Biology of Eye Pigmentation in Insects

Abstract

Publisher Summary The color of insect eyes is determined largely by the nature of the screening pigments which they contain. These pigments are not involved in light detection but they function to isolate optically each facet of the compound eye from its neighbors and thus enhance contrast sensitivity and visual acuity. This chapter focuses on developments since 1974 and draws attention on information gained from the study of dipteran species, although reference will be made to other insect species where appropriate. It describes ultrastructural information concerning the nature of the dipteran peripheral retina and the location of the screening pigments within the eyes. The biochemistry of the two types of compound that function as screening pigments in insect eyes, the ommochromes and the pteridines, has been considered. The chapter discusses the biosynthetic pathways that lead to the production of these two classes of screening pigment and also the characteristics of those eye color mutants, in various insect species, which lack a specific enzyme of the pathways. The interrelationships between the ommochrome and pteridine pathways and the possible functions of genes that affect the production of both types of screening pigment have been discussed.