Uric acid in Anopheles mosquitoes (Diptera: Culicidae): Effects of collarless, stripe, and white mutations

Abstract

Anopheles mosquito larvae and pupae often have a layer of white pigment visible beneath the transparent cuticle on the dorsum of the abdomen and thorax. This pigment occurs in granules that are highly concentrated in ameboid-shaped cells of parietal fat body. Mutation that affect the pattern or abundance, or both, of this pigment in A. albimanus Wiedemann and A. gambiac Giles are characterized by differences in the abundance of uric acid, whose levels range from 1.86 to 3013 μg per larvae in individuals of 4 phenotypes having white pigmentation. Uric acid concentration are higher in A. albimanus stripe' individuals which also have the most prominent white pigment. Two other mutants, A. gambiac collarless and A. albimanus white eye, contain no detectable uric acid nor any white pigment. None of the mutants examined has reduced xanthine dehydrogenase activity nor altered XDH electrophoretic mobility. We suggest that the prominent white pigment is precipitated uric acid contained within specialized fat-body cell similar to urocytes. We discuss the genetic basis of mutants affecting uric acid deposition, and the pleiotropic effects of the eye-color mutation such as white.