Testing multiple hypotheses on the colour change of treefrogs in response to various external conditions

Abstract Amphibians are famous for their ability to change colours. And a considerable number of studies have investigated the internal and external factors that affect the expression of this phenotypic plasticity. Evidence to date suggests that thermoregulation and camouflage are the main pressures...

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Main Authors: Chohee Park, Seongsoo No, Sohee Yoo, Dogeun Oh, Yerin Hwang, Yongsu Kim, Changku Kang
Format: Article
Language:English
Published: Nature Portfolio 2023-03-01
Series:Scientific Reports
Online Access:https://doi.org/10.1038/s41598-023-31262-y
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author Chohee Park
Seongsoo No
Sohee Yoo
Dogeun Oh
Yerin Hwang
Yongsu Kim
Changku Kang
author_facet Chohee Park
Seongsoo No
Sohee Yoo
Dogeun Oh
Yerin Hwang
Yongsu Kim
Changku Kang
author_sort Chohee Park
collection DOAJ
description Abstract Amphibians are famous for their ability to change colours. And a considerable number of studies have investigated the internal and external factors that affect the expression of this phenotypic plasticity. Evidence to date suggests that thermoregulation and camouflage are the main pressures that influence frogs’ adaptive colour change responses. However, certain gaps in our knowledge of this phenomenon remain, namely: (i) how do frogs adjust their colour in response to continuously changing external conditions?; (ii) what is the direction of change when two different functions of colour (camouflage and thermoregulation) are in conflict?; (iii) does reflectance in the near-infrared region show thermally adaptive change?; and (iv) is the colour change ability of each frog an individual trait (i.e., consistent within an individual over time)? Using Dryophytes japonicus (Hylidae, Hyla), we performed a series of experiments to answer the above questions. We first showed that frogs’ responses to continuously-changing external conditions (i.e., background colour and temperature) were not linear and limited to the range they experience under natural conditions. Second, when a functional conflict existed, camouflage constrained the adaptive response for thermoregulation and vice versa. Third, though both temperature and background colour induced a change in near-infrared reflectance, this change was largely explained by the high correlation between colour (reflectance in the visible spectrum) and near-infrared reflectance. Fourth, within-individual variation in colour change capacity (i.e., the degree of colour change an individual can display) was lower than inter-individual variation, suggesting individuality of colour change capacity; however, we also found that colour change capacity could change gradually with time within individuals. Our results collectively reveal several new aspects of how evolution shapes the colour change process and highlight how variation in external conditions restricts the extent of colour change in treefrogs.
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spelling doaj.art-e47c56b3ed1547a28e72aaf36a78f2582023-03-22T10:54:08ZengNature PortfolioScientific Reports2045-23222023-03-011311910.1038/s41598-023-31262-yTesting multiple hypotheses on the colour change of treefrogs in response to various external conditionsChohee Park0Seongsoo No1Sohee Yoo2Dogeun Oh3Yerin Hwang4Yongsu Kim5Changku Kang6Department of Biosciences, Mokpo National UniversityDepartment of Biosciences, Mokpo National UniversityDepartment of Biosciences, Mokpo National UniversityDepartment of Biosciences, Mokpo National UniversityDepartment of Biosciences, Mokpo National UniversityDepartment of Agricultural Biotechnology, Seoul National UniversityDepartment of Agricultural Biotechnology, Seoul National UniversityAbstract Amphibians are famous for their ability to change colours. And a considerable number of studies have investigated the internal and external factors that affect the expression of this phenotypic plasticity. Evidence to date suggests that thermoregulation and camouflage are the main pressures that influence frogs’ adaptive colour change responses. However, certain gaps in our knowledge of this phenomenon remain, namely: (i) how do frogs adjust their colour in response to continuously changing external conditions?; (ii) what is the direction of change when two different functions of colour (camouflage and thermoregulation) are in conflict?; (iii) does reflectance in the near-infrared region show thermally adaptive change?; and (iv) is the colour change ability of each frog an individual trait (i.e., consistent within an individual over time)? Using Dryophytes japonicus (Hylidae, Hyla), we performed a series of experiments to answer the above questions. We first showed that frogs’ responses to continuously-changing external conditions (i.e., background colour and temperature) were not linear and limited to the range they experience under natural conditions. Second, when a functional conflict existed, camouflage constrained the adaptive response for thermoregulation and vice versa. Third, though both temperature and background colour induced a change in near-infrared reflectance, this change was largely explained by the high correlation between colour (reflectance in the visible spectrum) and near-infrared reflectance. Fourth, within-individual variation in colour change capacity (i.e., the degree of colour change an individual can display) was lower than inter-individual variation, suggesting individuality of colour change capacity; however, we also found that colour change capacity could change gradually with time within individuals. Our results collectively reveal several new aspects of how evolution shapes the colour change process and highlight how variation in external conditions restricts the extent of colour change in treefrogs.https://doi.org/10.1038/s41598-023-31262-y
spellingShingle Chohee Park
Seongsoo No
Sohee Yoo
Dogeun Oh
Yerin Hwang
Yongsu Kim
Changku Kang
Testing multiple hypotheses on the colour change of treefrogs in response to various external conditions
Scientific Reports
title Testing multiple hypotheses on the colour change of treefrogs in response to various external conditions
title_full Testing multiple hypotheses on the colour change of treefrogs in response to various external conditions
title_fullStr Testing multiple hypotheses on the colour change of treefrogs in response to various external conditions
title_full_unstemmed Testing multiple hypotheses on the colour change of treefrogs in response to various external conditions
title_short Testing multiple hypotheses on the colour change of treefrogs in response to various external conditions
title_sort testing multiple hypotheses on the colour change of treefrogs in response to various external conditions
url https://doi.org/10.1038/s41598-023-31262-y
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