Melanin- versus carotenoid-based sexual signals: is the difference really so black and red?

Griffith, Simon C.; Parker, Timothy; Olson, Valérie A.

doi:10.1016/j.anbehav.2005.07.016

Cited by 226 publications

(223 citation statements)

References 96 publications

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“…The proximate and ultimate causes for the association between eumelanin-based ornamentation and other fitness-related traits such as immunocompetence remains debated (see e.g. Roulin 2004b; Griffith et al 2006). The fact that glucocorticoid suppression of immune function has been observed throughout various vertebrate taxa (McEwen et al 1997;Weyts et al 1999) provide a likely proximate link between eumelanin colouration and disease resistance which so far has received little attention.…”

Section: Discussionmentioning

confidence: 99%

Melanin-based skin spots reflect stress responsiveness in salmonid fish

Kittilsen

Schjolden

Beitnes-Johansen

et al. 2009

Hormones and Behavior

128

122

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This version available http://nora.nerc.ac.uk/7671/ NERC has developed NORA to enable users to access research outputs wholly or partially funded by NERC. Copyright and other rights for material on this site are retained by the authors and/or other rights owners. Users should read the terms and conditions of use of this material at http://nora.nerc.ac.uk/policies.html#access This document is the author's final manuscript version of the journal article, incorporating any revisions agreed during the peer review process. Some differences between this and the publisher's version remain. You are advised to consult the publisher's version if you wish to cite from this article. www.elsevier.comContact CEH NORA team at nora@ceh.ac.ukThe NERC and CEH trade marks and logos ('the Trademarks') are registered trademarks of NERC in the UK and other countries, and may not be used without the prior written consent of the Trademark owner. Wilson et al. 1994;Réale et al. 2007). Notwithstanding a certain lack of consensus in terminology, the evolution of these analogues of human personality has evoked considerable scientific interest. Among the questions raised are by which mechanisms behavioural syndromes are inherited, how the variation is maintained, which circumstances benefit different complex phenotypes, and what are the costs and benefits of limited plasticity imposed by more or less fixed trait associations (DeWitt et al. 1998;Koolhaas et al. 1999;Sih et al. 2004; Dingemanse and Réale 2005;McElreath et al. 2007;Réale et al. 2007;Wolf et al. 2007). Furthermore, in the barn owl (Tyto Alba) melanin-based colouration is associated with several behavioural, morphological and physiological characteristics that have been linked to stress coping ability (Almasi et al. 2008).Based on observations that HR and LR trout differed in melanin pigmentation our hypothesis was that spotted fish, in the closely related specie Atlantic salmon (Salmo Salar), 5 would show a lower cortisol reponse to stress when compared to a non-spotted group of individuals. Furthermore, several documented changes in the behaviour of the two trout lines made us predict that also behaviour would differ between groups of spotted and non-spotted fish. The main focus of this study was therefore to test the hypothesis that there exist an association between melanin-based pigmentation and hypothalamus-pituitary-interrenal (HPIaxis) reactivity in salmonid fish. Furthermore, we tested the prediction that behavioural differences are present in two groups of fish chosen divergently on melanin pigmentation. Materials and methods Quantification of melanin-based colorationIn the studies described below, photographs of experimental fish were captured with a Canon EOS 450D digital camera and transferred to a computer for further analyses of melanin-based coloration. Prior to photography, each fish were sedated in 200 mg/l MS-222 and placed adjacent to a measuring tape with millimetre resolution, allowing for an accurate estimation of the area where spots were counted. The d...

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Section: Discussionmentioning

confidence: 99%

Melanin-based skin spots reflect stress responsiveness in salmonid fish

Kittilsen

Schjolden

Beitnes-Johansen

et al. 2009

Hormones and Behavior

128

122

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“…There has been considerable speculation on potential mechanisms linking intraspecific signalling ornaments to internal or external states [19,31]. Given the importance of the stress response in transducing emergency events into physiological responses, and the central role CORT plays in those responses [1], it is not surprising that studies have examined CORT as a potential physiological mechanism regulating signalling ornaments [32].…”

Section: Rsblroyalsocietypublishingorg Biol Lett 9: 20130440mentioning

confidence: 99%

“…Similar to other melanin-based ornaments [19], the black 'bib' of male house sparrows (Passer domesticus) is an important intraspecific signal. Bib size positively correlates with fighting ability, age and body condition [20] as well as with stressinduced concentrations of CORT during breeding [21].…”

Section: Introductionmentioning

confidence: 99%

The size of a melanin-based plumage ornament correlates with glucocorticoid receptor concentrations in the skin of that ornament

Lattin

Romero

2013

Biol. Lett.

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PhysiologyThe size of a melanin-based plumage ornament correlates with glucocorticoid receptor concentrations in the skin of that ornament Christine R. Lattin and L. Michael Romero Department of Biology, Tufts University, Medford, MA 02155, USA Glucocorticoid hormones such as corticosterone (CORT) play crucial roles in many physiological processes. CORT's actions are primarily mediated via binding to two receptors (glucocorticoid receptors (GRs) and mineralocorticoid receptors (MRs)) in different target tissues. CORT receptors can be independently regulated from circulating hormone titres, from tissue to tissue and even within different regions of the same tissue type. Increasing evidence has shown relationships between circulating CORT and melaninbased pigmentation in skin and feathers, yet to our knowledge, there have been no studies of CORT receptors in the skin of melanized ornaments. Male house sparrows (Passer domesticus) have a black, melanized bib, and evidence suggests that bib size is an important intraspecific signal. We examined the relationship between bib area and tissue sensitivity to CORT by quantifying GR and MR in bib skin and in adjacent paler-feathered belly skin (as a control tissue) at different life-history stages using radioligand binding assays. Males with larger bibs relative to their life-history stage had less GR in bib skin, but not belly skin, than males with smaller bibs. These results suggest a connection between the size of a melanin-based ornament and the underlying tissue's responsiveness to CORT.

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“…In spite of strong support for genetic control in melanin production, melanin-based traits are frequently related to the condition of the bearer, which often fluctuates with environmental conditions (reviewed in Griffith et al 2006;McGraw 2008). But what kind of environmental factors might influence the expression of these traits?…”

Section: Introductionmentioning

confidence: 99%

“…they may not be limited resources; e.g. Prota 1992) and because it has been believed that their production is mostly under tight genetic control, precluding the possibility of condition-dependent effects and environmental influences on their production (Griffith et al 2006).…”

Section: Introductionmentioning

confidence: 99%

The expression of melanin-based plumage is separately modulated by exogenous oxidative stress and a melanocortin

2009

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Melanin-based traits involved in animal communication have been traditionally viewed as occurring under strict genetic control. However, it is generally accepted that both genetic and environmental factors influence melanin production. Medical studies suggest that, among environmental factors influencing melanization, oxidative stress could play a relevant role. On the other hand, genetic control would be exerted by the melanocortin system, and particularly by the alpha-melanocyte-stimulating hormone (a-MSH), which triggers the production of eumelanins (black pigments). To determine how the melanocortin system and an exogenous source of oxidative stress interact in the expression of melanin-based plumage, developing red-legged partridges (Alectoris rufa) were manipulated. Some partridges were injected with a-MSH, while other birds received a pro-oxidant molecule (diquat) in drinking water. Controls and birds receiving both treatments were also studied. Both a-MSH-and diquat-treated individuals presented larger eumelanin-based traits than controls, but a-MSHþdiquat-treated birds showed the largest traits, suggesting that oxidative stress and melanocortins promote additive but independent effects. Diquat also induced a decline in the level of a key intracellular antioxidant (glutathione), which is associated with high expression of eumelanin-based signals in other bird species. Some scenarios for the evolution of melanin-based traits in relation to oxidative stress are proposed.

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Melanin- versus carotenoid-based sexual signals: is the difference really so black and red?

Cited by 226 publications

References 96 publications

Melanin-based skin spots reflect stress responsiveness in salmonid fish

Melanin-based skin spots reflect stress responsiveness in salmonid fish

The size of a melanin-based plumage ornament correlates with glucocorticoid receptor concentrations in the skin of that ornament

The expression of melanin-based plumage is separately modulated by exogenous oxidative stress and a melanocortin

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