| Literature DB >> 31039729 |
Dorinda Marie Folio1, Jon Aars2, Olivier Gimenez1, Andrew E Derocher3, Øystein Wiig4, Sarah Cubaynes1,5.
Abstract
Life-history theory predicts that females' age and size affect the level of maternal investment in current reproduction, balanced against the future reproductive effort, maintenance and survival. Using long-term (30 years) individual data on 193 female polar bears ( Ursus maritimus), we assessed age- and size-specific variation on litter size. Litter size varied with maternal age, younger females had higher chances of losing a cub during their first months of life. Results suggest an improvement in reproductive abilities early in life due to experience with subsequent reproductive senescence. Litter size increased with maternal size, indicating that size may reflect individual quality. We also found an optimum in the probability of having twins, suggesting stabilizing selection on female body size. Heterogeneity was observed among the largest females, suggesting that large size comes at a cost.Entities:
Keywords: individual heterogeneity; maternal traits; polar bear; reproductive senescence; reproductive success
Mesh：
Year: 2019 PMID： 31039729 PMCID： PMC6548740 DOI： 10.1098/rsbl.2019.0070
Source DB: PubMed Journal: Biol Lett ISSN： 1744-9561 Impact factor: 3.703