Contrasting effects of large density changes on relative testes size in fluctuating populations of sympatric vole species
Across species, there is usually a positive relationship between sperm competition level and male reproductive effort on ejaculates, typically measured using relative testes size (RTS). Within populations, demographic and ecological processes may drastically alter the level of sperm competition and...
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crroyalsociety:10.1098/rspb.2014.1291 2024-06-02T08:06:32+00:00 Contrasting effects of large density changes on relative testes size in fluctuating populations of sympatric vole species Klemme, Ines Soulsbury, Carl D. Henttonen, Heikki 2014 http://dx.doi.org/10.1098/rspb.2014.1291 https://royalsocietypublishing.org/doi/pdf/10.1098/rspb.2014.1291 https://royalsocietypublishing.org/doi/full-xml/10.1098/rspb.2014.1291 en eng The Royal Society https://royalsociety.org/journals/ethics-policies/data-sharing-mining/ Proceedings of the Royal Society B: Biological Sciences volume 281, issue 1792, page 20141291 ISSN 0962-8452 1471-2954 journal-article 2014 crroyalsociety https://doi.org/10.1098/rspb.2014.1291 2024-05-07T14:16:16Z Across species, there is usually a positive relationship between sperm competition level and male reproductive effort on ejaculates, typically measured using relative testes size (RTS). Within populations, demographic and ecological processes may drastically alter the level of sperm competition and thus, potentially affect the evolution of testes size. Here, we use longitudinal records (across 38 years) from wild sympatric Fennoscandian populations of five species of voles to investigate whether RTS responds to natural fluctuations in population density, i.e. variation in sperm competition risk. We show that for some species RTS increases with density. However, our results also show that this relationship can be reversed in populations with large-scale between-year differences in density. Multiple mechanisms are suggested to explain the negative RTS–density relationship, including testes size response to density-dependent species interactions, an evolutionary response to sperm competition levels that is lagged when density fluctuations are over a certain threshold, or differing investment in pre- and post-copulatory competition at different densities. The results emphasize that our understanding of sperm competition in fluctuating environments is still very limited. Article in Journal/Newspaper Fennoscandian The Royal Society Proceedings of the Royal Society B: Biological Sciences 281 1792 20141291 |
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English |
description |
Across species, there is usually a positive relationship between sperm competition level and male reproductive effort on ejaculates, typically measured using relative testes size (RTS). Within populations, demographic and ecological processes may drastically alter the level of sperm competition and thus, potentially affect the evolution of testes size. Here, we use longitudinal records (across 38 years) from wild sympatric Fennoscandian populations of five species of voles to investigate whether RTS responds to natural fluctuations in population density, i.e. variation in sperm competition risk. We show that for some species RTS increases with density. However, our results also show that this relationship can be reversed in populations with large-scale between-year differences in density. Multiple mechanisms are suggested to explain the negative RTS–density relationship, including testes size response to density-dependent species interactions, an evolutionary response to sperm competition levels that is lagged when density fluctuations are over a certain threshold, or differing investment in pre- and post-copulatory competition at different densities. The results emphasize that our understanding of sperm competition in fluctuating environments is still very limited. |
format |
Article in Journal/Newspaper |
author |
Klemme, Ines Soulsbury, Carl D. Henttonen, Heikki |
spellingShingle |
Klemme, Ines Soulsbury, Carl D. Henttonen, Heikki Contrasting effects of large density changes on relative testes size in fluctuating populations of sympatric vole species |
author_facet |
Klemme, Ines Soulsbury, Carl D. Henttonen, Heikki |
author_sort |
Klemme, Ines |
title |
Contrasting effects of large density changes on relative testes size in fluctuating populations of sympatric vole species |
title_short |
Contrasting effects of large density changes on relative testes size in fluctuating populations of sympatric vole species |
title_full |
Contrasting effects of large density changes on relative testes size in fluctuating populations of sympatric vole species |
title_fullStr |
Contrasting effects of large density changes on relative testes size in fluctuating populations of sympatric vole species |
title_full_unstemmed |
Contrasting effects of large density changes on relative testes size in fluctuating populations of sympatric vole species |
title_sort |
contrasting effects of large density changes on relative testes size in fluctuating populations of sympatric vole species |
publisher |
The Royal Society |
publishDate |
2014 |
url |
http://dx.doi.org/10.1098/rspb.2014.1291 https://royalsocietypublishing.org/doi/pdf/10.1098/rspb.2014.1291 https://royalsocietypublishing.org/doi/full-xml/10.1098/rspb.2014.1291 |
genre |
Fennoscandian |
genre_facet |
Fennoscandian |
op_source |
Proceedings of the Royal Society B: Biological Sciences volume 281, issue 1792, page 20141291 ISSN 0962-8452 1471-2954 |
op_rights |
https://royalsociety.org/journals/ethics-policies/data-sharing-mining/ |
op_doi |
https://doi.org/10.1098/rspb.2014.1291 |
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Proceedings of the Royal Society B: Biological Sciences |
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281 |
container_issue |
1792 |
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20141291 |
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1800751485477191680 |