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Unimodal head-width distribution of the European eel (Anguilla anguilla L.) from the Zeeschelde does not support disruptive selection

Since the early 20th century, European eels (Anguilla anguilla L.) have been dichotomously classified into ‘narrow’ and ‘broad’ heads. These morphs are mainly considered the result of a differential food choice, with narrow heads feeding primarily on small/soft prey and broad heads on large/hard pre...

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Autores principales: Verhelst, Pieterjan, De Meyer, Jens, Reubens, Jan, Coeck, Johan, Goethals, Peter, Moens, Tom, Mouton, Ans
Formato: Online Artículo Texto
Lenguaje:English
Publicado: PeerJ Inc. 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6225841/
https://www.ncbi.nlm.nih.gov/pubmed/30416881
http://dx.doi.org/10.7717/peerj.5773
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author Verhelst, Pieterjan
De Meyer, Jens
Reubens, Jan
Coeck, Johan
Goethals, Peter
Moens, Tom
Mouton, Ans
author_facet Verhelst, Pieterjan
De Meyer, Jens
Reubens, Jan
Coeck, Johan
Goethals, Peter
Moens, Tom
Mouton, Ans
author_sort Verhelst, Pieterjan
collection PubMed
description Since the early 20th century, European eels (Anguilla anguilla L.) have been dichotomously classified into ‘narrow’ and ‘broad’ heads. These morphs are mainly considered the result of a differential food choice, with narrow heads feeding primarily on small/soft prey and broad heads on large/hard prey. Yet, such a classification implies that head-width variation follows a bimodal distribution, leading to the assumption of disruptive selection. We investigated the head morphology of 272 eels, caught over three consecutive years (2015–2017) at a single location in the Zeeschelde (Belgium). Based on our results, BIC favored a unimodal distribution, while AIC provided equal support for a unimodal and a bimodal distribution. Notably, visualization of the distributions revealed a strong overlap between the two normal distributions under the bimodal model, likely explaining the ambiguity under AIC. Consequently, it is more likely that head-width variation followed a unimodal distribution, indicating there are no disruptive selection pressures for bimodality in the Zeeschelde. As such, eels could not be divided in two distinct head-width groups. Instead, their head widths showed a continuum of narrow to broad with a normal distribution. This pattern was consistent across all maturation stages studied here.
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spelling pubmed-62258412018-11-09 Unimodal head-width distribution of the European eel (Anguilla anguilla L.) from the Zeeschelde does not support disruptive selection Verhelst, Pieterjan De Meyer, Jens Reubens, Jan Coeck, Johan Goethals, Peter Moens, Tom Mouton, Ans PeerJ Animal Behavior Since the early 20th century, European eels (Anguilla anguilla L.) have been dichotomously classified into ‘narrow’ and ‘broad’ heads. These morphs are mainly considered the result of a differential food choice, with narrow heads feeding primarily on small/soft prey and broad heads on large/hard prey. Yet, such a classification implies that head-width variation follows a bimodal distribution, leading to the assumption of disruptive selection. We investigated the head morphology of 272 eels, caught over three consecutive years (2015–2017) at a single location in the Zeeschelde (Belgium). Based on our results, BIC favored a unimodal distribution, while AIC provided equal support for a unimodal and a bimodal distribution. Notably, visualization of the distributions revealed a strong overlap between the two normal distributions under the bimodal model, likely explaining the ambiguity under AIC. Consequently, it is more likely that head-width variation followed a unimodal distribution, indicating there are no disruptive selection pressures for bimodality in the Zeeschelde. As such, eels could not be divided in two distinct head-width groups. Instead, their head widths showed a continuum of narrow to broad with a normal distribution. This pattern was consistent across all maturation stages studied here. PeerJ Inc. 2018-11-06 /pmc/articles/PMC6225841/ /pubmed/30416881 http://dx.doi.org/10.7717/peerj.5773 Text en ©2018 Verhelst et al. http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ) and either DOI or URL of the article must be cited.
spellingShingle Animal Behavior
Verhelst, Pieterjan
De Meyer, Jens
Reubens, Jan
Coeck, Johan
Goethals, Peter
Moens, Tom
Mouton, Ans
Unimodal head-width distribution of the European eel (Anguilla anguilla L.) from the Zeeschelde does not support disruptive selection
title Unimodal head-width distribution of the European eel (Anguilla anguilla L.) from the Zeeschelde does not support disruptive selection
title_full Unimodal head-width distribution of the European eel (Anguilla anguilla L.) from the Zeeschelde does not support disruptive selection
title_fullStr Unimodal head-width distribution of the European eel (Anguilla anguilla L.) from the Zeeschelde does not support disruptive selection
title_full_unstemmed Unimodal head-width distribution of the European eel (Anguilla anguilla L.) from the Zeeschelde does not support disruptive selection
title_short Unimodal head-width distribution of the European eel (Anguilla anguilla L.) from the Zeeschelde does not support disruptive selection
title_sort unimodal head-width distribution of the european eel (anguilla anguilla l.) from the zeeschelde does not support disruptive selection
topic Animal Behavior
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6225841/
https://www.ncbi.nlm.nih.gov/pubmed/30416881
http://dx.doi.org/10.7717/peerj.5773
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