Bees possess a remarkable visual system, featuring not two, but five eyes. This complex arrangement allows them to navigate their environment and locate food sources.
The Two Types of Bee Eyes
Bees have two distinct types of eyes: large compound eyes and smaller simple eyes, called ocelli. The two prominent compound eyes are located on either side of the bee’s head, giving them a wide field of view. These eyes are composed of thousands of individual units known as ommatidia or facets. Each ommatidium functions as an independent visual receptor, containing a lens and photoreceptor cells. The number of ommatidia varies, with worker bees typically having between 5,000 and 8,000 in each compound eye, while drones can have up to 11,000.
Bees also possess three ocelli, or simple eyes, positioned in a triangular pattern on the top of their head, between the larger compound eyes. Unlike compound eyes, each ocellus has a single lens and does not form detailed images. These simple eyes detect changes in light intensity rather than resolving fine details.
How Bees Use Their Vision
The different eye types work together to provide bees with a comprehensive visual understanding. The large compound eyes are primarily responsible for detecting movement, distinguishing shapes, and perceiving colors. Bees are highly sensitive to motion, capable of detecting movement that occurs as rapidly as 1/300th of a second. While their visual acuity is lower than that of humans, their ability to process rapid changes in their environment is significantly faster, allowing them to track objects quickly during flight. The composite image formed from thousands of ommatidia in each compound eye presents a mosaic-like view to the bee’s brain.
The three ocelli play a different, important role. These simple eyes detect overall light intensity and changes in brightness. This capability helps bees maintain stable flight and orient themselves, particularly when navigating in varying light conditions or when flying at high speeds. The ocelli assist in distinguishing between “up” and “down,” which is crucial for maintaining proper altitude and direction during their flights.
Beyond Human Sight: Unique Bee Vision Capabilities
Bee vision extends beyond human perception, offering unique capabilities for their survival. Bees can see ultraviolet (UV) light, a part of the electromagnetic spectrum invisible to the human eye. This ability allows them to perceive intricate patterns on flowers that act as “nectar guides,” directing them towards pollen and nectar sources. Many flowers have evolved these UV markings, appearing strikingly different to a bee than to us, signaling where to land and where rewards are located.
Bees are also sensitive to polarized light, which refers to light waves vibrating in a single plane. This specialized perception aids their navigation, even on cloudy days when the sun is obscured. By sensing the patterns of polarized light in the sky, bees can determine the sun’s position and use it as a compass reference. This navigational tool allows them to maintain their flight path over long distances and communicate food source locations through their waggle dance.