Common Black Semi-Large House Spiders

Most spiders are harmless to humans.

Many people cringe at the sight of spiders inside their home. However, spiders are often beneficial predators that feed on pests in your home and garden. Most spiders are not harmful to humans and only bite when trapped or threatened. There are a variety of common black house spiders that are fairly large, such as the wolf spider.

Identification

Spiders are not insects, but arthropods. Insects have six legs, while spiders have eight legs. Spiders feed on insects and other arthropods, keeping them under control. Spiders have two main parts of the body, the abdomen and head, as well as eight legs. Six to eight eyes are scattered across the spider's head and all have fangs that inject venom into their prey. Spiders produce silk that they use to spin their webs which are primarily used to catch prey.

Life Cycle

Spiders lay eggs that are carried by the female spider or placed in their web. Some spiders attach their egg sacs to hard surfaces in homes or garages. Most female spiders lay hundreds of eggs at once. After hatching, most young spiders are miniature versions of their parents, except their coloring may darken as they age. Silk is produced by all spiders and is used to spin webs to capture prey and make egg sacs. Spiders also produce venom that is used to feed on their prey. Insects and mites are typical spider food. A variety of methods are used to capture their prey, depending on the species of spider. Some will lie in wait for their prey, while others construct webs to snare it. Spiders have a special enzyme in their saliva to keep them from getting stuck in their own webs.

Types

There are a variety of black house spiders that are fairly large and live inside homes. These spiders can reach up to 1 3/8 inches in length. Wolf spiders are often black, gray or brown and carry their young on their backs. Wolf spiders are not harmful to humans, but can be frightening to look at because of their size.

The black widow often builds its web indoors and is often found under window sills or in the corners of rooms. Black widows are black and have a red hourglass on their abdomen. This is a species of spider that is dangerous to humans and those bitten should seek medical attention quickly.

Funnel weave spiders are another common house spider that is semi-large and black, brown or gray. These spiders are known for their intricate, funnel shaped webs that they build close to the ground. Funnel weave spiders hide in their web and ambushes its prey once it comes close. These spiders are very quick and agile.

Considerations

Although most spiders are not venomous to humans, it is unpleasant to be bitten. Preventing spider bites is best accomplished by shaking out your shoes before putting them on and inspecting your towels and bedding before using them. Avoid storing boxes under your bed, as this gives spiders a place to hide. Most spiders prefer dark, damp places to construct their webs. Keep spiders out of your home by placing tight fitting screens in your windows, caulking cracks in walls and removing plant debris around your home. Placing a yellow bulb in your porch light will attract fewer insects and forces spiders to look elsewhere for food.

References

• Colorado State University: Spiders In The Home; F.B Peairs; W.S Cranshaw; P.E Cushing; December 2008
• Ohio State University: Spiders in And Around The House; Susan C. Jones
• University of Kentucky: Funnel Weavers & Grass Spiders Of Kentucky