title: Shape matters: animal colour patterns as signals of individual quality.
abstract: Colour patterns (e.g. irregular, spotted or barred forms) are widespread in the animal kingdom, yet their potential role as signals of quality has been mostly neglected. However, a review of the published literature reveals that pattern itself (irrespective of its size or colour intensity) is a promising signal of individual quality across species of many different taxa. We propose at least four main pathways whereby patterns may reliably reflect individual quality: (i) as conventional signals of status, (ii) as indices of developmental homeostasis, (iii) by amplifying cues of somatic integrity and (iv) by amplifying individual investment in maintenance activities. Methodological constraints have traditionally hampered research on the signalling potential of colour patterns. To overcome this, we report a series of tools (e.g. colour adjacency and pattern regularity analyses, Fourier and granularity approaches, fractal geometry, geometric morphometrics) that allow objective quantification of pattern variability. We discuss how information provided by these methods should consider the visual system of the model species and behavioural responses to pattern metrics, in order to allow biologically meaningful conclusions. Finally, we propose future challenges in this research area that will require a multidisciplinary approach, bringing together inputs from genetics, physiology, behavioural ecology and evolutionary-developmental biology.
authors.affiliation: Departamento de Ecología Evolutiva, Estación Biológica de Doñana (EBD-CSIC), Avenida Américo Vespucio 26, Isla de la Cartuja, 41092 Sevilla, Spain lorenzoperezrodriguez@gmail.com.
authors.forename: Lorenzo
authors.identifier: 0000-0002-5926-1438
authors.initials: L
authors.lastname: Pérez-Rodríguez
authors.affiliation: Departamento de Ecología Evolutiva, Estación Biológica de Doñana (EBD-CSIC), Avenida Américo Vespucio 26, Isla de la Cartuja, 41092 Sevilla, Spain.
authors.forename: Roger
authors.identifier: 0000-0002-8693-9742
authors.initials: R
authors.lastname: Jovani
authors.affiliation: Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn Campus, Penryn TR10 9FE, UK.
authors.forename: Martin
authors.identifier: 0000-0001-7768-3426
authors.initials: M
authors.lastname: Stevens
mesh_terms: D000818:Animals; D005075:Biological Evolution; D003116:Color; D010858:Pigmentation
keywords: amplifier; badge of status; coloration; developmental stability; honest signalling; melanin