The brown marmorated stink bug is a common household pest that often prompts concern when it appears indoors, particularly during the cooler months as it seeks shelter to overwinter. While primarily known for its invasive status and damaging effect on agricultural crops, its presence inside homes leads many to wonder if it poses a threat to people. The brown marmorated stink bug does not bite humans or pets, nor does it sting, suck blood, or transmit diseases. The perceived threat stems from its habit of entering buildings in large numbers and its potent defensive chemical release when disturbed.
Identifying the Brown Marmorated Stink Bug
The adult brown marmorated stink bug is easily recognized by its distinct shield shape, a characteristic common to the family Pentatomidae. It measures approximately 14 to 17 millimeters long, roughly the size of a U.S. dime. The bug’s body has a mottled brown and gray coloration, which helps it camouflage against natural surfaces. A defining feature that distinguishes this species from other native stink bugs is the alternating light and dark bands present on its antennae. Alternating bands of black and white are also visible along the thin outer edge of its abdomen. These insects are most frequently noticed in the fall when adults gather on the exterior of structures, seeking protected locations to spend the winter.
The Direct Answer: Do They Bite Humans?
The brown marmorated stink bug cannot bite a person because its specialized mouthparts are designed exclusively for feeding on plants. Like all true bugs, this species possesses piercing-sucking mouthparts, known as a proboscis. This apparatus is modified into a long, straw-like structure used to pierce plant tissue, such as fruits, leaves, and stems, allowing the bug to extract fluids. The proboscis contains fine, needle-like stylets that are not strong enough to penetrate human skin. Their function is to access the internal tissues of plants, not to feed on animal tissue. Therefore, the bug has no biological motivation or mechanism to bite a person or a pet.
The True Nuisance: Understanding Their Defense Mechanism
While they do not bite, the primary negative interaction humans have with the brown marmorated stink bug is the release of a strong, unpleasant odor. This odor is a chemical defense mechanism used to deter predators. The odorous compounds are stored in glands located on the underside of the thorax and the dorsal surface of the abdomen. This defensive spray is typically triggered when the bug is startled, handled, injured, or crushed. The smell has been described as pungent, similar to cilantro, or sometimes likened to a bitter, metallic scent. Although the chemicals are non-toxic, direct contact with the bug’s body fluids can cause minor skin irritation in rare cases.
Safe Handling and Removal
Because the defensive odor is released upon disturbance, the goal of removal should be to handle the insect without crushing it. The most effective non-toxic method for eliminating them indoors is using a vacuum cleaner. Note that the bugs can cause the vacuum canister or bag to temporarily smell, so a dedicated vacuum or a stocking placed over the hose can help contain the odor and the insects. A simple alternative is to sweep or brush the bugs into a container filled with soapy water. The soap breaks the surface tension, causing the insects to drown quickly. Sealing entry points like cracks around windows, doors, and utility pipes with caulk is the best long-term strategy to prevent them from entering the home.