The black house cricket is a dark-bodied, omnivorous insect that commonly moves indoors during cooler months or when doors and windows are left open. Adults grow up to 30mm (about 1.2 inches) long, have brown wings folded flat along their backs, and large hind legs built for jumping. They’re harmless to people but can damage fabrics and keep you up at night with persistent chirping.
What They Look Like
Black house crickets have a grasshopper-like body shape with a dark brown to black coloring. Their heads and mouthparts point downward, and their antennae are long and thread-like, often as long as or longer than their bodies. Wings lie flat against the back when at rest.
Young crickets (nymphs) look similar to adults but are smaller, paler, and wingless. Very small nymphs sometimes have a distinctive white band across their backs. As they grow through several molts, they darken and eventually develop full wings.
Why They Come Inside
Crickets are drawn to moisture and warmth. They often enter homes accidentally through open doors or windows, but fall weather is the biggest trigger. As outdoor temperatures drop, crickets seek out heated spaces and can establish themselves indoors for the entire winter. Once inside, they gravitate toward kitchens, areas near water heaters, fireplaces, and furnaces, anywhere that stays warm and slightly humid.
Light is another major attractant. Outdoor porch lights and bright windows pull crickets toward your home’s exterior, and from there it’s a short hop through any gap in a door seal or torn screen.
House crickets can complete their entire life cycle indoors if they find enough food and moisture, so a small seasonal invasion can become a year-round presence if left unchecked.
What They Eat and Damage
Black house crickets are omnivores. They’ll feed on crumbs, pet food, cardboard, paper, and organic debris. Outdoors they eat plants, decaying material, and other insects. Indoors, the real concern is fabric damage. Crickets chew on clothing, curtains, and upholstery, with a strong preference for items soiled with perspiration or food stains. Silk and wool are especially vulnerable.
The damage typically shows up as irregular holes or frayed areas, similar to what you’d see from moth larvae. A single cricket won’t destroy a wardrobe, but a group of them in a closet or basement can cause noticeable harm over time.
The Chirping
Male crickets chirp by rubbing their wings together rapidly, a technique completely different from how grasshoppers make noise. The primary purpose is attracting females, though males also chirp during aggressive encounters with other males and as a danger signal.
Chirping speed changes with temperature. Crickets are cold-blooded, so their muscle activity directly mirrors the surrounding air temperature. On warm nights, they chirp faster. As it cools down, the rate slows. Below about 50°F (10°C), they stop chirping entirely. This relationship is reliable enough that you can roughly estimate the outdoor temperature by counting chirps, though indoors the warmth of your house keeps them vocal year-round.
Because crickets are nocturnal, the chirping is loudest at night. A single male in a quiet bedroom can be surprisingly disruptive.
Are They Dangerous?
Black house crickets pose no meaningful health risk. They don’t bite or sting, and they aren’t known to transmit diseases to humans. The only real concerns are fabric damage and noise. If you find one on your skin, it may try to jump away but won’t hurt you.
How to Get Rid of Them
Start by cutting off their entry points. Check door seals, window screens, and any gaps around pipes or vents leading outside. Caulk cracks around window frames and replace worn weather stripping on exterior doors. These same steps reduce other pest problems too.
Non-Toxic Methods
A simple molasses trap works well: put a few spoonfuls of molasses in a shallow bowl, fill it halfway with water, and place it where you’ve heard or seen crickets. The sweet smell draws them in and they drown. Sticky glue traps placed along baseboards in kitchens and basements also catch crickets reliably.
Diatomaceous earth (DE) is another effective option. Sprinkle it around baseboards and in wall crevices. The fine powder scratches the cricket’s outer shell, causing it to dehydrate and die within a day or two. DE is non-toxic to humans and pets, making it safe for households with children.
Reducing Attraction
Switch outdoor lights near doorways to amber-colored bulbs or motion-activated fixtures. Crickets are far less attracted to amber light than standard white bulbs. Inside, reduce moisture in basements and crawl spaces with a dehumidifier or improved ventilation. Store garbage in sealed containers elevated off the ground, since food waste is a reliable draw.
Chemical Options
Insecticide sprays applied along windowsills, in room corners, and around exterior doors can kill crickets on contact. Let treated surfaces dry completely before allowing pets or children into the area. For outdoor control, granular lawn insecticides applied in early summer can reduce cricket populations before fall migration begins. Spray treatments around garage doors, basement vents, and exterior pipes create a barrier that discourages entry.
Preventing Future Infestations
The most effective long-term strategy combines sealing entry points with reducing what attracts crickets in the first place. Keep your home’s perimeter clear of tall grass, leaf litter, and woodpiles, all of which shelter crickets close to your walls. Move firewood storage at least 20 feet from the house. Inside, store wool and silk clothing in sealed containers, especially items you don’t wear regularly. Keeping indoor humidity low makes your home far less appealing as a cricket habitat, particularly in basements and utility rooms where they tend to settle first.