著者

Shirakata Yoshinori 上島 孝久

出版者

中国学園大学/中国短期大学

雑誌

Chugokugakuen journal (ISSN:13481452)

巻号頁・発行日

vol.5, pp.17-21, 2006

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Japanese tree frogs are known to change their body color readily according to external (ambient) or internal (mental) conditions. The coloration of the frog skin is shown by pigment cells distributed under the epidermis. Pigment cells in amphibians are classified into three types: melanophores, iridophores and xantophores. These pigment cells in the dorsal skin are formed chromatophore units, each of which consists of three different types of pigment cells. In the chromatophore unit, these pigment cells are layered one on the other: that is, a melanophore on the innermost layer, a xanthophore on the outermost and an iridophore in the middle. Various colors of the chromatophore unit combines spectra from each pigment cell, and the total skin color of a certain area results from a combination of colors from chromatophore units in the area. In this study, we examined how the chromatophore unit can show various colors, and to what extent it can exhibit a color range in relation to its component pigment cells. We also examined the total skin coloration in relation to the chromatophore unit deduced by computer calibration. It was also determined that the various patterns of brown or black stripes, which appeared against the green background skin, were caused by differences of MSH sensitivities of melanophores in the skin area.