Cargando…
Sex differences in behavioural and anatomical estimates of visual acuity in the green swordtail, Xiphophorus helleri
Among fishes in the family Poeciliidae, signals such as colour patterns, ornaments and courtship displays play important roles in mate choice and male–male competition. Despite this, visual capabilities in poeciliids are understudied, in particular, visual acuity, the ability to resolve detail. We u...
Autores principales: | , , |
---|---|
Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
The Company of Biologists Ltd
2021
|
Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8729911/ https://www.ncbi.nlm.nih.gov/pubmed/34787303 http://dx.doi.org/10.1242/jeb.243420 |
_version_ | 1784627019607179264 |
---|---|
author | Caves, Eleanor M. de Busserolles, Fanny Kelley, Laura A. |
author_facet | Caves, Eleanor M. de Busserolles, Fanny Kelley, Laura A. |
author_sort | Caves, Eleanor M. |
collection | PubMed |
description | Among fishes in the family Poeciliidae, signals such as colour patterns, ornaments and courtship displays play important roles in mate choice and male–male competition. Despite this, visual capabilities in poeciliids are understudied, in particular, visual acuity, the ability to resolve detail. We used three methods to quantify visual acuity in male and female green swordtails (Xiphophorus helleri), a species in which body size and the length of the male's extended caudal fin (‘sword’) serve as assessment signals during mate choice and agonistic encounters. Topographic distribution of retinal ganglion cells (RGCs) was similar in all individuals and was characterized by areas of high cell densities located centro-temporally and nasally, as well as a weak horizontal streak. Based on the peak density of RGCs in the centro-temporal area, anatomical acuity was estimated to be approximately 3 cycles per degree (cpd) in both sexes. However, a behavioural optomotor assay found significantly lower mean acuity in males (0.8 cpd) than females (3.0 cpd), which was not explained by differences in eye size between males and females. An additional behavioural assay, in which we trained individuals to discriminate striped gratings from grey stimuli of the same mean luminance, also showed lower acuity in males (1–2 cpd) than females (2–3 cpd). Thus, although retinal anatomy predicts identical acuity in males and females, two behavioural assays found higher acuity in females than males, a sexual dimorphism that is rare outside of invertebrates. Overall, our results have implications for understanding how poeciliids perceive visual signals during mate choice and agonistic encounters. |
format | Online Article Text |
id | pubmed-8729911 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2021 |
publisher | The Company of Biologists Ltd |
record_format | MEDLINE/PubMed |
spelling | pubmed-87299112022-01-12 Sex differences in behavioural and anatomical estimates of visual acuity in the green swordtail, Xiphophorus helleri Caves, Eleanor M. de Busserolles, Fanny Kelley, Laura A. J Exp Biol Research Article Among fishes in the family Poeciliidae, signals such as colour patterns, ornaments and courtship displays play important roles in mate choice and male–male competition. Despite this, visual capabilities in poeciliids are understudied, in particular, visual acuity, the ability to resolve detail. We used three methods to quantify visual acuity in male and female green swordtails (Xiphophorus helleri), a species in which body size and the length of the male's extended caudal fin (‘sword’) serve as assessment signals during mate choice and agonistic encounters. Topographic distribution of retinal ganglion cells (RGCs) was similar in all individuals and was characterized by areas of high cell densities located centro-temporally and nasally, as well as a weak horizontal streak. Based on the peak density of RGCs in the centro-temporal area, anatomical acuity was estimated to be approximately 3 cycles per degree (cpd) in both sexes. However, a behavioural optomotor assay found significantly lower mean acuity in males (0.8 cpd) than females (3.0 cpd), which was not explained by differences in eye size between males and females. An additional behavioural assay, in which we trained individuals to discriminate striped gratings from grey stimuli of the same mean luminance, also showed lower acuity in males (1–2 cpd) than females (2–3 cpd). Thus, although retinal anatomy predicts identical acuity in males and females, two behavioural assays found higher acuity in females than males, a sexual dimorphism that is rare outside of invertebrates. Overall, our results have implications for understanding how poeciliids perceive visual signals during mate choice and agonistic encounters. The Company of Biologists Ltd 2021-12-17 /pmc/articles/PMC8729911/ /pubmed/34787303 http://dx.doi.org/10.1242/jeb.243420 Text en © 2021. Published by The Company of Biologists Ltd https://creativecommons.org/licenses/by/4.0/This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution and reproduction in any medium provided that the original work is properly attributed. |
spellingShingle | Research Article Caves, Eleanor M. de Busserolles, Fanny Kelley, Laura A. Sex differences in behavioural and anatomical estimates of visual acuity in the green swordtail, Xiphophorus helleri |
title | Sex differences in behavioural and anatomical estimates of visual acuity in the green swordtail, Xiphophorus helleri |
title_full | Sex differences in behavioural and anatomical estimates of visual acuity in the green swordtail, Xiphophorus helleri |
title_fullStr | Sex differences in behavioural and anatomical estimates of visual acuity in the green swordtail, Xiphophorus helleri |
title_full_unstemmed | Sex differences in behavioural and anatomical estimates of visual acuity in the green swordtail, Xiphophorus helleri |
title_short | Sex differences in behavioural and anatomical estimates of visual acuity in the green swordtail, Xiphophorus helleri |
title_sort | sex differences in behavioural and anatomical estimates of visual acuity in the green swordtail, xiphophorus helleri |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8729911/ https://www.ncbi.nlm.nih.gov/pubmed/34787303 http://dx.doi.org/10.1242/jeb.243420 |
work_keys_str_mv | AT caveseleanorm sexdifferencesinbehaviouralandanatomicalestimatesofvisualacuityinthegreenswordtailxiphophorushelleri AT debusserollesfanny sexdifferencesinbehaviouralandanatomicalestimatesofvisualacuityinthegreenswordtailxiphophorushelleri AT kelleylauraa sexdifferencesinbehaviouralandanatomicalestimatesofvisualacuityinthegreenswordtailxiphophorushelleri |