Other than its blocky shape, the most distinguishing feature of a honey bee drone is its eyes. They are huge, cover a large portion of its head, and nearly meet in the middle. Why so big?
The single function of a honey bee drone is to mate with a young queen. The large, well-developed eyes—along with extra sensitive antennae—allow the drone to track down the powerful, high-flying young queens. Together, the eyes and antennae provide a tracking system of the first order.
A mature drone goes to a drone congregation area (aka singles bar) and waits for young a queen to fly overhead. The drone senses queen pheromone with his antennae and can see her through the top-mounted eyes. Only the fastest and most skillful fliers will be able to mate—an accomplishment with a great price. After mating, the sexual organs are ripped from the drone’s body and it will soon die.
Compound eyes are an aggregation of many individual photoreceptors—called facets or ommatidia—arranged on a convex surface. The image the bee sees is a combination of all the ommatidia taken together. Compound eyes allow the bee to have a very wide field of vision, to detect extremely rapid movements, and to sense polarized light. On the other hand, bees have poor visual resolution; they cannot make out the details of a flower until they are within a few centimeters of it.
The compound eyes of a drone each comprise about 7000-8000 facets. Worker compound eyes each contain 4000-5000 facets, and the queen has smaller eyes containing about 3500 facets.
Honey bees actually have five eyes—two of the large compound type and three much smaller ocelli. While the compound eyes can detect color, shape, and movement, the ocelli are light sensors only. Ocelli can detect changes in light intensity but no actual images.
In the queen and workers the three ocelli are on the top of the head, centered between the two compound eyes. In a drone, the three ocelli are just in front of the area where the compound eyes meet.
Honey bees cannot detect long wavelengths such as the color red. Red appears black to a honey bee. On the other hand, they can see some of the shorter wavelengths—such as ultraviolet—that humans cannot see. Many flowers have evolved with ultraviolet patterns on their petals. These colorful patterns attract honey bees and other insects to the flower to help assure that pollination occurs.