Sex‐specific demography and generalization of the Trivers–Willard theory
The Trivers–Willard theory proposes that the sex ratio of offspring should vary with maternal condition when it has sex‐specific influences on offspring fitness. In particular, mothers in good condition in polygynous and dimorphic species are predicted to produce an excess of sons, whereas mothers i...
| Main Authors: | , , , , , , |
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| Format: | Journal article |
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Nature Publishing Group
2015
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| _version_ | 1797069931818254336 |
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| author | Schindler, S Gaillard, J Grüning, A Neuhaus, P Traill, L Tuljapurkar, S Coulson, T |
| author_facet | Schindler, S Gaillard, J Grüning, A Neuhaus, P Traill, L Tuljapurkar, S Coulson, T |
| author_sort | Schindler, S |
| collection | OXFORD |
| description | The Trivers–Willard theory proposes that the sex ratio of offspring should vary with maternal condition when it has sex‐specific influences on offspring fitness. In particular, mothers in good condition in polygynous and dimorphic species are predicted to produce an excess of sons, whereas mothers in poor condition should do the opposite. Despite the elegance of the theory, support for it has been limited. Here we extend and generalize the Trivers–Willard theory to explain the disparity between predictions and observations of offspring sex ratio. In polygynous species, males typically have higher mortality rates, different age‐specific reproductive schedules and more risk‐prone life history tactics than females; however, these differences are not currently incorporated into the Trivers–Willard theory. Using two‐sex models parameterized with data from free‐living mammal populations with contrasting levels of sex differences in demography, we demonstrate how sex differences in life history traits over the entire lifespan can lead to a wide range of sex allocation tactics, and show that correlations between maternal condition and offspring sex ratio alone are insufficient to conclude that mothers adaptively adjust offspring sex ratio. |
| first_indexed | 2024-03-06T22:31:42Z |
| format | Journal article |
| id | oxford-uuid:587ef425-5299-4e5a-b929-7e21a35566c6 |
| institution | University of Oxford |
| last_indexed | 2024-03-06T22:31:42Z |
| publishDate | 2015 |
| publisher | Nature Publishing Group |
| record_format | dspace |
| spelling | oxford-uuid:587ef425-5299-4e5a-b929-7e21a35566c62022-03-26T17:03:46ZSex‐specific demography and generalization of the Trivers–Willard theoryJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:587ef425-5299-4e5a-b929-7e21a35566c6Symplectic Elements at OxfordNature Publishing Group2015Schindler, SGaillard, JGrüning, ANeuhaus, PTraill, LTuljapurkar, SCoulson, TThe Trivers–Willard theory proposes that the sex ratio of offspring should vary with maternal condition when it has sex‐specific influences on offspring fitness. In particular, mothers in good condition in polygynous and dimorphic species are predicted to produce an excess of sons, whereas mothers in poor condition should do the opposite. Despite the elegance of the theory, support for it has been limited. Here we extend and generalize the Trivers–Willard theory to explain the disparity between predictions and observations of offspring sex ratio. In polygynous species, males typically have higher mortality rates, different age‐specific reproductive schedules and more risk‐prone life history tactics than females; however, these differences are not currently incorporated into the Trivers–Willard theory. Using two‐sex models parameterized with data from free‐living mammal populations with contrasting levels of sex differences in demography, we demonstrate how sex differences in life history traits over the entire lifespan can lead to a wide range of sex allocation tactics, and show that correlations between maternal condition and offspring sex ratio alone are insufficient to conclude that mothers adaptively adjust offspring sex ratio. |
| spellingShingle | Schindler, S Gaillard, J Grüning, A Neuhaus, P Traill, L Tuljapurkar, S Coulson, T Sex‐specific demography and generalization of the Trivers–Willard theory |
| title | Sex‐specific demography and generalization of the Trivers–Willard theory |
| title_full | Sex‐specific demography and generalization of the Trivers–Willard theory |
| title_fullStr | Sex‐specific demography and generalization of the Trivers–Willard theory |
| title_full_unstemmed | Sex‐specific demography and generalization of the Trivers–Willard theory |
| title_short | Sex‐specific demography and generalization of the Trivers–Willard theory |
| title_sort | sex specific demography and generalization of the trivers willard theory |
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