Flavonoid pigments and wing color inMelanargia galathea.

Melanargia galathea L. from four different populations were classified into three categories, white, cream, and yellow, according to the background color of their wings. The flavonoid content of the wing and body tissues of butterflies in each of these categories was spectrophotometrically determined. A direct relationship was found between the wing background color and the flavonoid content of the wings; the greater the flavonoid content, the yellower the wings. Butterflies from the yellow category contained an average of 19.6 μg flavone/mg wing tissue; those from the cream, an average of 14.1 μg/mg tissue; and those from the white an average of 8.3 μg/mg wing tissue. Flavonoids represent on average about 1.9% by weight of the yellow wings; 1.4% of the cream wings; and about 0.8% by weight of the white wings. The most frequently encountered wing background color in each of the populations examined was cream; far fewer individuals had white or yellow wings. Flavonoids were not evenly distributed in the wings ofM. galathea; greater quantities occur on the underside of the hindwings and front margins of the forewings, while the ocelli centers of the underside of the hindwings, and the inner margins on the upperside of the hindwings lack flavonoids. Furthermore, flavonoids were found in the white scales ofM. galathea but not in the black. The flavonoid content of the body ofM. galathea was found to be much lower than that of the wings. When expressed as a percentage of that in the wings, the flavonoid content of the body of both sexes was relatively constant; however, the flavonoid content of the female body represents on average about 59% of that in the wings, compared to about 20% in the male. Both the gross flavonoid content and the flavone concentration per milligram of tissue were found to be greater in female than male butterflies. Since the concentration of flavone per cm(2) of wing tissue was the same in both sexes, the greater flavonoid content of female than maleM. galathea has been attributed to the deposition of relatively large quantities in the reproductive tissues of the female. The possible role(s) of flavonoid pigments in wing coloration, in protecting vulnerable tissues from damaging ultraviolet radiation, in mate selection and/or sex recognition, in insect defense against vertebrate predators, and as antimicrobial agents inM. galathea has been discussed.