Physiological Action of Eye Color Mutants in the Moths Ephestia kuhniella and Ptychopoda seriata

Abstract

Genes found to influence eye color in the meal moth, Ephestia. are a, wa, and t. In the geometrid moth. Ptychopoda. one mutant, dec, is known. To these, rt, and om, which influence testis pigment and Malpighian vessel pigment in Ephestia. may be added. In reciprocal transplantations of testes between aa and a+a+ individuals, the grafts form pigments true to their own genotype, while a+a+ testes in aa hosts induce pigment in the eyes and testes of the host, presumably because of the secretion of a diffusable substance necessary for pigment formation. Critical and sensitive periods for pigment formation have been found for the substance a+, which likewise lacks species specificity. By means of transplantation expts., other mutant genes are analyzed for their method of action. Chemically, the substance produced in the presence of the a+ genes is kynurenin, a tryptophan derivative by way of alpha-hy-droxytryptophan.