单词	melanism
释义	melanism /ˈmɛlənɪz(ə)m / noun [mass noun] chiefly Zoology Darkening of body tissues caused by excessive production of melanin, especially as a form of colour variation in animals.Adaptations to short, cool summers include activity at low temperatures, selection of warm habitats and microhabitats, melanism and hairiness coupled with basking behaviour, and prolonged or abbreviated life cycles.... However, melanism and amelanism are known to occur in many species of natricine snakes. That pattern of morphological convergence includes larger bills, reduced rust coloration in plumage, and increased melanism or dark coloration. Derivatives melanic /mɪˈlanɪk/ adjective ... There may still be very good mechanistic reasons why melanic plumage color reveals individual quality in European barn swallows, but they should have nothing to do with carotenoid signaling. We suggest that, in addition to its other functions, an important selective advantage of melanic plumage is its resistance to degradation by bacteria that are part of every bird's environment. The majority of studies on melanin ornaments cited in Table 1 measured only the size of discrete patches of melanic feathers.
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