Color Discrimination and Physiological Duplicity of Drosophila Vision

Abstract

Studies of the relative strengths of photo-taxis of following differential adaptation of the flies to various light stimuli indicate that this sp. possesses a true color vision. Ability to distinguish color is found only for high illuminations. It is lost for low illuminations though a clear phototactic response to the light remains. Color vision, therefore, appears clearly to depend upon a photopic mechanism in the eye and to lack a scotopic one. It appears that D. melanogaster possesses at least 2 color-receptive elements in its eye. Evidence is also presented to support the view that vision in Drosophila extends further into the red than formerly believed.