The distribution of the long wave photoreceptors in the compound eye of the honey bee as revealed by selective osmic staining

Abstract

Compound eyes of the dark-adapted honey bees were pre-fixed with glutaraldehyde solution in the dark and post-fixed with osmium tetroxide solution in the light. The longwave light (λ⩾480 nm) was chosen to provide selective bleaching of the receptors-530 which made them clearly seen under the electron microscope. The staining is assumed to be due to a product of interaction between osmium tetroxide and products resulted from bleaching of the visual pigment. Each of the retinula was found to consist of nine visual cells. Six receptors-530 were confirmed to be in the ventral retinulae whereas only four ones in the dorsal ommatidia. The functional significance of the ninth cell is discussed as well as the role of the rhabdom cross-section shape with reference to perception of polarized light.