Honey bees sleep with their eyes open. They must. They have no eyelids and hence no way to close them.
Arranged in a triangle atop honey bees’ heads are three simple eyes, called ocelli. Shiny, black and relatively small, these eyes are considered simple because they are composed of one lens facet each and thought not to render a visual image but instead to assist the bee in determining the intensity and direction of the sun.
The two larger complex eyes sitting astride the head are made up of thousands of hexagonal facets called ommatidia. Male honey bees’ have comparatively huge eyes, which boast almost twice as many facets, as females. The eyes are spherically shaped, which allow bees to measure angles, with astounding accuracy, between relative positions of the sun and horizon. They are even able to accomplish this feat on cloudy days as a result of their ability to see ultraviolet and polarized light. Honey bees perceive yellow, blue-green, blue, violet and a color known as bee’s purple (a mixture of yellow and ultraviolet). Bee’s purple, though hidden from our eyes is used by many species of flowering plants to paint a virtual bull’s eye on their petals, announcing the pollen and nectar located at the center of each bloom. Honey bees’ eyes also capture information relating to movement and patterns. Finally, their eyes are covered in hairs, creating more surface area on which to collect pollen and help, it is thought, the bee to determine the direction of the sun, aiding orientation and navigation.