Measures of breeding inequality: a case study in southern elephant seals
Inequality in distribution of resources is a key aspect of evolutionary biology particularly in relation to distribution of mates and copulations. Notwithstanding its important role, inequality is not easily defined, and its measurement is complicated by theoretical and methodological issues. Althou...
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crcansciencepubl:10.1139/z02-117 2024-09-15T18:04:39+00:00 Measures of breeding inequality: a case study in southern elephant seals Galimberti, Filippo Fabiani, Anna Sanvito, Simona 2002 http://dx.doi.org/10.1139/z02-117 http://www.nrcresearchpress.com/doi/pdf/10.1139/z02-117 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Canadian Journal of Zoology volume 80, issue 7, page 1240-1249 ISSN 0008-4301 1480-3283 journal-article 2002 crcansciencepubl https://doi.org/10.1139/z02-117 2024-08-15T04:09:30Z Inequality in distribution of resources is a key aspect of evolutionary biology particularly in relation to distribution of mates and copulations. Notwithstanding its important role, inequality is not easily defined, and its measurement is complicated by theoretical and methodological issues. Although the formal treatment of inequality has been mostly limited to the evolution of lek mating system, a methodologically correct approach to measurement of inequality is generally valid for the study of any kind of mating system. In this paper, we analyze inequality in a large set of southern elephant seal (Mirounga leonina) harems. The observed distribution of fertilizations was significantly different from both the expected distribution with equal shares of resources and the expected distribution with equal propensities to acquire resources. We calculate and compare various measures of inequality, observing a wide variation particularly among unbounded and bounded indices. We check the effect of choosing a specific measure of inequality by considering the effect of two aspects of harem socionomy, the number of females in the harem (i.e., the total amount of resources to be shared) and the number of males associated with the harem (i.e., the number of competitors). The choice of a specific measure of inequality had a strong impact on the results obtained and should be considered a critical step in every study of functional and evolutionary correlates of inequality. Unbounded indices showed a strong relationship with both harem size and number of males, while no effect was evident in the analysis of bounded indices. This demonstrates that, in this species, the despotism of the mating system remains high even in large harems and with many competitors, i.e., the worst conditions for monopolization. Article in Journal/Newspaper Elephant Seal Elephant Seals Mirounga leonina Southern Elephant Seal Southern Elephant Seals Canadian Science Publishing Canadian Journal of Zoology 80 7 1240 1249 |
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Canadian Science Publishing |
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Inequality in distribution of resources is a key aspect of evolutionary biology particularly in relation to distribution of mates and copulations. Notwithstanding its important role, inequality is not easily defined, and its measurement is complicated by theoretical and methodological issues. Although the formal treatment of inequality has been mostly limited to the evolution of lek mating system, a methodologically correct approach to measurement of inequality is generally valid for the study of any kind of mating system. In this paper, we analyze inequality in a large set of southern elephant seal (Mirounga leonina) harems. The observed distribution of fertilizations was significantly different from both the expected distribution with equal shares of resources and the expected distribution with equal propensities to acquire resources. We calculate and compare various measures of inequality, observing a wide variation particularly among unbounded and bounded indices. We check the effect of choosing a specific measure of inequality by considering the effect of two aspects of harem socionomy, the number of females in the harem (i.e., the total amount of resources to be shared) and the number of males associated with the harem (i.e., the number of competitors). The choice of a specific measure of inequality had a strong impact on the results obtained and should be considered a critical step in every study of functional and evolutionary correlates of inequality. Unbounded indices showed a strong relationship with both harem size and number of males, while no effect was evident in the analysis of bounded indices. This demonstrates that, in this species, the despotism of the mating system remains high even in large harems and with many competitors, i.e., the worst conditions for monopolization. |
format |
Article in Journal/Newspaper |
author |
Galimberti, Filippo Fabiani, Anna Sanvito, Simona |
spellingShingle |
Galimberti, Filippo Fabiani, Anna Sanvito, Simona Measures of breeding inequality: a case study in southern elephant seals |
author_facet |
Galimberti, Filippo Fabiani, Anna Sanvito, Simona |
author_sort |
Galimberti, Filippo |
title |
Measures of breeding inequality: a case study in southern elephant seals |
title_short |
Measures of breeding inequality: a case study in southern elephant seals |
title_full |
Measures of breeding inequality: a case study in southern elephant seals |
title_fullStr |
Measures of breeding inequality: a case study in southern elephant seals |
title_full_unstemmed |
Measures of breeding inequality: a case study in southern elephant seals |
title_sort |
measures of breeding inequality: a case study in southern elephant seals |
publisher |
Canadian Science Publishing |
publishDate |
2002 |
url |
http://dx.doi.org/10.1139/z02-117 http://www.nrcresearchpress.com/doi/pdf/10.1139/z02-117 |
genre |
Elephant Seal Elephant Seals Mirounga leonina Southern Elephant Seal Southern Elephant Seals |
genre_facet |
Elephant Seal Elephant Seals Mirounga leonina Southern Elephant Seal Southern Elephant Seals |
op_source |
Canadian Journal of Zoology volume 80, issue 7, page 1240-1249 ISSN 0008-4301 1480-3283 |
op_rights |
http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/z02-117 |
container_title |
Canadian Journal of Zoology |
container_volume |
80 |
container_issue |
7 |
container_start_page |
1240 |
op_container_end_page |
1249 |
_version_ |
1810442273085718528 |