scholarly journals Animal coloration: production, perception, function and application

2017 ◽  
Vol 372 (1724) ◽  
pp. 20170047 ◽  
Author(s):  
Tim Caro ◽  
Mary Caswell Stoddard ◽  
Devi Stuart-Fox
Keyword(s):  
Animal Coloration ◽  
Perception Function

scholarly journals The perfection of mimicry: an information approach

2017 ◽  
Vol 372 (1724) ◽  
pp. 20160340 ◽  
Author(s):  
Thomas N. Sherratt ◽  
Casey A. Peet-Paré
Keyword(s):  
Value Of Information ◽  
Animal Coloration ◽  
Information Approach ◽  
Complex Information ◽  
Lack Of Information ◽  
Stripe Order ◽  
Future Value ◽  
Perception Function

We consider why imperfect deceptive mimics can persist when it appears to be in the predator's interest to discriminate finely between mimics and their models. One theory is that a receiver will accept being duped if the model and mimic overlap in appearance and the relative costs of attacking the model are high. However, a more fundamental explanation for the difficulty of discrimination is not based on perceptual uncertainty, but simply based on a lack of information. In particular, predators in the process of learning may cease sampling imperfect mimics entirely because the immediate pay-off and future value of information is low, allowing such mimics to persist. This outcome will be particularly likely when the model is relatively costly to attack and/or the discriminative rules the predator has to learn are complex. Information limitations neatly explain why predators tend to adopt discriminative rules based on single traits (such as stripe colour), rather than on combinations of traits (such as stripe order). They also explain why predators utilize certain salient discriminative traits while ignoring equally informative ones (a phenomenon known as overshadowing), and why imperfect mimics may be more common in phenotypically diverse prey communities. This article is part of the themed issue ‘Animal coloration: production, perception, function and application’.

scholarly journals Human colour in mate choice and competition

2017 ◽  
Vol 372 (1724) ◽  
pp. 20160350 ◽  
Author(s):  
Hannah M. Rowland ◽  
Robert P. Burriss
Keyword(s):  
Practice Guidelines ◽  
Real World ◽  
Best Practice ◽  
Blood Oxygenation ◽  
Skin Colour ◽  
Social Perceptions ◽  
Animal Coloration ◽  
Best Practice Guidelines ◽  
Apparent Colour ◽  
Perception Function

The colour of our skin and clothing affects how others perceive us and how we behave. Human skin colour varies conspicuously with genetic ancestry, but even subtle changes in skin colour due to diet, blood oxygenation and hormone levels influence social perceptions. In this review, we describe the theoretical and empirical frameworks in which human colour is researched. We explore how subtle skin colour differences relate to judgements of health and attractiveness. Also, because humans are one of the few organisms able to manipulate their apparent colour, we review how cosmetics and clothing are implicated in courtship and competition, both inside the laboratory and in the real world. Research on human colour is in its infancy compared with human psychophysics and colour research in non-human animals, and hence we present best-practice guidelines for methods and reporting, which we hope will improve the validity and reproducibility of studies on human coloration. This article is part of the themed issue ‘Animal coloration: production, perception, function and application’.

scholarly journals Fluorescence as a means of colour signal enhancement

2017 ◽  
Vol 372 (1724) ◽  
pp. 20160335 ◽  
Author(s):  
Justin Marshall ◽  
Sonke Johnsen
Keyword(s):  
Visual Communication ◽  
Energy Exchange ◽  
Signal Enhancement ◽  
Chemical Energy ◽  
Functional Feature ◽  
Animal Coloration ◽  
Pigment Molecule ◽  
Physico Chemical ◽  
Perception Function ◽  
Colour Signal

Fluorescence is a physico-chemical energy exchange where shorter-wavelength photons are absorbed by a molecule and are re-emitted as longer-wavelength photons. It has been suggested a means of communication in several taxa including flowers, pitcher plants, corals, algae, worms, squid, spiders, stomatopods, fish, reptiles, parrots and humans. The surface or object that the pigment molecule is part of appears to glow due to its setting rather than an actual production of light, and this may enhance both signals and, in some cases, camouflage. This review examines some known uses of fluorescence, mainly in the context of visual communication in animals, the challenge being to distinguish when fluorescence is a functional feature of biological coloration or when it is a by-product of a pigment or other molecule. In general, we conclude that most observations of fluorescence lack enough evidence to suggest they are used in visually driven behaviours. This article is part of the themed issue ‘Animal coloration: production, perception, function and application’.

scholarly journals Thermal consequences of colour and near-infrared reflectance

2017 ◽  
Vol 372 (1724) ◽  
pp. 20160345 ◽  
Author(s):  
Devi Stuart-Fox ◽  
Elizabeth Newton ◽  
Susana Clusella-Trullas
Keyword(s):  
Thermal Effects ◽  
Near Infrared ◽  
Adaptive Variation ◽  
Near Infrared Reflectance ◽  
Animal Coloration ◽  
Research Questions ◽  
Thermoregulatory Function ◽  
Visible Reflectance ◽  
The Relationship ◽  
Perception Function

The importance of colour for temperature regulation in animals remains controversial. Colour can affect an animal's temperature because all else being equal, dark surfaces absorb more solar energy than do light surfaces, and that energy is converted into heat. However, in reality, the relationship between colour and thermoregulation is complex and varied because it depends on environmental conditions and the physical properties, behaviour and physiology of the animal. Furthermore, the thermal effects of colour depend as much on absorptance of near-infrared ((NIR), 700–2500 nm) as visible (300–700 nm) wavelengths of direct sunlight; yet the NIR is very rarely considered or measured. The few available data on NIR reflectance in animals indicate that the visible reflectance is often a poor predictor of NIR reflectance. Adaptive variation in animal coloration (visible reflectance) reflects a compromise between multiple competing functions such as camouflage, signalling and thermoregulation. By contrast, adaptive variation in NIR reflectance should primarily reflect thermoregulatory requirements because animal visual systems are generally insensitive to NIR wavelengths. Here, we assess evidence and identify key research questions regarding the thermoregulatory function of animal coloration, and specifically consider evidence for adaptive variation in NIR reflectance. This article is part of the themed issue ‘Animal coloration: production, perception, function and application’.

scholarly journals Signal function drives phenotypic and genetic diversity: the effects of signalling individual identity, quality or behavioural strategy

2017 ◽  
Vol 372 (1724) ◽  
pp. 20160347 ◽  
Author(s):  
Elizabeth A. Tibbetts ◽  
Sean P. Mullen ◽  
James Dale
Keyword(s):  
Genetic Diversity ◽  
Genetic Architecture ◽  
Individual Identity ◽  
Signal Function ◽  
Phenotypic Properties ◽  
Animal Coloration ◽  
Behavioural Strategy ◽  
Evolutionary Consequences ◽  
Perception Function ◽  
Phenotypic And Genetic Diversity

Animal coloration is influenced by selection pressures associated with communication. During communication, signallers display traits that inform receivers and modify receiver behaviour in ways that benefit signallers. Here, we discuss how selection on signallers to convey different kinds of information influences animal phenotypes and genotypes. Specifically, we address the phenotypic and genetic consequences of communicating three different kinds of information: individual identity, behavioural strategy and quality. Previous work has shown signals that convey different kinds of information differ in terms of the (i) type of selection acting on signallers (e.g. directional, stabilizing, or negative frequency dependent), and (ii) developmental basis of signals (i.e. heritability, genetic architecture). These differences result in signals that convey different information having consistently different phenotypic properties, including the amount, modality and continuity of intraspecific variation. Understanding how communication influences animal phenotypes may allow researchers to quickly identify putative functions of colour variation prior to experimentation. Signals that convey different information will also have divergent evolutionary consequences. For example, signalling individual identity can increase genetic diversity, signalling quality may decrease diversity, and signalling strategy can constrain adaptation and contribute to speciation. Considering recent advances in genomic resources, our framework highlights new opportunities to resolve the evolutionary consequences of selection on communication across diverse taxa and signal types. This article is part of the themed issue ‘Animal coloration: production, perception, function and application’.

scholarly journals Interspecific visual signalling in animals and plants: a functional classification

2017 ◽  
Vol 372 (1724) ◽  
pp. 20160344 ◽  
Author(s):  
Tim Caro ◽  
William L. Allen
Keyword(s):  
Comparative Studies ◽  
Large Scale ◽  
Research Effort ◽  
Visual Signals ◽  
Functional Classification ◽  
Functional Requirements ◽  
Functional Categories ◽  
Animal Coloration ◽  
Visual Signalling ◽  
Perception Function

Organisms frequently gain advantages when they engage in signalling with individuals of other species. Here, we provide a functionally structured framework of the great variety of interspecific visual signals seen in nature, and then describe the different signalling mechanisms that have evolved in response to each of these functional requirements. We propose that interspecific visual signalling can be divided into six major functional categories: anti-predator, food acquisition, anti-parasite, host acquisition, reproductive and agonistic signalling, with each function enabled by several distinct mechanisms. We support our classification by reviewing the ecological and behavioural drivers of interspecific signalling in animals and plants, principally focusing on comparative studies that address large-scale patterns of diversity. Collating diverse examples of interspecific signalling into an organized set of functional and mechanistic categories places anachronistic behavioural and morphological labels in fresh context, clarifies terminology and redirects research effort towards understanding environmental influences driving interspecific signalling in nature. This article is part of the themed issue ‘Animal coloration: production, perception, function and application’.

scholarly journals The current and future state of animal coloration research

2017 ◽  
Vol 372 (1724) ◽  
pp. 20160352 ◽  
Author(s):  
John A. Endler ◽  
Johanna Mappes
Keyword(s):  
Experimental Manipulation ◽  
Model System ◽  
Broad Context ◽  
The Other ◽  
Animal Coloration ◽  
Future State ◽  
New Directions ◽  
Visual Signalling ◽  
Colour Patterns ◽  
Perception Function

Animal colour patterns are a model system for understanding evolution because they are unusually accessible for study and experimental manipulation. This is possible because their functions are readily identifiable. In this final paper of the symposium we provide a diagram of the processes affecting colour patterns and use this to summarize their functions and put the other papers in a broad context. This allows us to identify significant ‘holes’ in the field that only become obvious when we see the processes affecting colour patterns, and their interactions, as a whole. We make suggestions about new directions of research that will enhance our understanding of both the evolution of colour patterns and visual signalling but also illuminate how the evolution of multiple interacting traits works. This article is part of the themed issue ‘Animal coloration: production, perception, function and application’.

scholarly journals Colour, vision and coevolution in avian brood parasitism

2017 ◽  
Vol 372 (1724) ◽  
pp. 20160339 ◽  
Author(s):  
Mary Caswell Stoddard ◽  
Mark E. Hauber
Keyword(s):  
Brood Parasite ◽  
Future Directions ◽  
Animal Coloration ◽  
Host Interactions ◽  
Brood Parasites ◽  
Sensory Modalities ◽  
Integrative Study ◽  
Avian Brood Parasitism ◽  
Host Life ◽  
Perception Function

The coevolutionary interactions between avian brood parasites and their hosts provide a powerful system for investigating the diversity of animal coloration. Specifically, reciprocal selection pressure applied by hosts and brood parasites can give rise to novel forms and functions of animal coloration, which largely differ from those that arise when selection is imposed by predators or mates. In the study of animal colours, avian brood parasite–host dynamics therefore invite special consideration. Rapid advances across disciplines have paved the way for an integrative study of colour and vision in brood parasite–host systems. We now know that visually driven host defences and host life history have selected for a suite of phenotypic adaptations in parasites, including mimicry, crypsis and supernormal stimuli. This sometimes leads to vision-based host counter-adaptations and increased parasite trickery. Here, we review vision-based adaptations that arise in parasite–host interactions, emphasizing that these adaptations can be visual/sensory, cognitive or phenotypic in nature. We highlight recent breakthroughs in chemistry, genomics, neuroscience and computer vision, and we conclude by identifying important future directions. Moving forward, it will be essential to identify the genetic and neural bases of adaptation and to compare vision-based adaptations to those arising in other sensory modalities. This article is part of the themed issue ‘Animal coloration: production, perception, function and application’.

scholarly journals Cultural evolution of military camouflage

2017 ◽  
Vol 372 (1724) ◽  
pp. 20160351 ◽  
Author(s):  
Laszlo Talas ◽  
Roland J. Baddeley ◽  
Innes C. Cuthill
Keyword(s):  
Computer Vision ◽  
Case Studies ◽  
Cultural Evolution ◽  
The Other ◽  
Former Yugoslavia ◽  
Computational Techniques ◽  
Animal Coloration ◽  
Multiple Functions ◽  
Colour Patterns ◽  
Perception Function

While one has evolved and the other been consciously created, animal and military camouflage are expected to show many similar design principles. Using a unique database of calibrated photographs of camouflage uniform patterns, processed using texture and colour analysis methods from computer vision, we show that the parallels with biology are deeper than design for effective concealment. Using two case studies we show that, like many animal colour patterns, military camouflage can serve multiple functions. Following the dissolution of the Warsaw Pact, countries that became more Western-facing in political terms converged on NATO patterns in camouflage texture and colour. Following the break-up of the former Yugoslavia, the resulting states diverged in design, becoming more similar to neighbouring countries than the ancestral design. None of these insights would have been obtained using extant military approaches to camouflage design, which focus solely on concealment. Moreover, our computational techniques for quantifying pattern offer new tools for comparative biologists studying animal coloration. This article is part of the themed issue ‘Animal coloration: production, perception, function and application'.

scholarly journals Interactions between colour-producing mechanisms and their effects on the integumentary colour palette

2017 ◽  
Vol 372 (1724) ◽  
pp. 20160536 ◽  
Author(s):  
Matthew D. Shawkey ◽  
Liliana D'Alba
Keyword(s):  
Optical Properties ◽  
Light Scattering ◽  
Phenotypic Diversity ◽  
Selective Absorption ◽  
Physical Processes ◽  
Animal Coloration ◽  
Colour Palette ◽  
Absorption Of Light ◽  
Perception Function

Animal integumentary coloration plays a crucial role in visual communication and camouflage, and varies extensively among and within species and populations. To understand the pressures underlying such diversity, it is essential to elucidate the mechanisms by which animals have created novel integumentary coloration. Colours can be produced by selective absorption of light by skin pigments, through light scattering by structured or unstructured tissues, or by a combination of pigments and nanostructures. In this review, we highlight our current understanding of the interactions between pigments and structural integumentary tissues and molecules. We analyse the available evidence suggesting that these combined mechanisms are capable of creating colours and optical properties unachievable by either mechanism alone, thereby effectively expanding the animal colour palette. Moreover, structural and pigmentary colour mechanisms frequently interact in unexpected and overlooked ways, suggesting that classification of colours as being of any particular type may be difficult. Finally, we discuss how these mixtures are useful for investigating the largely unknown genetic, developmental and physical processes generating phenotypic diversity. This article is part of the themed issue ‘Animal coloration: production, perception, function and application’.

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