Spiders in the Home

Spider Control: Protect Your Home

Facts

Description

Over 40,000 species of spiders exist around the world, with more than 3,000 found in the United States alone. Due to their numbers and diversity, spiders resist traditional classification. Spiders can be identified down to the family level fairly easily by pest management professionals; however, it takes a trained taxonomist to identify them down to species. To make pest control easier, professionals organize spiders into one of four broad categories: burrowers, web-spinners, active hunters, and sit-and-wait ambushers. Over 20 species of web-spinners and active hunters are potential pests to North American homeowners and residents.

Scientific Classification: Various scientific names

Class	Order	Family
Arachnida	Araneae	Various

Appearance

What Do They Look Like?

Size: Due to the sheer variety of species, spiders tend to resist generalizations about appearance. Spiders may remain as small as 1/5 of an inch (5.08 mm) or grow as large as an inch (25.4 mm) or more in length. Perhaps the only universal rule of spider size is that females are significantly larger than males.

Color: Spiders range in color from black to white. Rarely solid in color, the pests tend to have different colored markings along their legs, abdomen, and cephalothorax. Frequently, spiders appear brown with darker brown patterns, black with white markings, yellow and black, reddish brown, and so forth.

Characteristics: All spiders have two main body sections: the abdomen and the cephalothorax. Each spider also possesses eight legs, which protrude from the body. Additionally, all spiders have mouthparts; chelicerae, or pincer-like appendages; eight eyes, which are arranged in various ways that can be used as a means of family identification; fangs and venom glands; and spinnerets, which are the silk-spinning organs of spiders.

Geographic Range

Spiders have the capacity to survive in most environments on the planet. They are found on every continent and even dwell in shallow freshwater. Extreme cold is the only environmental element spiders cannot withstand.

Food

What Do They Eat?

Spiders are considered predators. Their diet consists of insects, other spiders, and various invertebrates. Some especially large species will attack smaller vertebrates, such as lizards and frogs. Though people often find the arachnids unnerving, spiders remain beneficial to humans because of what they eat. Various outdoor pests serve as a staple in a spider’s diet, therefore, potentially reducing the number of pest we encounter.

Biology

The various species of spiders each have unique reproduction habits and lifespans, though some consistencies exist. Typically, female spiders live longer than males. Lifespans range anywhere from several months to as long as seven years. Spiders tend to mate between late spring and mid-summer. Females deposit eggs in sacs or cocoons and produce anywhere from 30 to over 1,000 eggs at a time, depending on the species. Many species require several rounds of molting before reaching maturity.

Detection

Look for spider webs inside and outside the home
May spot adults scampering across the floor
Look for egg sacs and cocoons located near spider webs

Problems Caused by Spiders

While spiders actually do more good than harm to homeowners, some species are venomous, though most lack strong enough “jaws,” or chelicerae, to puncture the layers of human skin necessary to cause serious damage. Nevertheless, many people suffer from arachnophobia, and the presence of spider webs carries a stigma of uncleanliness. As such, pest management specialists often respond to the need for elimination.

Signs of Infestation

Typically, spiders do not congregate in large numbers, which makes infestations a rare occurrence. Active hunters and web-spinners are the two types of spiders most commonly found in the United States, where they enter homes to search for food. As a result, homeowners may spot webs inside and outside the house in gardens, woodpiles, attics, and basements. Residents may also find adult spiders climbing on walls or running across the floor in search of insects.

Finally, some species of web-spinners and active hunters will leave egg sacs and cocoons inside the home. As spiders tend to produce hundreds of eggs at a time, the sacs and cocoons generally suggest the presence of a large population of the arachnids in the home.

Prevention Tips

As spiders rarely enter homes in the first place, homeowners need only heed simple preventative measures. Controlling the level of humidity in attics, basements, and other dark areas of the home deters spiders from settling. Sealing or caulking points of entry, like cracks in the foundation or around doors and windows, helps deter their ability to get inside. Cleaning up woodpiles and other attractive hiding places outside further reduces the chances of finding spiders in or near the home. Lastly, removing outside webs and changing outdoor lighting reduces the availability of prey, which compels spiders to look elsewhere for food.

Tips for Removal from Home

If spiders have already moved in, homeowners have a few options for removal. Vacuuming, for example, is an effective means of elimination. Adult spiders, eggs, and webs can all be vacuumed up, and the dust inside vacuum bags quickly suffocates adults. As unnerving as people may find the prospect, capturing and releasing spiders outside the home is also an effective method of sending the pests on their way. As a last resort, people may turn to insecticides or pesticides. Homeowners who have reached the need for chemicals, or who suffer from black widow or brown recluse spider infestations, should contact a licensed pest control specialist.

Spiders are sometimes called “scary insects” but spiders are not insects. To be a true insect, entomologically speaking, the specimen must have six legs and three body segments: head, thorax, and abdomen. Spiders have two body segments and eight legs.

Spiders are some of the most interesting animals known. They are typically hunters but they can be passive hunters or active hunters. Passive hunters will spin a web and catch prey in the web. Webbing is a scientific marvel since the web is spun and is very strong as well as adhesive. Spiders sense prey by vibration of the web. When prey is caught, the spider will approach the quarry and will inject the prey with venom to render the prey helpless. The spider will then consume the prey.

Active hunters will literally attack prey. This can be done by jumping onto prey as is common for the “jumping spiders.” They will then render the prey helpless and consume it. There are also spiders which capture prey by waiting for the prey and trapping the prey or attacking. The trap door spider sets a trap for the prey.

Virtually all spiders are venomous, but few spiders are harmful to humans. Yet, many people fear spiders and surveys have shown that spiders are more feared than many other real threats.

Of the spiders known to be harmful to humans in North America, the Black Widow and the Brown Recluse spiders are the most dangerous. The Black Widow can bite humans and such bites require medical attention, although, the bites are rarely fatal, contrary to popular belief. The Brown Recluse spider is found mostly in the south central areas such as Tennessee, but this spider can be moved to other areas. While the bites are rare, the spider bite can cause abscesses which may require surgery.

Proper spider identification is important when dealing with spiders and knowing how to control the spiders is vital.

Resources:
Spiders images courtesy of Univ of Nebraska