Snakes, bats, and spiders conjure images for many of foreboding creatures and places. In most cases you would be hard-pressed to find any snakes or bats in and around your home. However, a quick search outside your door or a few room corners inside and you may easily find a spider or two. Fortunately, as with snakes and bats, almost all the spiders we encounter on a day-to-day basis are completely harmless and are actually beneficial.
Outwardly similar to insects, spiders are not classified as insects, but both belong to the group of animals called arthropods. Insects consist of three distinct body regions—head, thorax, and abdomen. Spiders have only two body regions—cephalothorax and abdomen. The most familiar difference between spiders and insects is the leg count. Insects possess six legs in three pairs while spiders have eight legs in four pairs. In addition to eight legs, spiders usually possess four pairs of eyes though some may have only three pair. In some cave-dwelling spiders, eyes are absent.
Species wise, spiders are not as successful as the insects, which contain over 900,000 known species. Worldwide there are some 40,000 spider species with around 3,500 species in the United States. In Alabama the number of spider species is approximately 700, with more spiders likely to be discovered with future research and surveys.
Spiders are perhaps most famous for their ability to produce silk. Silk is produced by glands located in the abdomen. Liquid silk is secreted through the spinnerets and solidifies quickly as the spider uses its legs to draw the silk out into threads. A single spider may have six silk glands, each producing different types of silk. One type of silk may be used to build the egg sac, with other types used in different aspects of web construction.
Not all spiders build webs. Trapdoor spiders lie in wait inside their silk-lined burrows. Wolf spiders actively roam the ground in search of prey, and jumping spiders trail a silken anchor line as they hop along. Another use of silk allows young spiders to “fly.” Long threads of silk catch the wind and transport young spiders across the sky in a process called ballooning.
Everyone has surely encountered one spider that regularly shares our homes. Even the most well-kept and tidy house likely has a few common house spiders present. These harmless spiders, less than 1/2-inch, build their webs in seldom-disturbed corners of rooms and window sills. They go mostly unnoticed until their sticky webs collect dust or the carcasses of insects they entrap and consume. Only the most rigorous dusting and vacuuming schedule is able to eliminate this spider from our midst.
Another very common spider in and around dwellings in the southeastern United States is the southern house spider. This spider is responsible for the familiar cobwebs that are found in attics and in sheds and barns. The intimidating appearance of a female southern house spider may be quite unnerving to some. Females are about 1 inch in length and are generally grey to black in color and are covered in fine hairs. As with many spiders, the male is much smaller. A male southern house spider is light brown and about half the size of the female.
While all spiders have venom, only three species in Alabama pose any real danger to people. One is the brown recluse. A fitting name, the brown recluse spider is found in generally darkened, undisturbed areas under rocks, logs or other debris. Recluse spiders may also occupy human dwellings but are likely found in attics or undisturbed recesses of closets. This spider reaches a body length of 3/8-inch and the slender legs span the size of a quarter. Brown recluse spiders are also known as fiddle-back spiders for the dark violin patterns on their backs. Easily confused with other brown-colored spiders, especially the male southern house spider, a brown recluse under close and magnified observation reveals only six eyes in three pairs. The bite of this spider may be of no consequence to some individuals while others may develop painful swelling and an area of tissue death that may take weeks to heal. All bites by brown recluse spiders should be taken seriously and medical attention should be sought.
Perhaps no spider is feared more than the black widow. Ironically, this spider is related to the common house spider and similar body shapes hint at this relationship. Adult females are shiny black with characteristic red hourglass markings on the underside of the abdomen. Body length is about 1/2-inch with legs reaching about 1 1/2 inches. Males are half the size of females and on occasion are killed and consumed by females after mating, thus giving the spider its common name.
Black widows are almost never found inside dwellings. A typical location for the black widow’s tangled web is a sheltered, undisturbed area behind a shed or garage. Black widows possess potent venom and a bite from the spider should always be considered serious though it is rarely life-threatening. Always seek prompt medical attention if bitten.
Also in Alabama is found the brown widow. Found in similar habitats, the brown widow is smaller than the black widow. Adult females are generally grayish to brownish, and the abdomen and legs appear striped. A bold orange-colored pattern is evident on the underside. As with the black widow, the bite of a brown widow should be taken just as seriously.
A late summer walk in shaded woodlands, swamps, or even around your house may be interrupted by an unwelcomed encounter with the enormous web of the golden silk spider. Also known as the banana spider, this large mostly yellow inch-long bodied spider constructs a web that may reach 3 feet across with anchor lines stretching even further. The tiny male may also be seen in the web as well. Though some find the spider fearsome in appearance, this is another one of our harmless spiders.
Often underappreciated, spiders are another part of the balanced natural world around us. They consume countless insects and are important prey items for birds, lizards and a host of other animals. Only a few spiders are potentially dangerous while the rest may only inconvenience us with a little extra housework. If interested, a good source of Alabama spider information is the book, “Spiders of the Eastern United States: A Photographic Guide” by Dr. Mike Howell and the late Dr. Ronald Jenkins from Samford University.
For additional information contact Roger Clay, Alabama Division of Wildlife and Freshwater Fisheries, 30571 Five Rivers Blvd., Spanish Fort, AL 36527.
The Alabama Department of Conservation and Natural Resources promotes wise stewardship, management and enjoyment of Alabama’s natural resources through five divisions: Marine Police, Marine Resources, State Lands, State Parks, and Wildlife and Freshwater Fisheries. To learn more about ADCNR visit www.outdooralabama.com.