Bees are essential pollinators, playing a significant role in plant reproduction and food production. Their ability to locate flowers efficiently depends on their unique visual perception. Understanding how bees see color provides insight into their foraging behavior and co-evolution with flowering plants.
How Bees See Color
Bee vision differs considerably from human vision. Humans typically see light in wavelengths ranging from approximately 390 to 750 nanometers (nm), encompassing red, green, and blue. Bees, however, can see light from about 300 to 650 nm. This means that while humans perceive red, bees are sensitive to ultraviolet (UV) light, which is invisible to the human eye.
Bees possess compound eyes, which are made up of thousands of tiny light-sensitive units called ommatidia. These ommatidia allow bees to detect light, color, and movement with precision. Like humans, bees have trichromatic vision, meaning their eyes contain three types of photoreceptors that are sensitive to different wavelengths. Unlike human photoreceptors, which are tuned to red, green, and blue, bee photoreceptors are most sensitive to UV, blue, and green light. This specialized vision helps them identify flowers from a distance and navigate their environment.
Colors That Attract Bees
Bees are drawn to specific colors signaling nectar and pollen. Bees are most attracted to colors in the blue and ultraviolet range, including blues, purples, and violets, which appear vibrant to them. White flowers are also attractive, often reflecting significant UV light.
Many flowers display patterns, known as nectar guides, that are visible only under UV light. These patterns act as “landing strips” or “bull’s-eyes,” directing bees toward the flower’s center where nectar and pollen are located. For example, a white flower might appear plain to humans but reveal intricate UV patterns to a bee, guiding it to its reward. These colors and UV patterns also help flowers stand out against green foliage, making them easier for bees to spot.
Colors Bees Avoid
Bees generally avoid or are less attracted to certain colors due to visual limitations or associations. Bees lack the photoreceptors to perceive red light, so red appears as a dark, often black, hue. Some red flowers may still be visited, often because they reflect UV light or other visible colors, or due to scent.
Green is another color bees are less attracted to, primarily because it blends with foliage. This camouflage makes green flowers less conspicuous. Darker colors, such as black, can also be perceived as less appealing or a threat. Bees may associate dark hues with predators like bears or skunks that raid their hives. Consequently, these colors do not effectively signal nectar or pollen.
Practical Uses of Color Knowledge
Understanding bee color preferences has practical applications. Gardeners can attract more pollinators by choosing flowers in shades of blue, purple, violet, and white. Planting these colors creates a more bee-friendly environment, supporting local bee populations and enhancing garden productivity. Examples of attractive flowers include lavender, borage, and salvia.
For beekeepers, knowing bee color perception can influence hive design. While bees may not see red on a hive, they perceive it as a dark color. Beekeepers often use white or light-colored hive components because lighter colors are less likely to agitate bees and prevent overheating. For personal safety, wearing light-colored clothing, particularly white, can minimize unwanted bee interactions, as dark colors can be interpreted as a threat. This knowledge also aids conservation efforts by informing the creation of pollinator-friendly habitats that utilize the visual cues bees respond to.