Common Fall Invading Insects in Homes

 

During the fall, many insects start searching for warm, sheltered places to survive the colder months. Homes provide an ideal refuge, so it's very common to see more insects indoors as the weather cools. The most frequent fall home invaders are boxelder bugs, ladybugs (more accurately called lady beetles, especially the Asian lady beetle), stink bugs, cluster flies, spiders, and certain types of ants and crickets.

 

Boxelder Bugs

 

Boxelder bugs are black with reddish-orange markings on their wings and body, usually about half an inch long. They feed on trees, especially boxelder, maple, and ash, but in the fall, they gather in large groups on warm surfaces and seek out cracks around windows, doors, and siding to get indoors. While they don’t bite or damage structures, their droppings can stain walls and fabrics, and their presence in large numbers can be disturbing.

 

Asian Lady Beetles

 

Often mistaken for native ladybugs, Asian lady beetles are slightly larger and have various colorations from orange to red with or without black spots. In the fall, these beetles gather in masses on sunny sides of buildings and find ways indoors through even small gaps. Once inside, they sometimes release a yellowish fluid that can stain surfaces and has an unpleasant odor. They don’t pose health risks but can be a nuisance, especially when present in large numbers.

 

Brown Marmorated Stink Bugs

 

These shield-shaped insects are brown and roughly the size and shape of a dime. They seek out homes in the fall for warmth. If crushed or disturbed, they release a strong, unpleasant smell, hence their name. Stink bugs do not cause structural damage or bite people, but they can appear in large numbers and become a persistent annoyance throughout winter if they get inside.

 

Cluster Flies

 

Cluster flies look similar to common house flies but are slightly larger and slower. In the fall, they gather in large numbers on sun-warmed walls and squeeze into attics, wall voids, and unused rooms. They get their name because they often “cluster” together in big groups. While they do not breed indoors, cluster flies can emerge during warm winter days, lazily flying around, and become bothersome.

 

Spiders

 

Spiders themselves are not seeking warmth; rather, they are following their prey, which also comes indoors during fall. However, you might notice more spiders during the fall as they build webs in corners of ceilings, basements, and attics. Most house spiders are harmless and rarely bite, but their webs and sudden appearances can alarm residents.

 

Other Common Invaders: Crickets and Ants

 

• Crickets: House and field crickets may seek shelter indoors to escape cold. They’re recognized by their chirping and can damage fabrics or paper products inside the home.
• Ants: Certain species, like pavement ants or carpenter ants, may look for indoor shelter or food, especially as outdoor food supplies dwindle.

 

Why Do These Insects Invade in Fall?

 

As temperatures drop outside, insects instinctively seek warmth and protection. They find tiny openings around windows, doors, vents, siding, and utility pipes. Homes, with their steady temperatures and lack of predators, offer a safe haven until spring returns.

 

What Should You Do If They Get Inside?

 

• Seal Entry Points: Check for and patch up cracks, gaps, damaged screens, and weatherstripping to make it harder for insects to get inside.
• Vacuum Regularly: For harmless invaders like lady beetles or boxelder bugs, the best removal method is vacuuming. Dispose of the vacuum bag afterwards.
• Avoid Crushing: Crushing stink bugs or lady beetles can cause more odor or staining. Instead, use gentle means like a cup and paper or a vacuum.
• Reduce Outdoor Attraction: Move firewood away from the house, keep gardens tidy, and manage outdoor lighting to avoid attracting bugs to your exterior walls.
• Call a Professional: If you have large infestations or want preventative treatments, consult a pest management professional. They can offer proper barrier treatments or identify less obvious entry points.

You can expect to see these fall invaders most commonly, but with good preventative steps, you can reduce or avoid indoor insect problems through the colder months.