Egg sqize versus number of offspring trade-off: Female age rather than size matters in a domesticated arctic charr population

• Published in: Evolutionary Biology
• Main Authors: Lasne, Emilien, Leblanc, Camille Anne-Lise, Gillet, Christian
• Other Authors: Écologie et santé des écosystèmes (ESE), Institut National de la Recherche Agronomique (INRA)-AGROCAMPUS OUEST, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Centre Alpin de Recherche sur les Réseaux Trophiques et Ecosystèmes Limniques (CARRTEL), Institut National de la Recherche Agronomique (INRA)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry ), Department of Aquaculture and Fish Biology, Holar University College
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2018
• Subjects: life-history; reproductive trade-off; salmonid; offspring size; fecundity; [SDV.BDLR]Life Sciences [q-bio]/Reproductive Biology; Arctic; Arctic charr; Salvelinus alpinus
• Online Access: https://hal.inrae.fr/hal-02623395; https://doi.org/10.1007/s11692-017-9433-8

International audience Understanding how organisms adjust reproductive allocation trade-offs between offspring size versus number (OSN trade-off) is a central question in evolutionary biology. In organisms with indeterminate growth, changes in OSN according to maternal size or age have been reported in numerous taxa. The relative contribution of age and size remains largely unclear, as they are often highly correlated. In this study, we investigated how females adjust the offspring size versus number trade-off and analyzed the relative contribution of female age and size in a domesticated population of Arctic charr Salvelinus alpinus (Linnaeus, 1758) that exhibit large variation in size within five age classes. Our results show that the reproductive output (i.e. as measured by the clutch mass), was strongly correlated to female mass and age suggesting that the proportion of resources allocated to reproduction do not vary along lifetime. Egg mass and fecundity (egg number) increased with female mass overall. However, within an age class, larger females had higher fecundity but egg mass was poorly related to female mass. At the population level, a positive relationship was observed between fecundity and egg mass but within each class age the relation was negative revealing a OSN trade-off. Overall, our results show that, in our model Arctic charr population, allocation trade-off to reproduction and the way females allocate to egg mass and fecundity is largely determined by their age rather than mass.