How does maternal age influence reproductive performance and offspring phenotype in the snow petrel (Pagodroma nivea)?

International audienceIn wild vertebrates, the increase of breeding success with advancing age has been extensively studied through layingdate, clutch size, hatching success, and fledging success. However, to better evaluate the influence of age on reproductiveperformance in species with high reproductive success, assessing not only reproductive success but also other proxies ofreproductive performance appear crucial. For example, the quality of developmental conditions and offspring phenotypecan provide robust and complementary information on reproductive performance. In long-lived vertebrate species, severalproxies of developmental conditions can be used to estimate the quality of the produced offspring (i.e., body size, body condition,corticosterone levels, and telomere length), and therefore, their probability to survive. By sampling chicks reared byknown-aged mothers, we investigated the influence of maternal age on reproductive performance and offspring quality in along-lived bird species, the snow petrel (Pagodroma nivea). Older females bred and left their chick alone earlier. Moreover,older females had larger chicks that grew faster, and ultimately, those chicks had a higher survival probability at the nest. Inaddition, older mothers produced chicks with a higher sensitivity to stress, as shown by moderately higher stress-inducedcorticosterone levels. Overall, our study demonstrated that maternal age is correlated to reproductive performance (hatchingdate, duration of the guarding period and survival) and offspring quality (body size, growth rate and sensitivity to stress),suggesting that older individuals provide better parental cares to their offspring. These results also demonstrate that maternalage can affect the offspring phenotype with potential long-term consequence