155982 - Extreme polygyny results in intersex differences.pdf (538.46 kB)
Download fileExtreme polygyny results in intersex differences in age-dependent survival of a highly dimorphic marine mammal
journal contribution
posted on 2023-05-21, 17:12 authored by Sophia VolzkeSophia Volzke, Jaimie CleelandJaimie Cleeland, Mark HindellMark Hindell, Stuart CorneyStuart Corney, Wotherspoon, SJ, Clive McMahonClive McMahonDevelopmental differences in vital rates are especially profound in polygamous mating systems. Southern elephant seals (Mirounga leonina) are highly dimorphic and extremely polygynous marine mammals. A demographic model, supported by long-term capture–mark–recapture records, investigated the influence of sex and age on survival in this species. The study revealed clear differences between female and male age-dependent survival rates. Overall juvenile survival estimates were stable around 80–85% for both sexes. However, male survival estimates were 5–10% lower than females in the same age classes until 8 years of age. At this point, male survival decreased rapidly to 50% ± 10% while female estimates remained constant at 80% ± 5%. Different energetic requirements could underpin intersex differences in adult survival. However, the species' strong sexual dimorphism diverges during early juvenile development when sex-specific survival rates were less distinct. Maximizing growth is especially advantageous for males, with size being a major determinant of breeding probability. Maturing males may employ a high-risk high-reward foraging strategy to compensate for extensive sexual selection pressures and sex-specific energetic needs. Our findings suggest sex-specific adult survival is a result of in situ ecological interactions and evolutionary specialization associated with being a highly polygynous marine predator.
History
Publication title
Royal Society Open ScienceVolume
10Article number
221635Number
221635Pagination
1-9ISSN
2054-5703Department/School
Institute for Marine and Antarctic StudiesPublisher
The Royal Society PublishingPlace of publication
United KingdomRights statement
© 2023 The Authors. Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original author and source are credited.Repository Status
- Open