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Giovanetti L, Casini S, Campani T, Caliani I. State of the art, gaps and future perspectives on common kestrel ecotoxicology. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2023; 102:104237. [PMID: 37481048 DOI: 10.1016/j.etap.2023.104237] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 07/17/2023] [Accepted: 07/19/2023] [Indexed: 07/24/2023]
Abstract
Anthropogenic activities have caused a steady decline of common kestrel (Falco tinnunculus) since the 1980 s. Effects, especially sublethal effects of contaminants, need to be investigated to ensure the conservation of this species. Data about countries, biological material, contaminants classes, and methodological approaches were collected from scientific publications to highlight gaps on common kestrel toxicology and ecotoxicology. We found that most studies have been conducted in Europe and in the field, underlining a lack of in vitro studies. The studies investigated mainly contaminant levels, while sublethal effects, evaluation of emerging contaminants and use of non-invasive or low-invasive samples were scarce. This work shows important gaps on toxicological status of the common kestrel, highlighting the importance of developing a non-lethal approach that combines responses at different levels of biological organization, as well as data on chemical contamination and on the environment in which the different populations inhabit.
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Affiliation(s)
- Laura Giovanetti
- Department of Physics, Earth and Environmental Sciences, University of Siena, via Mattioli, 4, 53100, Siena, Italy
| | - Silvia Casini
- Department of Physics, Earth and Environmental Sciences, University of Siena, via Mattioli, 4, 53100, Siena, Italy.
| | - Tommaso Campani
- Department of Physics, Earth and Environmental Sciences, University of Siena, via Mattioli, 4, 53100, Siena, Italy
| | - Ilaria Caliani
- Department of Physics, Earth and Environmental Sciences, University of Siena, via Mattioli, 4, 53100, Siena, Italy
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2
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Mizuno A, Soma M. Star finches Neochmia ruficauda have a visual preference for white dot patterns: a possible case of trypophilia. Anim Cogn 2022; 25:1271-1279. [PMID: 35294684 PMCID: PMC9617841 DOI: 10.1007/s10071-022-01609-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 12/03/2021] [Accepted: 03/01/2022] [Indexed: 11/25/2022]
Abstract
Many animals have polka dot patterns on their body surface, some of which are known to have signalling functions; however, their evolutionary origins remain unclear. Dot patterns can trigger a fear response (trypophobia) in humans and are known to function as aposematic signals in non-human animals, suggesting that dots may deserve attention for biological reasons. Interestingly in many birds, plumage dot patterns serve for social/sexual signalling. To understand their evolution, we have focused on the sensory bias hypothesis, which predicts the role of pre-existing sensory preference driven by natural selection in shaping signal design. Our previous phylogenetic comparative study supported the hypothesis and showed that diet-driven visual preference promoted the evolution of plumage patterns, as there was an evolutionary correlation between termite-eating (white roundish gregarious prey) and the presence of plumage dot patterns in species of the family Estrildidae. This suggests that these species possess an intrinsic preference for dots. To test this, we compared the responses of an Estrildid species with dot plumage pattern (star finch Neochmia ruficauda) towards simultaneously presented monochrome-printed white dot vs white stripe patterns under both food-deprived and -supplied conditions. Overall, star finches preferred dots to stripes. They showed foraging-like behaviours almost only toward dots when hungry and gazed at dots frequently even when food was available, suggesting both hunger-related and hunger-neutral dot preferences. These results are rather surprising, given how strongly the subjects were attracted to abstract dot patterns without organic structure, but provided good support for the sensory bias hypothesis.
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Affiliation(s)
- Ayumi Mizuno
- Biosystems Science Course, The Graduate School of Life Science, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Masayo Soma
- Department of Biology, Faculty of Science, Hokkaido University, Kita 10 Nishi 8, Kita-ku, Sapporo, Hokkaido, 060-0810, Japan.
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3
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Zúñiga-Vega JJ, Pruett JA, Ossip-Drahos AG, Campos SM, Seddon RJ, Price SL, Romero-Diaz C, Rivera JA, Vital-García C, Hews DK, Martins EP. Information out of the blue: phenotypic correlates of abdominal color patches in Sceloporus lizards. ZOOLOGY 2021; 149:125961. [PMID: 34592493 DOI: 10.1016/j.zool.2021.125961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 08/12/2021] [Accepted: 08/19/2021] [Indexed: 11/28/2022]
Abstract
Colorful ornaments are important visual signals for animal communication that can provide critical information about the quality of the signaler. In this study, we focused on different color characteristics of the abdominal patches of males of six lizard species from the genus Sceloporus. We addressed three main objectives. First, we examined if size, brightness, saturation, and conspicuousness of these ornaments are indicative of body size, condition, immune function, or levels of testosterone and corticosterone. Second, we evaluated if the distinct components of these abdominal patches (blue or green patches and black stripes) transmit similar information about the signaler, which would support the redundant signal hypothesis, or if these components are related to different phenotypic traits, which would support the multiple message hypothesis. Third, we compared the phenotypic correlates of these ornaments among our six species to understand the degree of conservatism in the signaling patterns or to find species-specific signals. Using data collected from males in natural conditions and a multi-model inference framework, we found that in most species the area of the patches and the brightness of the blue component are positively related to body size. Thus, these color characteristics are presumably indicative of the physical strength and competitive ability of males and these shared signals were likely inherited from a common ancestor. In half of the species, males in good body condition also exhibit relatively larger blue and black areas, suggesting that the expression of these ornaments is condition-dependent. Abdominal patches also provide information about immunocompetence of the males as indicated by different correlations between certain color characteristics and ectoparasite load, counts of heterophils, and the heterophil:lymphocyte ratio. Our findings reveal that area and brightness of the abdominal patches signal the size and body condition of males, whereas blue saturation and conspicuousness with respect to the surrounding substrate are indicative of immune condition, thus supporting the multiple message hypothesis. However, some of these correlations were not shared by all species and, hence, point to intriguing species-specific signals.
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Affiliation(s)
- J Jaime Zúñiga-Vega
- Departamento de Ecología y Recursos Naturales, Facultad de Ciencias, Universidad Nacional Autónoma de México, Circuito Exterior s/n, Ciudad Universitaria, Coyoacán, Mexico City, 04510, Mexico.
| | - Jake A Pruett
- Department of Biology, Indiana State University, Science Building Room 283, 600 North Chestnut Street, Terre Haute, IN 47809, USA; Department of Biological Sciences, Southeastern Oklahoma State University, 425 W. University Boulevard, Durant, OK 74701, USA.
| | - Alison G Ossip-Drahos
- Department of Chemistry and Physical Sciences, Marian University, 3200 Cold Springs Road, Indianapolis, IN 46222, USA.
| | - Stephanie M Campos
- Biology Department, Swarthmore College, 500 College Avenue, Swarthmore, PA 19081, USA.
| | - Ryan J Seddon
- Department of Biology, Indiana State University, Science Building Room 283, 600 North Chestnut Street, Terre Haute, IN 47809, USA; Center for Global Communication Strategies, University of Tokyo, 3-8-4 Komaba, Meguro-ku, Tokyo, 153-8902, Japan.
| | - Savannah L Price
- Department of Biology, Indiana State University, Science Building Room 283, 600 North Chestnut Street, Terre Haute, IN 47809, USA.
| | - Cristina Romero-Diaz
- School of Life Sciences, Arizona State University, 427 East Tyler Mall, Tempe, AZ 85287, USA.
| | - Julio A Rivera
- School of Life Sciences, Arizona State University, 427 East Tyler Mall, Tempe, AZ 85287, USA.
| | - Cuauhcihuatl Vital-García
- Departamento de Ciencias Veterinarias, Universidad Autónoma de Ciudad Juárez, Anillo Envolvente y Estocolmo s/n, Colonia Progresista, Ciudad Juárez, Chihuahua, 32310, Mexico.
| | - Diana K Hews
- Department of Biology, Indiana State University, Science Building Room 283, 600 North Chestnut Street, Terre Haute, IN 47809, USA.
| | - Emília P Martins
- School of Life Sciences, Arizona State University, 427 East Tyler Mall, Tempe, AZ 85287, USA.
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4
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Nolazco S, Hall ML, Kingma SA, Delhey K, Peters A. No evidence for an adaptive role of early molt into breeding plumage in a female fairy wren. Behav Ecol 2019. [DOI: 10.1093/beheco/arz203] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Abstract
The evolution of ornaments as sexually selected signals is well understood in males, but female ornamentation remains understudied. Fairy wrens offer an excellent model system, given their complex social structure and mating systems, and the diversity of female ornamentation. We investigated whether early molt into ornamental breeding plumage plays an adaptive role in females of the monogamous purple-crowned fairy wren Malurus coronatus, the only fairy wren known to have female seasonal plumage. Using 6 years of monitoring, we found that the timing of female molt was similar to males, but there was no evidence for assortative mating. Like males (previous study), older and dominant individuals acquired their breeding plumage earlier; however, in contrast to males, early molt did not seem to be costly since unfavorable environmental conditions or previous reproductive effort did not delay molt. Early female molt was not associated with any indicator of reproductive quality nor did it attract additional offspring care by their partners. We also found no association between early molt and the likelihood of acquiring a dominant (breeding) position or with the presence or proximity to same-sex rivals. Our study results, which are similar to previous findings in conspecific males, suggest that directional selection for early molt might be relaxed in this species, in contrast to other genetically polygamous fairy wrens in which early molt predicts extrapair mating success in males. However, the finding that molt timing is status dependent raises the possibility that other attributes of the ornament may fulfill an adaptive function in females.
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Affiliation(s)
- Sergio Nolazco
- School of Biological Sciences, Monash University, Clayton, Victoria, Australia
| | - Michelle L Hall
- School of BioSciences, University of Melbourne, Parkville, Australia
- Max Planck Institute for Ornithology, Vogelwarte Radolfzell, Radolfzell, Germany
- School of Biological Sciences, University of Western Australia, Perth, Western Australia, Australia
| | - Sjouke A Kingma
- Max Planck Institute for Ornithology, Vogelwarte Radolfzell, Radolfzell, Germany
- Behavioural Ecology Group, Department of Animal Sciences, Wageningen University and Research, WD Wageningen, The Netherlands
| | - Kaspar Delhey
- School of Biological Sciences, Monash University, Clayton, Victoria, Australia
- Max Planck Institute for Ornithology, Vogelwarte Radolfzell, Radolfzell, Germany
| | - Anne Peters
- School of Biological Sciences, Monash University, Clayton, Victoria, Australia
- Max Planck Institute for Ornithology, Vogelwarte Radolfzell, Radolfzell, Germany
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5
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Johnson AM, Chang CH, Fuller RC. Testing the potential mechanisms for the maintenance of a genetic color polymorphism in bluefin killifish populations. Curr Zool 2018; 64:733-743. [PMID: 30538733 PMCID: PMC6280095 DOI: 10.1093/cz/zoy017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 02/28/2018] [Indexed: 02/03/2023] Open
Abstract
The maintenance of genetic variation in the face of natural selection is a long-standing question in evolutionary biology. In the bluefin killifish Lucania goodei, male coloration is polymorphic. Males can produce either red or yellow coloration in their anal fins, and both color morphs are present in all springs. These 2 morphs are heritable and how they are maintained in nature is unknown. Here, we tested 2 mechanisms for the maintenance of the red/yellow color morphs. Negative frequency-dependent mating success predicts that rare males have a mating advantage over common males. Spatial variation in fitness predicts that different color morphs have an advantage in different microhabitat types. Using a breeding experiment, we tested these hypotheses by creating populations with different ratios of red to yellow males (5 red:1 yellow; 1 red:5 yellow) and determining male mating success on shallow and deep spawning substrates. We found no evidence of negative frequency-dependent mating success. Common morphs tended to have higher mating success, and this was particularly so on shallow spawning substrates. However, on deep substrates, red males enjoyed higher mating success than yellow males, particularly so when red males were rare. However, yellow males did not have an advantage at either depth nor when rare. We suggest that preference for red males is expressed in deeper water, possibly due to alterations in the lighting environment. Finally, male pigment levels were correlated with one another and predicted male mating success. Hence, pigmentation plays an important role in male mating success.
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Affiliation(s)
- Ashley M Johnson
- Department of Animal Biology, School of Integrative Biology, University of Illinois at Urbana-Champaign, Champaign, IL, USA
| | - Chia-Hao Chang
- Department of Animal Biology, School of Integrative Biology, University of Illinois at Urbana-Champaign, Champaign, IL, USA
| | - Rebecca C Fuller
- Department of Animal Biology, School of Integrative Biology, University of Illinois at Urbana-Champaign, Champaign, IL, USA
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6
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Arai E, Hasegawa M, Makino T, Hagino A, Sakai Y, Ohtsuki H, Wakamatsu K, Kawata M. Physiological conditions and genetic controls of phaeomelanin pigmentation in nestling barn swallows. Behav Ecol 2017. [DOI: 10.1093/beheco/arx012] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
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7
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Järvistö PE, Calhim S, Schuett W, Sirkiä PM, Velmala W, Laaksonen T. Carry-over effects of conditions at the wintering grounds on breeding plumage signals in a migratory bird: roles of phenotypic plasticity and selection. J Evol Biol 2016; 29:1569-84. [PMID: 27159261 DOI: 10.1111/jeb.12892] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 04/25/2016] [Accepted: 05/04/2016] [Indexed: 02/05/2023]
Abstract
To understand the consequences of ever-changing environment on the dynamics of phenotypic traits, distinguishing between selection processes and individual plasticity is crucial. We examined individual consistency/plasticity in several male secondary sexual traits expressed during the breeding season (white wing and forehead patch size, UV reflectance of white wing patch and dorsal melanin coloration) in a migratory pied flycatcher (Ficedula hypoleuca) population over an 11-year period. Furthermore, we studied carry-over effects of three environmental variables (NAO, a climatic index; NDVI, a vegetation index; and rainfall) at the wintering grounds (during prebreeding moult) on the expression of these breeding plumage traits of pied flycatcher males at individual and population levels. Whereas NAO correlates negatively with moisture in West Africa, NDVI correlates positively with primary production. Forehead patch size and melanin coloration were highly consistent within individuals among years, whereas the consistency of the other two traits was moderate. Wing patch size decreased with higher NAO and increased with higher rainfall and NDVI at the individual level. Interestingly, small-patched males suffered lower survival during high NAO winters than large-patched males, and vice versa during low NAO winters. These counteracting processes meant that the individual-level change was masked at the population level where no relationship was found. Our results provide a good example of how variation in the phenotypic composition of a natural population can be a result of both environment-dependent individual plasticity and short-term microevolution. Moreover, when plasticity and viability selection operate simultaneously, their impacts on population composition may not be evident.
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Affiliation(s)
- P E Järvistö
- Section of Ecology, Department of Biology, University of Turku, Turku, Finland
| | - S Calhim
- Section of Ecology and Evolutionary Biology, Department of Biology and Environmental Sciences, University of Jyväskylä, Jyväskylä, Finland
| | - W Schuett
- Zoological Institute, University of Hamburg, Hamburg, Germany
| | - P M Sirkiä
- Section of Ecology, Department of Biology, University of Turku, Turku, Finland.,Finnish Museum of Natural History, Zoology Unit, University of Helsinki, Helsinki, Finland
| | - W Velmala
- Section of Ecology, Department of Biology, University of Turku, Turku, Finland
| | - T Laaksonen
- Section of Ecology, Department of Biology, University of Turku, Turku, Finland
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8
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Roulin A. Condition-dependence, pleiotropy and the handicap principle of sexual selection in melanin-based colouration. Biol Rev Camb Philos Soc 2015; 91:328-48. [PMID: 25631160 DOI: 10.1111/brv.12171] [Citation(s) in RCA: 99] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Revised: 11/30/2014] [Accepted: 12/11/2014] [Indexed: 02/03/2023]
Abstract
The signalling function of melanin-based colouration is debated. Sexual selection theory states that ornaments should be costly to produce, maintain, wear or display to signal quality honestly to potential mates or competitors. An increasing number of studies supports the hypothesis that the degree of melanism covaries with aspects of body condition (e.g. body mass or immunity), which has contributed to change the initial perception that melanin-based colour ornaments entail no costs. Indeed, the expression of many (but not all) melanin-based colour traits is weakly sensitive to the environment but strongly heritable suggesting that these colour traits are relatively cheap to produce and maintain, thus raising the question of how such colour traits could signal quality honestly. Here I review the production, maintenance and wearing/displaying costs that can generate a correlation between melanin-based colouration and body condition, and consider other evolutionary mechanisms that can also lead to covariation between colour and body condition. Because genes controlling melanic traits can affect numerous phenotypic traits, pleiotropy could also explain a linkage between body condition and colouration. Pleiotropy may result in differently coloured individuals signalling different aspects of quality that are maintained by frequency-dependent selection or local adaptation. Colouration may therefore not signal absolute quality to potential mates or competitors (e.g. dark males may not achieve a higher fitness than pale males); otherwise genetic variation would be rapidly depleted by directional selection. As a consequence, selection on heritable melanin-based colouration may not always be directional, but mate choice may be conditional to environmental conditions (i.e. context-dependent sexual selection). Despite the interest of evolutionary biologists in the adaptive value of melanin-based colouration, its actual role in sexual selection is still poorly understood.
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Affiliation(s)
- Alexandre Roulin
- Department of Ecology and Evolution, University of Lausanne, Building Biophore, 1015 Lausanne, Switzerland
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D'Alba L, Van Hemert C, Spencer KA, Heidinger BJ, Gill L, Evans NP, Monaghan P, Handel CM, Shawkey MD. Melanin-Based Color of Plumage: Role of Condition and of Feathers' Microstructure. Integr Comp Biol 2014; 54:633-44. [DOI: 10.1093/icb/icu094] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
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10
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Dubey S, Roulin A. Evolutionary and biomedical consequences of internal melanins. Pigment Cell Melanoma Res 2014; 27:327-38. [DOI: 10.1111/pcmr.12231] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Sylvain Dubey
- Department of Ecology and Evolution; University of Lausanne; Biophore Lausanne Switzerland
| | - Alexandre Roulin
- Department of Ecology and Evolution; University of Lausanne; Biophore Lausanne Switzerland
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Integrated plumage colour variation in relation to body condition, reproductive investment and laying date in the collared flycatcher. Naturwissenschaften 2013; 100:983-91. [DOI: 10.1007/s00114-013-1099-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Revised: 08/30/2013] [Accepted: 09/02/2013] [Indexed: 10/26/2022]
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12
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Roulin A, Mangels J, Wakamatsu K, Bachmann T. Sexually dimorphic melanin-based colour polymorphism, feather melanin content, and wing feather structure in the barn owl (Tyto alba). Biol J Linn Soc Lond 2013. [DOI: 10.1111/bij.12078] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Alexandre Roulin
- Department of Ecology and Evolution; Université de Lausanne; Lausanne; Switzerland
| | - Jule Mangels
- Institute for Fluid Mechanics and Aerodynamics; Technische Universität Darmstadt; Darmstadt; Germany
| | - Kazumasa Wakamatsu
- Department of Chemistry; School of Health Sciences; Fujita Health University; Toyoake; Aichi; Japan
| | - Thomas Bachmann
- Institute for Fluid Mechanics and Aerodynamics; Technische Universität Darmstadt; Darmstadt; Germany
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13
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Viability is associated with melanin-based coloration in the barn swallow (Hirundo rustica). PLoS One 2013; 8:e60426. [PMID: 23573254 PMCID: PMC3616026 DOI: 10.1371/journal.pone.0060426] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2013] [Accepted: 02/26/2013] [Indexed: 01/13/2023] Open
Abstract
Pigmentation of body surface in animals can have multiple determinants and accomplish diverse functions. Eumelanin and pheomelanin are the main animal pigments, being responsible of yellow, brownish-red and black hues, and have partly common biosynthetic pathways. Many populations of vertebrates show individual variation in melanism, putatively with large heritable component. Genes responsible for eu- or pheomelanogenesis have pleiotropic but contrasting effects on life-history traits, explaining the patterns of covariation observed between melanization and physiology (e.g. immunity and stress response), sexual behavior and other characters in diverse taxa. Yet, very few studies in the wild have investigated if eu- and pheomelanization predict major fitness traits like viability or fecundity. In this correlative study, by contrasting adult barn swallows (Hirundo rustica) matched for age, sex, breeding site, and year and date of sampling, we show that males but not females that survived until the next year had paler, relatively more eu- than pheomelanic pigmentation of ventral body feathers. Better performance of individuals that allocate relatively more to eumelanogenesis was expected based on previous evidence on covariation between eumelanic pigmentation and specific traits related to immunity and susceptibility to stress. However, together with the evidence of no covariation between viability and melanization among females, this finding raises the question of the mechanisms that maintain variation in genes for melanogenesis. We discuss the possibility that eu- and pheomelanization are under contrasting viability and sexual selection, as suggested by larger breeding and sperm competition success of darker males from other barn swallow subspecies.
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Field DJ, D'Alba L, Vinther J, Webb SM, Gearty W, Shawkey MD. Melanin concentration gradients in modern and fossil feathers. PLoS One 2013; 8:e59451. [PMID: 23555675 PMCID: PMC3608712 DOI: 10.1371/journal.pone.0059451] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Accepted: 02/14/2013] [Indexed: 11/18/2022] Open
Abstract
In birds and feathered non-avian dinosaurs, within-feather pigmentation patterns range from discrete spots and stripes to more subtle patterns, but the latter remain largely unstudied. A ∼55 million year old fossil contour feather with a dark distal tip grading into a lighter base was recovered from the Fur Formation in Denmark. SEM and synchrotron-based trace metal mapping confirmed that this gradient was caused by differential concentration of melanin. To assess the potential ecological and phylogenetic prevalence of this pattern, we evaluated 321 modern samples from 18 orders within Aves. We observed that the pattern was found most frequently in distantly related groups that share aquatic ecologies (e.g. waterfowl Anseriformes, penguins Sphenisciformes), suggesting a potential adaptive function with ancient origins.
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Affiliation(s)
- Daniel J Field
- Department of Geology and Geophysics, Yale University, New Haven, Connecticut, United States of America.
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15
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Rodgers GM, Gladman N, Corless H, Morrell L. Costs of colour change in fish: food intake and behavioural decisions. J Exp Biol 2013; 216:2760-7. [DOI: 10.1242/jeb.080879] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Summary
Many animals, particularly reptiles, amphibians, fish and cephalopods, have the ability to change their body colour, for functions including thermoregulation, signalling and predator avoidance. Many fish plastically darken their body colouration in response to dark visual backgrounds, and this functions to reduce predation risk. Here, we test the hypotheses that 1) colour change in fish carries with it an energetic cost and 2) affects subsequent shoal and habitat choice decisions. We demonstrate that guppies (Poecilia reticulata) change colour in response to dark and light visual backgrounds, and that doing so carries an energetic cost in terms of food consumption. By increasing food intake, however, guppies are able to maintain growth rates and meet the energetic costs of changing colour. Following colour change, fish preferentially chose habitats and shoals that match their own body colouration, and maximise crypsis, thus avoiding the need for further colour change, but also potentially paying an opportunity cost associated with restriction to particular habitats and social associates. Thus, colour change to match the background is complemented by behavioural strategies, which should act to maximise fitness in variable environments.
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