The common question of whether red attracts bugs often arises when preparing for outdoor activities like gardening or hiking. Understanding how insects perceive colors offers practical insights, as their visual world differs significantly from our own.
How Insects Perceive Color
Insects possess a visual system distinct from humans. While our eyes perceive light from violet to red, most insects’ visual range shifts towards shorter wavelengths, including ultraviolet (UV) light, blue, and green. This means they can see UV light, which is invisible to the human eye, but often cannot distinctly perceive red. To many insects, red may appear as a dark shade or black.
Insect eyes are primarily of two types: compound eyes and ocelli. Compound eyes, made of numerous ommatidia, provide a wide field of view and detect motion effectively. The number of ommatidia varies significantly across species, influencing visual resolution. Ocelli, or simple eyes, typically located on the head, detect light intensity changes, aiding orientation and regulating circadian rhythms. While ocelli contribute to light perception, compound eyes are the primary organs for detailed visual information.
Red’s Role in Insect Attraction
For most insects, red is not an attractive color because they lack the photoreceptors to distinguish it. Red objects may appear as a dark, uninteresting background. For instance, bees, important pollinators, primarily see ultraviolet, blue, and green light. Red flowers often appear dull to bees and may not attract them as effectively as blue or yellow blossoms.
A notable exception involves mosquitoes, particularly the Aedes aegypti species. Research indicates mosquitoes are attracted to long-wavelength colors like red, orange, black, and cyan, especially after detecting carbon dioxide (CO2) from breath. Human skin, regardless of pigmentation, emits a strong red-orange signal to a mosquito’s eyes, making these colors relevant for host-seeking behavior. This attraction occurs after they initially sense CO2, which primes their visual system to scan for hues associated with a potential host. Some studies also suggest certain beetles and mites are drawn to red due to its association with ripe fruits.
Practical Color Choices
Understanding insect color perception guides practical decisions for outdoor activities. For most insects that do not perceive red, wearing red clothing is generally safe to avoid attraction, applying to many common garden pests and general flying insects. However, due to mosquitoes’ specific visual preferences, avoiding red and orange clothing may be advisable if mosquito bites are a concern.
Colors that attract many insects, including bees and some flies, are often bright hues like yellow, orange, and white, especially those reflecting UV light. Yellow is frequently used in insect traps due to its strong attractive qualities. Conversely, to deter mosquitoes, opting for colors like green, blue, white, or purple can be more effective. Light-colored clothing also helps by reflecting heat, making a person less visible to mosquitoes drawn to heat and contrast.