Abstract:Chameleons, lizards often synonymous with camouflage for their color-changing abilities, possess a variety of permanent coloration patterns whose evolutionary significance remains largely unknown. In this study, we explore the potential for white ventral line markings in species across the genus Chamaeleonidae to function as a camouflage pattern against diurnal predators. Diurnal behavioral field studies of the white-lined chameleon Furcifer viridis showed that individuals typically exposed ventral line markin… Show more
“…Lateral displays are positively associated with fighting ability in other male chameleon species (Bradypodion pumilum; [54]). Taken together, the findings by Resetarits & Raxworthy [53] suggest that lateral lines function as a secondary sexual signal in males and may not have an antipredator function, and that arboreal habitats increase the signal efficacy of these lateral lines to conspecifics. These findings, however, contradict our own observations on the common chameleon which demonstrated that during courtship events lateral lines are not presented.…”
Section: Contextual Appearance Of Colour Patternsmentioning
confidence: 77%
“…A recent comparative study on many chameleon species suggests that the lateral lines serve as a secondary sexual signal [ 53 ]. In their study, Resetarits & Raxworthy [ 53 ] found a positive correlation between the presence of the ventral or lateral lines and arboreal habits. They also showed in a series of behavioural trials on Chamaeleo viridis that the lateral lines were hidden from the predator and were observed only on males.…”
Section: Discussionmentioning
confidence: 99%
“…A recent comparative study on many chameleon species suggests that the lateral lines serve as a secondary sexual signal [53]. In their study, Resetarits & Raxworthy [53] found a positive correlation between the presence of the ventral or lateral lines and arboreal habits.…”
Section: Contextual Appearance Of Colour Patternsmentioning
While many animals display different colour patterns that signal different messages, some species use various tactics to separate between colour and pattern displays. The common chameleon (Chamaeleo chamaeleon) is capable of rapidly changing and separating among displays of colour patterns and ornaments. We used chameleons to study the contextual role of separation among colour and pattern displays. Specifically, we studied the predominant white badge, which is composed of multiple parts, during different seasons and in different social contexts. We hypothesized that the badge contains important information about the sender and, therefore, would be present during important social contexts. We carried out a series of trials to document the presence/absence of the badge and found that the badge is individually specific and reflects body size. We also revealed that the badge remained fixed throughout other body colour changes, but was replaced by other colour patterns during mating behaviour. During social encounters, additional dark patches delineating the badge appeared, presumably amplifying its signal. Thus, we suggest that the badge constitutes an important feature in intraspecific communication, and is possibly employed to display quality. However, the replacement of the badge by other displays during courtship suggests that during important social events like mating, chameleons transmit exclusive information that is not broadcast by the badge. Our findings demonstrate the importance of separation between colour patterns, and the alternative use of intraspecific colour patterns for specific social contexts in chameleons.
“…Lateral displays are positively associated with fighting ability in other male chameleon species (Bradypodion pumilum; [54]). Taken together, the findings by Resetarits & Raxworthy [53] suggest that lateral lines function as a secondary sexual signal in males and may not have an antipredator function, and that arboreal habitats increase the signal efficacy of these lateral lines to conspecifics. These findings, however, contradict our own observations on the common chameleon which demonstrated that during courtship events lateral lines are not presented.…”
Section: Contextual Appearance Of Colour Patternsmentioning
confidence: 77%
“…A recent comparative study on many chameleon species suggests that the lateral lines serve as a secondary sexual signal [ 53 ]. In their study, Resetarits & Raxworthy [ 53 ] found a positive correlation between the presence of the ventral or lateral lines and arboreal habits. They also showed in a series of behavioural trials on Chamaeleo viridis that the lateral lines were hidden from the predator and were observed only on males.…”
Section: Discussionmentioning
confidence: 99%
“…A recent comparative study on many chameleon species suggests that the lateral lines serve as a secondary sexual signal [53]. In their study, Resetarits & Raxworthy [53] found a positive correlation between the presence of the ventral or lateral lines and arboreal habits.…”
Section: Contextual Appearance Of Colour Patternsmentioning
While many animals display different colour patterns that signal different messages, some species use various tactics to separate between colour and pattern displays. The common chameleon (Chamaeleo chamaeleon) is capable of rapidly changing and separating among displays of colour patterns and ornaments. We used chameleons to study the contextual role of separation among colour and pattern displays. Specifically, we studied the predominant white badge, which is composed of multiple parts, during different seasons and in different social contexts. We hypothesized that the badge contains important information about the sender and, therefore, would be present during important social contexts. We carried out a series of trials to document the presence/absence of the badge and found that the badge is individually specific and reflects body size. We also revealed that the badge remained fixed throughout other body colour changes, but was replaced by other colour patterns during mating behaviour. During social encounters, additional dark patches delineating the badge appeared, presumably amplifying its signal. Thus, we suggest that the badge constitutes an important feature in intraspecific communication, and is possibly employed to display quality. However, the replacement of the badge by other displays during courtship suggests that during important social events like mating, chameleons transmit exclusive information that is not broadcast by the badge. Our findings demonstrate the importance of separation between colour patterns, and the alternative use of intraspecific colour patterns for specific social contexts in chameleons.
“…The chameleons were allowed to interact with the predator for 30 s (further durations did not elicit an additional response), with each trial being video recorded for subsequent scoring of behavioral responses. Behavioral responses were categorized as either: (i) aggression (body inflation, mouth gaping, hissing and/or lunging); (ii) fleeing (quick escape from the predator); (iii) crypsis (changing color to more closely match background); (iv) ring-flipping (rotating to the side of the branch opposite from the predator's view; Resetarits and Raxworthy, 2016 ); (v) free-falling (dropping from the branch); or (vi) leaf-mimicking (slow, back-and-forth movement imitating foliage). Fig.…”
To counterbalance demands of different selective pressures, many species possess morphological, physiological, and behavioral specializations that increase survival in their environments. Predation is one such pressure that can elicit multiple adaptive responses, and the effectiveness of antipredator behaviors likely vary both by environment and individual across time. Chameleons use multiple antipredator strategies, many of which vary with body size and habitat type. Although their unique morphological and physiological traits produce relatively slow locomotion, which is poorly suited for fleeing, chameleons can also use crypsis or aggression to avoid predation. To examine the functional basis for variable antipredator behavioral responses, we subjected chameleons to a series of mock predation trials and determined how often individuals adopted each antipredator strategy, and then quantified the performance capacities underlying each strategy. In particular, we measured bite force as a determinant for aggression, sprint velocity for fleeing, and degree of color change for crypsis. We found that aggression was predicted by traits associated with higher absolute and relative bite force, as well as habitat type; fleeing was predicted by higher normalized sprint velocity and habitat type; and crypsis was predicted by habitat type, color change capacity in bird color space and the interaction between the two. These results illustrate the importance of considering both functional capacity and environmental context in antipredator behavior decision making.
“…We observed that A. aquaticus on moss-speckled surfaces often bore more brightly colored stripes, whereas those on darker substrates bore inconspicuous stripe coloration (dark brown) (L. Swierk, personal observation). Adopting brown stripes may enhance substrate-matching on the dark substrates, whereas displaying bright, irregular stripes could be a form of disruptive camouflage against brightly mottled surfaces (Cuthill et al 2005;Resetarits and Raxworthy 2016); an examination of predator vision models and the light environments of these habitats might confirm this prediction. Such a link between coloration and camouflage would also complement our finding that stress is associated with brighter body coloration: green speckled surfaces tend to be much more exposed than uniformly dark crevices or walls, and thus green perches could be more stressful for A. aquaticus.…”
Many species use color change to optimize body coloration to changing environmental conditions, and drivers of rapid color change in natural populations are numerous and poorly understood. We examined factors influencing body coloration in the Water Anole (Anolis aquaticus Taylor, 1956), a lizard possessing color-changing stripes along the length of its body. We quantified the color of three body regions (the eye stripe, lateral stripe, and dorsum) before and after exposure to a mild stressor (handling and restraint). Based on current understanding of the genus Anolis Daudin, 1802, we hypothesized that exposure to a stressor would generate genus-typical skin darkening (i.e., increased melanism). Contrary to expectations, stress consistently brightened body coloration: eye and lateral stripes transitioned from brown to pale blue and green and the dorsum became lighter brown. Sex, size, and body temperature did not correlate with any aspect of body coloration, and a laboratory experiment confirmed that light exposure did not drive brightening. We propose that color change may serve to reduce conspicuousness through disruptive camouflage; lizards tended to display brighter stripes on mottled green-brown substrates. Together, these results improve our understanding of Anolis color change diversity and emphasize the need for a broader interpretation of the mechanism and functions of color change across taxa.Key words: Anolis (Norops) aquaticus, Water Anole, cryptic, metachrosis, physiological color change, stress.Résumé : Si de nombreuses espèces se servent des changements de couleur pour optimiser la coloration de leur corps en réponse à des conditions ambiantes changeantes, les facteurs menant à des changements de couleur rapides dans les populations naturelles sont nombreux et mal compris. Nous avons examiné les facteurs qui influencent la coloration du corps chez l'anolis aquatique (Anolis aquaticus Taylor, 1956), un lézard présentant des bandes de couleur changeante parallèles à la longueur de son corps. Nous avons quantifié la couleur de trois régions du corps (bande oculaire, bande latérale et région dorsale) avant et après une exposition à un facteur de stress léger (manipulation et retenue). À la lumière de la compréhension actuelle du genre Anolis Daudin, 1802, nous avions postulé que l'exposition à un facteur de stress produirait un assombrissement de la peau typique du genre (c.-à -d., mélanisme accru). Contrairement à ces attentes, le stress s'est uniformément traduit par une coloration plus pâle du corps, les bandes oculaires et latérales passant du brun aux bleu et vert pâles et le brun de la région dorsale devenant plus pâle. Le sexe, la taille et la température du corps n'étaient corrélés à aucun aspect de la coloration du corps, et une expérience en laboratoire a confirmé que l'exposition à la lumière ne causait pas de pâlissement. Nous proposons que les changements de couleur pourraient servir à rendre les individus moins faciles à détecter grâce au camouflage disruptif; les lézards avaie...
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