Eye development and photoreception of a hemimetabolous insect, gryllus bimaculatus

Abstract

The hemimetabolous insect, Gryllus bimaculatus, has two compound eyes that begin to form in the embryo and increase in size five- to sixfolds during nymphal development. Retinal stemlike cells reside in the anteroventral proliferation zone (AVPZ) of the nymphal compound eye and proliferate to increase retinal progenitors, which then differentiate to form new ommatidia in the anterior region of the eye. Here, we introduce the morphology and development of the cricket eye first, and then we focus on the roles of retinal determination genes (RDGs) such as eyes absent (eya) and sine oculis (so) in Gryllus eye formation and growth. Since the principal function of the eye is photoreception, we finally summarize opsin photopigments in this species, broadening the roles of photoreception.