Compound Eye

dragonfly head showing large compound eyesclose up of compound eye

The compound eyes are often the most prominent structures on the head of the insects that possess them, as is shown in the dragonfly above (photo 1). The compound eye is made up of thousands of sensory units called ommatidia, each of which has an hexagonal lens and 6-8 light sensitive cells. In the photo 2 above, the ommatidia can be clearly seen as individual hexagonal units.

Each omnatidium has a limited field of view, but sensory information from adjacent ommatidia combines to allow for an image to be 'compiled' in the optic lobe of the insect brain.

SEM photos courtesy of Kevin McKenzie, Electron Microscopy Unit, Department of Zoology, University of Aberdeen