The common perception that the brown marmorated stink bug (Halyomorpha halys) is blind is inaccurate. This invasive insect, widely known for aggregating inside homes during cooler months, relies on a complex sensory system that integrates sight with powerful chemical and mechanical detection to locate food, find mates, and prepare for winter.
Defining Stink Bug Vision and Eye Structure
Stink bugs possess a functional visual system centered on a pair of large, reddish-brown compound eyes, confirming they are not blind. Like most insects, these eyes are composed of hundreds of individual light-gathering units called ommatidia, providing a wide field of view. This structure specializes their vision for detecting sudden movements and changes in light intensity, rather than sharp detail.
The brown marmorated stink bug has a dichromatic visual system, meaning it possesses only two types of photoreceptors. These receptors are most sensitive to two specific wavelengths: one in the green-light range (around 519 nanometers) and one in the ultraviolet (UV) range (around 367 nanometers). Lacking the blue-sensitive receptor found in many other insects, their color world is limited to combinations of UV and green light, which is crucial for finding host plants.
Navigation Through Non-Visual Senses
While eyesight is limited, stink bugs rely heavily on chemoreception, or the ability to smell and taste, primarily executed through their antennae. These antennae are covered in specialized olfactory receptors that detect airborne chemical signals over long distances. Long-range communication, such as finding other members of their species, occurs almost exclusively through the detection of pheromones.
Stink bugs are also highly attuned to mechanoreception, which involves sensing physical forces like touch and vibration. They use their legs to detect minute vibrations transmitted through the surface of a leaf or plant stem. This substrate-borne vibration is a specialized form of communication, important for short-range interactions between bugs on a plant.
Sensory Input and Stink Bug Behavior
The integration of sight, smell, and vibration drives the brown marmorated stink bug’s most important survival behaviors. The sense of smell, specifically the detection of aggregation pheromones, guides large numbers of bugs to gather in the late summer and fall. This chemical signal directs them to congregate in sheltered locations, often man-made structures, before they enter their overwintering phase.
Although vision is not the primary long-distance navigation tool, it is functional for short-range movement toward shelter and light sources. Adults are attracted to short-wavelength light, such as UV and white light, which contributes to their nuisance behavior of flying toward lamps or windows. Once drawn to the same host plant by pheromones, males and females switch to using substrate-borne vibratory signals to locate and identify each other for mating.