Väitös (evoluutiobiologia): MSc Héloïse Moullec

MSc Héloïse Moullec esittää väitöskirjansa ”Ageing in the wild: insights on the diversity and determinants in two long-lived vertebrates” julkisesti tarkastettavaksi Turun yliopistossa perjantaina 8.5.2026 klo 12.15 (Turun yliopisto, päärakennus, Tauno Nurmela -sali, Turku).

Vastaväittäjänä toimii professori Jan-Åke Nilsson (Lundin yliopisto, Ruotsi) ja kustoksena professori Jon Brommer (Turun yliopisto). Tilaisuus on englanninkielinen. Väitöksen alana on evoluutiobiologia.

Tiivistelmä väitöstutkimuksesta:

Ageing, the physical and physiological decline of an organism with age, is a common phenomenon in the animal kingdom. Yet, within species, some individuals live longer and age more slowly than others. Understanding this diversity remains a major challenge, especially in wild populations exposed to constantly changing environmental conditions. In this thesis, I used data from two long-lived species, the Asian elephant and the Alpine swift, to identify what determines ageing and lifespan diversity in the wild.

First, I investigated how Alpine swifts’ body measurements (wing, tail, fork, sternum length, body mass), reproductive success (number of offspring produced), and number of blood-sucking parasites in their plumage vary with age. I found a clear decline with age in most of these traits. However, the beginning and intensity of the decline varied widely among traits and between males and females. For instance, reproductive success declined with age in females, but not in males.

Building on these results, I then studied whether reproducing at an older age affects the next generation. I found that older mothers and fathers produced larger offspring, but that older fathers produced sons with more parasites and a shorter lifespan. This suggests that ageing can have negative effects that extend across generations.

Finally, I investigated whether the diversity of lifespan in the Asian elephant population has a genetic basis. I found that lifespan in both males and females is heritable. In other words, individual variation in lifespan in this population is partially explained by inherited genetic differences.

Across all chapters of my thesis, the environmental conditions experienced by individuals throughout their lives also appeared to significantly affect lifespan. Overall, this thesis demonstrates that ageing and lifespan diversity arise from the combined influence of genetic factors, parental effects, sex, and environmental conditions experienced across the lifespan.