While spiders, ants, and flies are considered "house bugs," most homeowners want these creatures to be anywhere except in the house. If you understand house bugs and how they get into a home, you can more effectively prevent them from finding a way inside in the future.
Spiders are from the arthropod family of animals. They are not insects. Some common varieties of spiders that you are likely to find inside a home include fishing spiders (commonly found around pounds and swamps), sac spiders (which live in trees or the ground when outdoors) and crab spiders (which have crab-like legs and a bulbous body).
Spiders are not always seen as a major pest inside of the home because they tend to live in out-of-the way corners of the house. They are also helpful to homeowners because they catch and eat other annoying house bugs like flies.
To prevent spiders from entering your home, you have to plug up holes in your walls, floors, and windows. Spray crevices with a good bug spray, like Raid Max.
Flies get indoors through cracks in the window and when humans open doors. While they cannot bite or harm humans, flies are one of the most common household pests for several reasons. They are airborne and can quickly find their way into human food, and they are commonly found in garbage and on animal feces, so they carry germs. House flies can transmit up to 65 diseases.
To stop flies from getting inside you have to assure that the doors and windows of your home do not stay open for long periods of time.
Another household annoyance is ants. This insect has a knack for finding its way into a home through even the smallest crevice due to its small size (some can be as tiny as 1/20th of an inch). Worker ants are charged with finding food for the colony, so they forage in homes in droves. Carpenter ants are one of the most common ants that you might find inside your home.
You must use an ant killer like Terro (terro.com) to stop ants from finding their way inside. The ants eat the bait and then bring it back to the colony.
Boxelder bugs are commonly called "Halloween" bugs because they are black and orange in color. These flying bugs travel in packs and swarm in groups to the sunny side of the outside of a home. Then they seek to get inside of the home through crevices. They are harmless to humans.
To prevent them from coming inside, go outside your home to look for a grouping of Halloween bugs. Spray the swarm of insects with a strong bug spray.
Unlike other house bugs, fleas are not common and they do not come into the house on their own. They are parasitic bugs that find their way into a home on the back of an animal. Fleas are pests in a home because they bite humans and animals (blood is a flea's food) and quickly grow in numbers. In addition to bites, animals can get tapeworms from swallowing fleas. Many humans are allergic to flea bites.
To avoid fleas in the home, treat all of your animals with a topical flea prevention product, like Revolution or Frontline.