Oklahoma is home to numerous kinds of spiders, including tarantulas, orb weavers, jumping spiders and wolf spiders. Although some of them may startle you as you work in your garden, these efficient predators play a vital role in the ecosystem. Only two kinds of spiders in the state are of medical concern: the brown recluse (Loxosceles reclusa) and black widow (Latrodectus spp.).
Orb weavers spin geometric webs and rely on the webs' sticky strands of silk to catch their prey -- typically flying insects. This is one of the largest families of spiders with over 3,000 known species. Some spin webs throughout a garden while others do so in locations closer to a home and outdoor lights.
Some orb weavers spiders are quite large, including the black and yellow garden spider (Argiope aurantia), which is also known as the writing spider and black and yellow argiope. A female can reach over 1 inch long, not including its legs, and the species' webs can have a diameter over 2 feet. A black and yellow garden spider has a long, egg-shaped abdomen with black and yellow markings; its head and midsection has fine, silver hairs. Despite the female's formidable size, the black and yellow garden spider is reluctant to bite unless someone comes too close to its egg sac.
Fast, large and hairy are three terms that often describe one of the Oklahoma's most common group of spiders: wolf spiders. Thousands of wolf spider species exist, making its spider family among the largest. Wolf spiders tend to be nocturnal, although you may come across one in the garden when overturning rocks, logs or plants, disturbing the spider's daytime refuge. Unlike orb weavers, which rely on webs to snare prey, wolf spiders are active hunters.
Wolf spiders vary greatly in size, from about 1/10 to 1 1/5 inch in body length. Most are gray, brown or dark with stripes or other markings. Wolf spider females show great maternal care: Each one attaches its egg sac to its spinnerets until the egg sac hatches, and then the female carries the spiderlings on her back until they are large enough to fend for themselves.
One of numerous Oklahoma wolf spider species is the rabid wolf spider (Rabidosa rabida). This spider is yellowish brown with dark stripes running lengthwise. A female can grow nearly 1 inch long, not including legs.
Jumping spiders make up the largest of all spider families, with over 5,000 species. These hunting spiders have the best eyesight of all spiders and are able to jump or spring great distances to pounce on their prey.
Several jumping spider species inhabit Oklahoma, including the bold jumping spider (Phidippus audax), which is also called the daring jumping spider. Its body length can become about 3/4 inch. This species is often rich black and hairy. Noticeable white markings appear on the abdomen while the mouth parts, on which the fangs are located, are metallic green. Gardeners may see this spider on tree trunks, deck railings or on the ground; it often makes its way into houses as well.
The largest spiders in Oklahoma are tarantulas, notably the Oklahoma brown tarantula (Aphonopelma hentzi), also called the Texas brown tarantula. Females are larger than males and can reach 2 inches in body length with a leg span of about 6 inches. Adults are brown or black with stout, hairy bodies.
The females hunt primarily at night and spend the day in burrows; males looking for mates may be seen during the day. Gardeners are most likely to see tarantulas during June and September. Despite a tarantula's large size and powerful fangs, its bite is comparable to a bee sting, according to Oklahoma State University.
Medically Significant Species
The two medically significant spider species in Oklahoma have very different appearances and habitat preferences. The black widow female has a shiny, round and black body with red markings; it may have a red hourglass shape on the underside of its globelike abdomen. With legs extended, the female can reach 1 1/2 inches long. A male is about 1 inch long and black; it may have light stripes on its abdomen.
Female black widow spiders tend to build their webs outdoors and low to the ground in protected areas. Around spigots, under patio furniture or in outbuildings are common locations for webs.
The bite of a black widow spider can cause serious effects due to the neurotoxin in the venom. Symptoms include severe pain spreading from the bite wound to the arms, legs, chest, back and abdomen. Abdominal cramping, nausea, partial paralysis and delirium are also effects.
The brown recluse, also called the fiddleback spider, is most often nocturnal and, true to its common name, is reclusive in nature, usually hiding during the day. Although these spiders are common indoors -- nearly every home in Oklahoma has them, they also have outdoor habitats. Gardeners may come across them when overturning logs, bark or rocks. These spiders are also found in outbuildings.
A brown recluse typically reaches about 1/2 inch long, not including legs. It is light tan to dark brown and usually has a darker violin-shaped marking extending from just between and behind its eyes to part way down its back.
About 25 percent of brown recluse bite victims show serious symptoms. The spider's venom produces a sore that becomes necrotic, meaning the tissue around the wound dies, which can result in a craterlike wound.