Sperm Numbers as a Paternity Guard in a Wild Bird
Sperm competition is thought to impose strong selection on males to produce competitive ejaculates to outcompete rival males under competitive mating conditions. Our understanding of how different sperm traits influence fertilization success, however, remains limited, especially in wild populations....
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-01-01
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| Series: | Cells |
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| Online Access: | https://www.mdpi.com/2073-4409/11/2/231 |
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| author | Melissah Rowe Annabel van Oort Lyanne Brouwer Jan T. Lifjeld Michael S. Webster Joseph F. Welklin Daniel T. Baldassarre |
| author_facet | Melissah Rowe Annabel van Oort Lyanne Brouwer Jan T. Lifjeld Michael S. Webster Joseph F. Welklin Daniel T. Baldassarre |
| author_sort | Melissah Rowe |
| collection | DOAJ |
| description | Sperm competition is thought to impose strong selection on males to produce competitive ejaculates to outcompete rival males under competitive mating conditions. Our understanding of how different sperm traits influence fertilization success, however, remains limited, especially in wild populations. Recent literature highlights the importance of incorporating multiple ejaculate traits and pre-copulatory sexually selected traits in analyses aimed at understanding how selection acts on sperm traits. However, variation in a male’s ability to gain fertilization success may also depend upon a range of social and ecological factors that determine the opportunity for mating events both within and outside of the social pair-bond. Here, we test for an effect of sperm quantity and sperm size on male reproductive success in the red-back fairy-wren (<i>Malurus melanocephalus</i>) while simultaneously accounting for pre-copulatory sexual selection and potential socio-ecological correlates of male mating success. We found that sperm number (i.e., cloacal protuberance volume), but not sperm morphology, was associated with reproductive success in male red-backed fairy-wrens. Most notably, males with large numbers of sperm available for copulation achieved greater within-pair paternity success. Our results suggest that males use large sperm numbers as a defensive strategy to guard within-pair paternity success in a system where there is a high risk of sperm competition and female control of copulation. Finally, our work highlights the importance of accounting for socio-ecological factors that may influence male mating opportunities when examining the role of sperm traits in determining male reproductive success. |
| first_indexed | 2024-03-10T01:44:33Z |
| format | Article |
| id | doaj.art-b84c96696f7340f2a74c357fda3a5170 |
| institution | Directory Open Access Journal |
| issn | 2073-4409 |
| language | English |
| last_indexed | 2024-03-10T01:44:33Z |
| publishDate | 2022-01-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Cells |
| spelling | doaj.art-b84c96696f7340f2a74c357fda3a51702023-11-23T13:18:11ZengMDPI AGCells2073-44092022-01-0111223110.3390/cells11020231Sperm Numbers as a Paternity Guard in a Wild BirdMelissah Rowe0Annabel van Oort1Lyanne Brouwer2Jan T. Lifjeld3Michael S. Webster4Joseph F. Welklin5Daniel T. Baldassarre6Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), 6700 AB Wageningen, The NetherlandsDepartment of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), 6700 AB Wageningen, The NetherlandsCollege of Science & Engineering, James Cook University, Townsville, QLD 4811, AustraliaSex and Evolution Research Group, Natural History Museum, University of Oslo, 0318 Oslo, NorwayCornell Lab of Ornithology, and Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14850, USACornell Lab of Ornithology, and Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14850, USADepartment of Biological Sciences, SUNY Oswego, Oswego, NY 13126, USASperm competition is thought to impose strong selection on males to produce competitive ejaculates to outcompete rival males under competitive mating conditions. Our understanding of how different sperm traits influence fertilization success, however, remains limited, especially in wild populations. Recent literature highlights the importance of incorporating multiple ejaculate traits and pre-copulatory sexually selected traits in analyses aimed at understanding how selection acts on sperm traits. However, variation in a male’s ability to gain fertilization success may also depend upon a range of social and ecological factors that determine the opportunity for mating events both within and outside of the social pair-bond. Here, we test for an effect of sperm quantity and sperm size on male reproductive success in the red-back fairy-wren (<i>Malurus melanocephalus</i>) while simultaneously accounting for pre-copulatory sexual selection and potential socio-ecological correlates of male mating success. We found that sperm number (i.e., cloacal protuberance volume), but not sperm morphology, was associated with reproductive success in male red-backed fairy-wrens. Most notably, males with large numbers of sperm available for copulation achieved greater within-pair paternity success. Our results suggest that males use large sperm numbers as a defensive strategy to guard within-pair paternity success in a system where there is a high risk of sperm competition and female control of copulation. Finally, our work highlights the importance of accounting for socio-ecological factors that may influence male mating opportunities when examining the role of sperm traits in determining male reproductive success.https://www.mdpi.com/2073-4409/11/2/231fairy-wrenpost-copulatory sexual selectionsperm competitionsperm morphology<i>Malurus</i> |
| spellingShingle | Melissah Rowe Annabel van Oort Lyanne Brouwer Jan T. Lifjeld Michael S. Webster Joseph F. Welklin Daniel T. Baldassarre Sperm Numbers as a Paternity Guard in a Wild Bird Cells fairy-wren post-copulatory sexual selection sperm competition sperm morphology <i>Malurus</i> |
| title | Sperm Numbers as a Paternity Guard in a Wild Bird |
| title_full | Sperm Numbers as a Paternity Guard in a Wild Bird |
| title_fullStr | Sperm Numbers as a Paternity Guard in a Wild Bird |
| title_full_unstemmed | Sperm Numbers as a Paternity Guard in a Wild Bird |
| title_short | Sperm Numbers as a Paternity Guard in a Wild Bird |
| title_sort | sperm numbers as a paternity guard in a wild bird |
| topic | fairy-wren post-copulatory sexual selection sperm competition sperm morphology <i>Malurus</i> |
| url | https://www.mdpi.com/2073-4409/11/2/231 |
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