Invasive chameleons released from predation display more conspicuous colors (original) (raw)

Alternative Mating Tactics in Male Chameleons (Chamaeleo chamaeleon) Are Evident in Both Long-Term Body Color and Short-Term Courtship Pattern

Alternative mating tactics in males of various taxa are associated with body color, body size, and social status. Chameleons are known for their ability to change body color following immediate environmental or social stimuli. In this study, we examined whether the differential appearance of male common chameleon during the breeding season is indeed an expression of alternative mating tactics. We documented body color of males and used computer vision techniques to classify images of individuals into discrete color patterns associated with seasons, individual characteristics, and social contexts. Our findings revealed no differences in body color and color patterns among males during the non-breeding season. However, during the breeding season males appeared in several color displays, which reflected body size, social status, and behavioral patterns. Furthermore, smaller and younger males resembled the appearance of small females. Consequently, we suggest that long-term color change in males during the breeding season reflects male alternative mating tactics. Upon encounter with a receptive female, males rapidly alter their appearance to that of a specific brief courtship display, which reflects their social status. The females, however, copulated indiscriminately in respect to male color patterns. Thus, we suggest that the differential color patterns displayed by males during the breeding season are largely aimed at inter-male signaling.

Models painted with female-like colors elicited courtship by male common chameleons: Evidence for a courtship releaser

Journal of Ethology, 1998

Female common chameleonChamaeleo chamaeleon shows shifts in body colorations during the mating season associated with their sexual stage. The hypothesis that female colorations are used in the inter-sexual communication was tested in the field by using plastic models painted with female-like colors. Three female colorations (Neutral, Receptive and Gravid) and two artificial colorations (White and White plus black spots) as control were used. Twenty models (5 colorations × 4 replicas) were simultaneously located in the field (n=25 experiments), and the reaction by males was scored from 0 (no reaction) to 4 (copulation attempt). A male was observed nearby a model in 59 out of 500 displays. A total of 23 males (38.9%) actively reacted to the model. The response significantly differed among color types, and receptive-like models obtained the strongest response by males. In five cases, males attempted to copulate with the model. The response to receptive coloration by males agrees with previous field studies and suggests that yellow spots with a green background is a courtship releaser.

Defeated chameleons darken dynamically during dyadic disputes to decrease danger from dominants

Research on intraspecific aggression has typically focused on dominant individuals, but a better understanding of the consequences and mechanisms of agonistic encounters requires a balanced perspective that includes knowledge of subordinate animal behaviors. In contrast to signals of fighting ability, signals of submission are an understudied component of agonistic communication that could provide important insights into the dynamics, function, and evolution of intraspecific competition. Here, I use a series of staged agonistic trials between adult male veiled chameleons Chamaeleo calyptratus to test the hypothesis that rapid skin darkening serves as a submissive signal to resolve agonistic activity. Concordant with this hypothesis, I found that losing chameleons darkened over the course of aggressive trials while winners brightened, and the likelihood of darkening increased when individuals were attacked more aggressively. Additionally, I found that the degree of brightness change exhibited by individual chameleons was tied to both overall and net aggression experienced during a trial, with chameleons who received high levels of aggression relative to their own aggression levels darkening to a greater extent than individuals receiving relatively less aggression. Lastly, I found that aggression increased for losers and winners prior to the onset of darkening by the eventual loser but that both chameleons reduced aggression after the losing chameleon began to darken. Based on the theoretical prediction that signals of submission should be favored when retreat options are restricted, I suggest that limited escapability imposed by chameleon morphology, physiology, and ecology favored the evolution of a pigment-based signal of submission in this group.

The colour of success: does female mate choice rely on male colour change in the chameleon Furcifer pardalis?

Journal of Experimental Biology, 2020

Colour change is involved in various functions ranging from thermo- and hydroregulation to camouflage and communication. The role of colour change in communication has received increased attention over the past few decades, yet has been studied predominantly in the context of intrasexual competition. Here, we investigate the role of colour change in mate choice in an animal that can change its colour, the panther chameleon (Furcifer pardalis). We conducted behavioural experiments and colour analysis to investigate whether colour changes, including in the UV range, are involved in mate choice. This study presents evidence of female mate choice for specific aspects of colour change in courting males, both in the visible and the UV range. Females chose males exhibiting more saturation changes regardless of the body region and spectral range. In addition, females chose males showing fewer brightness changes at the level of the lateral line and males showing lower hue changes at the leve...