Background matching by means of dorsal color change in treefrog populations (Hyla japonica)

Abstract

Treefrogs change dorsal coloration to match background colors, presumably for predator avoidance. Dorsal coloration in treefrogs results from rearrangement of pigment granules in dermal chromatophores. This physiological basis for color change suggests that brightness and chroma are the color components that may change in response to background color. However, results of experiments are conflicting in that there is no consensus as to which color component is critical for color change in treefrogs. We tested predictions of the physiological model for color change in treefrogs by investigating dorsal color change under five background colors in three different populations of the treefrog Hyla japonica. Differences in color components between background colors and frogs were used as a measure of background matching. Throughout a 1-week experimental period, brightness and chroma differences decreased monotonically, while hue difference remained constant for all background colors. Chroma differences were smaller with the natural colors such as green and brown than with achromatic colors. Moreover, variation in color change among frogs from three localities that differed in land cover suggested that chroma change capacity may be sensitive to environmental conditions. Under the white background color, however, decreasing brightness difference seemed to be crucial to background matching. Furthermore, chroma difference and brightness difference did not decrease indefinitely, suggesting a trade-off between chroma difference and brightness difference under the white background. Thus, background matching may generally occur by decreasing chroma difference under most background colors in H. japonica, but brightness matching may be important under the white color.

Treefrog lateral line as a mean of individual identification through visual and software assisted methodologies

“…The visual identification method was successful in individual identification despite the dorsal coloration change in accordance with surrounding conditions (Choi andJang 2014, Kang et al 2016). The longest period between taking two photographs that were identified as matched by participants was 35 days.…”

Effects of substrate color on intraspecific body color variation in the toad‐headed lizard, Phrynocephalus versicolor

“…Body coloration in many poikilothermic animals (with variable internal body temperature) is generally plastic, which may show macroscopic changes within a few hours or even a few seconds, such as Paracheirodon innesi , (Nagaishi, Oshima, & Fujii, ), Pentapodus paradiseus (Mäthger, Land, Siebeck, & Marshall, ), Hyla japonica (Choi & Jang, ), and Hoplolatilus chlupatyi (Goda, ). Surprisingly, the melanic P. versicolor did not increase their reflectance value after 24 hr of treatment in weathered yellow substrate, and the same results were obtained for nonmelanic populations which did not decrease their reflectance value after translocation to dark substrate.…”

“…Body coloration in many poikilothermic animals (with variable internal body temperature) is generally plastic, which may show macroscopic changes within a few hours or even a few seconds, such as Paracheirodon innesi, (Nagaishi, Oshima, & Fujii, 1990), Pentapodus paradiseus (Mäthger, Land, Siebeck, & Marshall, 2003), Hyla japonica (Choi & Jang, 2014), and Hoplolatilus chlupatyi (Goda, 2017).…”

Geographic divergence and colour change in response to visual backgrounds and illumination intensity in bearded dragons

“…Changes in both colour and luminance are important for camouflage (Choi and Jang, 2014;King et al, 1994;King and King, 1991;Stevens et al, 2014a,b;Vroonen et al, 2012); even small changes (e.g. <2% increase in reflectance) can ultimately improve the level of background matching of an animal to its natural habitat (Stevens et al, 2013).…”

“…Consequently, background colour and pattern is a common environmental cue eliciting colour change in a variety of taxa (Chiao and Hanlon, 2001;Choi and Jang, 2014;Stevens et al, 2014a). Background colour may also interact with other environmental cues such as illumination to influence colour change and camouflage.…”