The Brown Marmorated Stink Bug (BMSB), Halyomorpha halys, is an invasive insect that has become a significant household pest across North America and Europe. This shield-shaped insect is notorious for seeking shelter indoors to survive the winter, a behavior known as overwintering. When disturbed, the bugs release a pungent, defensive odor, turning a simple pest problem into a major nuisance for homeowners. Understanding how the stink bug perceives its environment, particularly light and color, offers a practical approach to managing their presence.
How Stink Bugs Perceive Light and Color
Stink bugs possess compound eyes, which allow them to process light and visual cues differently than humans. Their vision is rooted in a sensitivity to specific wavelengths, a factor that influences their behavior, including their movement toward light (phototaxis). Scientific analysis of the BMSB’s visual system reveals two primary types of light receptors.
These receptors are tuned to detect light in the ultraviolet (UV) range, peaking around 367 nanometers, and in the green-yellow visible range, peaking near 519 nanometers. This gives the insect a form of dichromatic vision, allowing them to perceive differences between UV and green light. The strong sensitivity to UV light explains why they are frequently drawn to light sources that emit UV rays, such as black lights or certain outdoor lamps.
Colors Proven to Be Repellent
The question of which color stink bugs “hate” is best answered by identifying the colors they are least attracted to. Research shows that Brown Marmorated Stink Bugs are attracted to various colors when compared to complete darkness, making it difficult to define a truly repellent color. However, the level of attraction varies significantly across the spectrum.
White light, which contains a broad spectrum of wavelengths including highly attractive UV, consistently proves to be the most attractive stimulus for the BMSB. In contrast, the longer-wavelength colors, such as yellow, orange, and red, are significantly less attractive to the bugs than white light. While these colors do not actively repel the insect, they offer a low-attraction alternative. The colors that are furthest from their peak sensitivity points (UV and green) are the ones that minimize the phototactic response.
Using Color as a Practical Deterrent
Homeowners can use the knowledge of the BMSB’s visual preferences to implement simple, non-toxic deterrent strategies. The primary application involves manipulating the light sources used around the exterior of the home. Since white light is a major attractant, switching outdoor lighting is the most effective color-based modification.
Replacing standard white porch lights and security lights with yellow bug lights or sodium vapor bulbs can drastically reduce the number of stink bugs drawn to the house at night. These yellow-spectrum bulbs emit light at longer wavelengths, which the stink bug’s visual system is less sensitive to, thereby making the home less visible to the pests. Furthermore, the bugs are also drawn to large, light-colored surfaces. Reducing the amount of white or light-colored paint on exterior trim and siding can help make the home less appealing as a potential overwintering site.