The Brown Marmorated Stink Bug (Halyomorpha halys) is an invasive species that often seeks shelter inside homes during cooler months. These shield-shaped insects frequently appear suddenly, crawling across walls or flying toward light sources after sunset. Understanding how this common pest perceives its environment in low-light conditions is important for management. This article explores the visual and non-visual senses the stink bug utilizes for movement and survival in dim light.
Low-Light Vision Capabilities
The brown marmorated stink bug is active during periods of dim light, such as dusk and dawn, and navigates effectively at night. Its compound eyes are highly adapted for detecting light and movement. Adults exhibit phototaxis, meaning they are attracted to light sources, a behavior especially noticeable when seeking overwintering sites in the fall.
Spectral Sensitivity
Experiments show that the stink bug’s eyes are most sensitive to light in the green spectral range (peaking at 519 nanometers). They also exhibit a strong secondary sensitivity peak in the ultraviolet (UV) range (around 367 nanometers). This dual sensitivity allows them to process small amounts of ambient light, enabling them to perceive shapes. Their attraction is strongest in shorter wavelengths (UV and blue), causing them to congregate near artificial light sources.
How Compound Eyes Function
The stink bug’s ability to see in low light is determined by the specialized structure of its compound eyes. Like most insects, the eyes are composed of thousands of individual visual units called ommatidia, each acting as a separate light sensor. This arrangement prioritizes light-gathering capability and motion detection over high-resolution detail, a common trade-off for insects active in dim environments.
Dichromatic Vision
Scientific analysis reveals the stink bug’s visual system relies on only two types of photoreceptor cells, a condition known as dichromatic vision. These two photoreceptor types correspond to the sensitivity peaks in the green and ultraviolet parts of the spectrum. Green light sensitivity helps them see in the visible spectrum, while UV sensitivity may be used for orientation, finding mates, or locating host plants. This lack of a third photoreceptor means their color vision is limited, but their overall light sensitivity is enhanced.
Senses Used for Night Navigation
When a stink bug is in complete darkness, its visual senses are useless, and it relies on non-visual mechanisms for navigation. The antennae are the primary sensory organs, equipped with specialized receptors.
Chemoreception and Mechanoreception
These appendages facilitate chemoreception (smell and taste), allowing the insect to detect volatile chemicals. Stink bugs use this chemical sense to locate one another, especially when seeking an aggregation site or finding a mate. They produce and track pheromones, which are chemical signals that communicate information over long distances. For shorter distances, the insects employ mechanoreception, sensing vibrations transmitted through solid surfaces. Specialized hairs and receptors on their body and legs detect these low-frequency vibrations, helping them communicate and navigate physical obstacles.