House Spiders

House Spiders Identification

The length of the body of female house spiders is about 5 to 8 mm long, which includes their spherical abdomen. The length of male house spiders are slightly smaller ranging from 3.8 to 4.7 mm long including their elongated abdomens. Colors vary but house spiders are typically a yellowish – brown color. The abdomens of house spiders are a dirty white to almost grayish color. There are a few dark and almost black spots or markings that can be noted on the abdomen. They can also be characterized by their dark chevron shaped stripes that are located right above the top of the abdomen. The legs of a house spider are more vivid and are orange in color for the males and yellow in color for females. There are rings around the ends of each segment giving their legs a banded look.

Biology of House Spiders

Adult female house spiders lay eggs in sacs that are brownish in color. They are oval shaped and about 6 to 9 mm in diameter. Each sac can contain about 250 eggs. Each female can actually produce more than one sac at one time. Therefore, sometimes, there can be more than one egg sac that is found on the web at a time. In her entire lifetime, a female house spider can produce up to 17 egg sacs which mean that she can produce more than 4000 eggs in her entire lifetime. Usually, females will place her egg sac in the center of the web; however, if conditions are favorable towards a certain part of the web, like on warmer or cooler sites of the web, she will move them there as required.

It takes about 10 days for the eggs to hatch. Even though the newly hatched spiders have emerged from their eggs, they will remain in the egg sac for about 1 day and emerge from the egg sac as a second instars. Once they emerge, the young spiders are ready to balloon. When a house spider balloons, it points its abdomen towards the air and releases a fine thread of silk. The wind then catches the piece of fine thread and carries the spider away. House spiders molt about 7 times until they are fully matured adults. Once they have completed development, adult house spiders will live for about a full year.

Behavior of House Spiders

Before a house spider spins its web, it will randomly select an area. Selection is made based on trial and error. That means that if the initial placement of the web does not yield any food, then the web is ultimately abandoned. A new location is selected for harborage and a brand new web is built. This process continues until a successful web is constructed. A successful web is defined by the prey that it yields. Because spiders feed on small insects that have been caught on the web, the survival rate of house spiders depends on the location of the web. In places like modern homes where there are just few insects and low humidity, the survival rate of house spiders are very low. Rarely are new generations produced inside a modern home. Survival rates are a little bit higher in areas that are located outside like in barns, garages, and sheds. These types of areas yield more prey and are generally of higher humidity. They are also less disturbed and so chances of survival in outer locations are higher than inside modern homes. However, survival rates are the highest in the outdoor environment in protected areas like under trees, under the eaves of buildings, under a deck or in a crawl space.

Web selection made on a trial and error basis means that there may be multiple webs that are constructed within just a few days. Initially, webs are almost unnoticed, however, inside modern homes or commercial buildings, dust build up will make the nest more noticeable. Because cobwebs are associated with unsanitary living situations, many homeowners or business owners will remove webs as soon as they are noticed, which also affects the survival rate of house spiders.

Inside buildings, house spiders and their webs are most commonly found in places like the upper corners of rooms, under the furniture, in basements, attics and etc. Inside commercial areas, they may construct webs in similar areas as well as on or near doors and windows that remain open. Outside, homeowners may often see webs that are close to a porch light or a light source like on the angles of window frames or under eaves of the porch. This is because light will most likely attract other insects which will ultimately become their prey.

How to Get Rid of House Spiders

To kill house spiders inside the house, the most effective method of control is to remove their web and remove egg sacs with a vacuum and to maintain sanitation. This sort of mechanical control, as well as chemical control, will discourage infestations of house spiders. Such methods as chemical control and exclusion will also prevent future infestations. Moreover, chemical control and exclusion methods such as sealing cracks and crevices that lead to the inside of the structure will prevent other insects from entering the premises which ultimately means that there will no longer be an adequate food source for the house spiders.

Chemical control methods include creating barriers around the house with a residual insecticide that is long lasting like wet-able powder formulations or micro-encapsulated formulas. Create barriers around the structure of the house that go 4 feet up from the base of the structure and 4 feet out. Homeowners may also want to focus on spraying the window frames, door frames, or any checking for any utility pipes that lead to the inside of the structure. Homeowners can also spray residual insecticides indoors on window frames and door frames.

All product labels should be thoroughly reviewed before application of any insecticides.