Why the leopard got its spots: relating pattern development to ecology in felids

Abstract

A complete explanation of the diversity of animal colour patterns requires an understanding of both the developmental mechanisms generating them and their adaptive value. However, only two previous studies, which involved computer-generated evolving prey, have attempted to make this link. This study examines variation in the camouflage patterns displayed on the flanks of many felids. After controlling for the effects of shared ancestry using a fully resolved molecular phylogeny, this study shows how phenotypes from plausible felid coat pattern generation mechanisms relate to ecology. We found that likelihood of patterning and pattern attributes, such as complexity and irregularity, were related to felids' habitats, arboreality and nocturnality. Our analysis also indicates that disruptive selection is a likely explanation for the prevalence of melanistic forms in Felidae. Furthermore, we show that there is little phylogenetic signal in the visual appearance of felid patterning, indicating that camouflage adapts to ecology over relatively short time scales. Our method could be applied to any taxon with colour patterns that can reasonably be matched to reaction -diffusion and similar models, where the kinetics of the reaction between two or more initially randomly dispersed morphogens determines the outcome of pattern development.

Ecology and Evolution of Melanism in Big Cats: Case Study with Black Leopards and Jaguars

“…In none of them has it reached fixation, but rather always exists as a polymorphic phenotype, and it is present only in two species of Panthera: the leopard (P. pardus) and the jaguar (P. onca) in contrast of the spotted wild phenotype present in these species. These observations support the hypothesis that melanism can provide an adaptive advantage in certain ecological conditions [6,16], and exists the hypothesis of an association between darker individuals and wetter areas with dense vegetation (e.g., tropical forests) [1,4,10,17]. In addition, there have also been suggestions of the potential for negative selection against dark individuals in open areas where the sunlight/radiation levels and mean temperatures are high [5,10,17,18].…”

Camouflage and Perceptual Organization in the Animal Kingdom

“…Cryptic camouflage relies on the body pattern in some sense matching its background. At present there is no simple way to predict whether two visual textures will match, yet the quality of camouflage patterns is striking, especially considering the complexity of generating naturalistic visual textures in computer graphics (Portilla & Simoncelli 2000;Peyré 2009;Allen et al 2011;Rosenholtz 2013). The lack of a simple theory for the classification of visual textures, as envisaged by Julesz (1981Julesz ( , 1984Kiltie et al 1995), has limited progress in understanding of camouflage, which leaves this area open.…”

Not all spotted cats are leopards: evidence for a Hemilienardia ocellata species complex (Gastropoda: Conoidea: Raphitomidae)

“…Colour patterns with eyespots (ocellae) are widespread in the animal world and have obviously a great adaptive significance (Allen et al 2011). Besides in various groups of seaslugs, ocellae may be present on the head-foot (as, e.g., in many ranellids and a few cancellariids) or mantle (as, e.g., in many ovulids and some eulimids) of shelled gastropods, or, alternatively, they may be part of the colour pattern of the shell (as, e.g., in various phasianellids, cowries, and columbellids).…”