years, suggesting a strong environmental effect, and we explain the observed patterns using temperature data and predation by birds of prey. We discuss how stochastic environmental effects can affect the evolution of ageing.