Study Of Ultrastructure Of The Compound Eye And The Optic Lobe Of The Ant Camponotus Japonicus

Used the routine electron microscopic technique, the ultrastructure of the compound eye and the optic lobe of the female ant Camponotus japonicus was studied. The results are rendered as follows: The compound eyes are composed of many ommatidia, and each ommatidium is composed of nine photoreceptor cells. In all ommatidia, all photoreceptors contribute at least some microvilli to the central rhabdom, the light sensitive structure. In these ommatidia, two to five microvilli directions can be distinguished within given rhabdom cross sections. Neighboring photoreceptors of each ommadium bundle their microvilli to form a microvillar tuft in which all microvilli are oriented in parallel. However, the microvilli themselves are sometimes not strictly straight but slightly curved within rhabdom cross-sections. . In cross-sections, rhabdom shapes change greatly. Shapes of the rhabdom in retina of the ant Camponotus japonicus exhibit lingua shape, triangle, pentagon, and irregular polygon, and maybe, which are possibly related to receiving the light of different color and intensity. Longitudinal sections of the rhabdom appear long-pole shape, and show some bent. In different ommatidia cross-sections, where the membrane of neighboring photoreceptor cells join, two to five roughly circular membrane-limited bodies, which may be centrifugal fibers, are observed. In addition, the pigment granules layer is observed between retina and basement membrane, in which plenty of pigment granules are found, and whose function may be light reabsorption. The basement membrane is composed of many microfibrils and acellular structure material, whose function is possibly mechanical support to stabilize the ommatidia. After passing the basement membrane, the nine axons from each retinal ommatidium of the ant form one axonal bundle, and then project into the lamina ganglion. In the distal area of lamina ganglion, these fiber bundles are named as pseudocartridge, in which there are no synaptic contacts. But below the pseudocartridges, the synaptic contacts formed on fibers are observed, and most of which are mutli-synaptic contacts. This suggests that mutli-synaptic contacts play an important role in the visual system of the ant. And in the proximal area of the optic lobe, some neurons, which have a large nucleus and indented folded plasmalemma, are observed, and whose cytoplasm contains a small number of mitochondria. In addition, a lot of large fiber bundles containing more than 30 fibers are observed in the optic lobe, and it is assumed that they may belong to medulla.