Social and nutritional factors associated with female reproductive output in Yellow-bellied marmots (Marmota flaviventris) [Facteurs sociaux et nutritionnel associés aux résultats reproductifs de femelles chez les marmottes à ventre jaune].

Résumé

I studied social behavior and female reproductive output (RO) among free-living yellow-bellied marmots (Marmota flaviventris). First, I determined whether there is evidence for competition among females over either food or burrows and whether social factors affect female body condition. Females do apparently compete over food. Females also tend to initiate agonism near their own burrows, but no more likely than expected based on the amount of time they spend near their burrows. Crowded females have lower body condition (rate of increase in body mass index, BMI) than relatively isolated females. Next, I investigated whether social or nutritional factors predict female RO. As expected, females in better body condition, and those living in relative isolation, during 1 summer were more likely to wean offspring the next year. The mean estimated relatedness among neighboring females during 1 summer was not associated with the likelihood of weaning offspring the next year. For those females that did wean alitter, mean relatedness of nearby females was positively correlated with mass of kids born in the current season.