Brown fungus beetles are non-native insect pests that belong to the Latridiidae family, which is comprised of many beetle pests that are commonly found in homes. These beetle pests are light to dark brown in color, but their 1 millimeter body length makes them extremely hard to see. Just as their name suggests, brown fungus beetles congregate in decaying organic matter and fungal spores where larvae graze and adults feed on moldy slime. In their native region, these beetles are attracted to outdoor sources of decay, mold and fungus, but in their non-native US habitat, brown fungus beetles are found in homes and other human dwelling more often than in the natural environment. These beetles gather in large numbers in indoor areas that are high in moisture, such as bathrooms, kitchens and basements, and their presence is indicative of an indoor mold issue. While several species infest homes in Louisiana, one species, Eufallia seminivea, has become particularly well known as the only one of these pests that inflict bites to humans. This species is more commonly known as the “man-biter,” and although this species’ bite has been documented as causing itchiness and inflammation, it is not considered medically significant.

The man-biter does not necessarily need to secure a moldy location for egg laying, but females must deposit eggs on organic matter. While they prefer moldy conditions, a high-moisture environment is enough to sustain large congregations of brown fungus beetles. Some brown fungus beetles may attempt to puncture skin with their needle-like mouthparts, but only the man-biter has been repeatedly documented as inflicting bites to humans. Residents of infested homes often sustain multiple bites from these insect pests without provocation, but luckily, the man-biter does not feed on human blood or spread disease. Brown fungus beetles are common in homes that contain wet drywall that was not properly cured. Chemicals can be used to temporarily eliminate infestations, but long term prevention requires significant dehumidifying treatments in order to eliminate indoor moisture and mold.

Have you ever heard of brown fungus beetles? Do you believe that you have sustained a bite from a man-biter?