What kind of spider is that?
Don't be a Miss Muffet. Smash the myths and learn the truth about the most common arachnids on the planet.
Fri, Apr 19, 2013 at 05:02 PM
Remember the character in the nursery rhyme?
Little Miss Muffet sat on a tuffet
Eating her curds and whey,
Along came a spider,
Who sat down beside her
And frightened Miss Muffet away.
If the sight of a spider creeps you out and makes you want to run, you are not alone.
Arachnophobia, the fear of arachnids such as spiders, is one of the world’s most common phobias. Not surprisingly, this widespread fear has led to numerous myths about spiders.
- They are insects.
- You can always tell a spider because it has eight legs.
- Daddy longlegs has the world’s worst venom but it can’t bite you.
None of those are true, Rod Crawford writes on his Spider Myth website. Crawford is curator of arachnids at the Burke Museum of Natural History and Culture on the University of Washington campus in Seattle.
“The most prevalent myth — if you didn’t see what bit you, it must have been a spider — is actually dangerous,” he said when asked what’s the biggest spider untruth he’s ever heard. “Only a small amount of mysterious skin lesions come from a bite.”
People have died from being treated for what they believed was a spider bite when in fact they had a much more serious condition, he said. “While it’s true any spider can bite, it’s also true that spiders will go out of their way not to bite.” Spiders typically bite humans when they are trapped in clothing and are trying to defend themselves, he added.
To help you separate fact from fiction and avoid buying into one of the many urban legends about spiders, here is an overview of some of the most commonly asked-about spiders in the United States.
Brown recluse spider
Genus/species: Loxosceles reclusa. The name refers to the spider’s color and habits. It is a reclusive spider that seeks and prefers seclusion and is almost never seen in open areas.
Description: Spiders in this group are called "fiddleback" or "violin" spiders because of the violin-shaped marking on the top surface of the cephalothorax (fused head and thorax). This feature can be very faint depending on the species or how recently the spider molted. Adults have a leg span about the size of a quarter. Their body is about 3/8 inches long and about 3/16 inches wide. The “fiddle” does not serve to identify the spider, Crawford said.
Habitat: The brown recluse spider is found exclusively in part or all of 15 states in the central Midwest southward to the Gulf of Mexico. They thrive in human-altered environments indoors or outdoors, generally in dark, undisturbed sites. In favorable habitats, populations are usually dense. Indoors, they inhabit attics, basements, crawl spaces, cellars, closets and ductwork or registers. They may seek shelter in storage boxes, shoes, clothing, folded linens and behind furniture. Outdoors, they may be found underneath logs, loose stones, in rock piles and in stacks of lumber. They also may be found in barns, storage sheds and garages.
Bites: No fatality has ever been proven by a brown recluse spider specimen, and bites are rare, Crawford said. Bites can result in a painful, deep wound that takes a long time — 6 to 8 weeks — to heal. Young children, the elderly and those in poor physical condition are at greatest risk. When there is a severe reaction, the site can erupt into a "volcano lesion" (a hole in the flesh due to damaged, gangrenous tissue). The open wound may range from the size of an adult's thumbnail to the span of a hand. The dead tissue gradually sloughs away, exposing underlying tissues. Scarring may remain, although about half of brown recluse bites have little or no effect, Crawford said.
First aid: If bitten, remain calm and immediately seek medical attention. Apply an ice pack directly to the bite area to relieve swelling and pain. Collect the spider (even a mangled specimen has diagnostic value), if possible. It is difficult for a physician to accurately diagnose a "brown recluse bite" based simply on wound characteristics. It is absolutely necessary to have the spider for a positive identification. No preservative is necessary, but rubbing alcohol helps to preserve the spider. An effective commercial antivenin is not available.
What you should know: The brown recluse spider is not aggressive, and it normally bites only when crushed, handled or disturbed. Some people have been bitten after accidentally touching the spider when cleaning storage areas. Some bites occur when people put on seldom used clothing or shoes inhabited by a brown recluse.
Genus/species: There are more than 2,000 species of wolf spiders.
Description: Wolf spiders are hairy spiders that can range up to two inches in length. They are usually patterned with a mixture of black, gray, and brown with various markings or lines. Wolf spider mothers carry their large egg sacs around with them. When the young spiderlings hatch, they climb onto their mother's back and ride around until able to hunt on their own.
Habitat: Wolf spiders can be found in a wide range of outdoor habitats, both coastal and inland, wherever there are insects for food. Habitats include shrubby areas, woodlands, wet coastal forests, alpine meadows and suburban gardens. They are not house spiders and do not spin a web, but hide in places such as burrows, under rocks and among leaves during the day and roam at night to hunt for food.
Bites: Wolf spiders are venomous and will bite to defend themselves if handled. The bite may cause a reaction in individuals who are allergic to the venom, though such reactions are reportedly rare.
What you should know: These spiders benefit humans by feeding on a wide variety of insects. When days and nights turn cooler, they are commonly found around doors, windows, houseplants, basements, garages and in almost all terrestrial habitats. Wolf spiders are often confused with the brown recluse, but they lack the violin-shaped marking behind the head. Wolf spiders are best identified by the shape of their eyes, said Crawford. (See the link at the end of this article under “Final words of advice” for a close-up photo of wolf spider eyes.) Wolf spiders are shy and seek to run away when disturbed. If one accidentally wanders indoors by mistake, "herd" the spider into a container with a stick or a pencil and release it outdoors. However, be aware that 95 percent of the spiders that people find indoors and think are wolf spiders, aren't wolf spiders, according to Crawford.
Black widow spider
Genus/species: There are five species of widow spiders in the United States, of which only three are black and called black widow.
Description: The female black widow is normally shiny black with a red hourglass marking on the underside of its globular abdomen. The abdominal marking may range in color from yellowish orange to red and its shape may range from an hourglass to a dot. The body of adult females is about 1/2 inch long. Males are smaller and lighter in color than females. They have a red or pale brown stripe down the middle of their backs from which white or yellow streaks radiate.
Habitat: Three black widow species (L. mactans, L. variolus, L. hesperus) can be found in some part of all the lower 48 states. They are least common in northern forest areas with high rainfall. The black widow inhabits sheltered, dimly lit places such as barns, garages, basements, outdoor toilets, hollow stumps, rodent holes and trash. Black widows occasionally seek dry, sheltered sites such as buildings during cold weather.
Bites: The bite feels like a pin prick but causes pain within a few minutes. The pain spreads rapidly to arms, legs, chest, back and abdomen. Chills, vomiting, difficult respiration, profuse perspiration, delirium, partial paralysis, violent abdominal cramps and spasms may occur within a few hours. The victim usually recovers in two to five days.
First aid: Clean the bite area with soap and water. Apply ice to the bite area to slow absorption of the venom. Elevate and immobilize the extremity. Capture the spider, if at all possible, for identification purposes. Seek medical attention immediately. People with heart conditions may need hospitalization.
What you should know: The spider’s name comes from the belief that the female kills the male after mating. Crawford, though, says this is a myth. The female usually only bites people when its web is disturbed. While the female black widow possesses a venom 15 times more potent than rattlesnake venom, it has only 1/1000th as much venom as a rattlesnake, according to Crawford. With improvements in treatment, there have been no deaths from black widow bites in the United States since the 1960s, Crawford said. Males do not bite. To reduce the chance of being bitten, wear a long-sleeved shirt, hat, gloves and boots when handling boxes, firewood, lumber and rocks. Inspect and shake out clothing and shoes before getting dressed.
Photo: bob in swamp/Flickr
Genus/species: There are about 4,000 species in 168 genera worldwide. This is the third largest family of spiders.
Description: Many orb weavers are brightly colored and have hairy or spiny legs. Large distinctive webs of concentric circles, sometimes several feet across, are the best indication of the presence of an orb weaver spider. Most orb weavers appear in spring but are not noticed until they start building their large webs in the late summer or early fall. These are docile, non-aggressive spiders that generally will flee at the first sign of a threat.
Habitat: Orb weaver spiders are prolific throughout the entire United States. They build their large nests any place where there is abundant prey and a structure to support the web — around outdoor light fixtures, tree branches, tall grasses and bushes. Many orb weavers build a new web each day. Generally, toward evening or morning depending on the species, the spider will consume the old web, rest for about an hour, then spin a new web in the same general location.
Bites: Bites from an orb weaver are very uncommon. Typically, they will only bite if they feel threatened and trapped without a chance for escape, if someone tries to pick them up, for example. A bite is often compared to a bee sting, at the very worst. For most people, this is nothing serious. Symptoms are usually negligible or there is mild local pain, numbness and swelling with redness. Occasionally nausea and dizziness can occur after a bite.
First aid: Disinfect the bite, as with any puncture. If there is pain, it should go away within 24 hours. Seek medical attention if the pain persists.
What you should know: Orb weavers are not dangerous to people and pets. In fact, they are actually quite beneficial because they will catch and eat a lot of pest-type insects. The famous spider from "Charlotte's Web" is a barn orb-weaver spider, Araneus cavaticus. Orb weaving spiders produce the type of flat, ornate, circular web that many people often associate with spiders.
There are many, many species of spiders that inhabit gardens throughout the United States. One of the things that may prompt people to search online for information about a “garden spider” is because they’ve walked unsuspectingly into a large sticky web that seemed to have sprung up overnight from nowhere. In a sense, it did. Most likely, the spider in question is the black and yellow Argiope (Argiope aurantia), one of the species of orb weavers.
Final words of advice: “Eyes, not ‘markings,’ are how those in the know distinguish major groups of spiders,” Crawford said. He suggested the websites listed below as helpful in identifying some of the spiders mentioned above:
Should you have a confirmed spider bite, it is important to disinfect the bite site, Crawford said. “Any puncture can become infected by something far worse than any spider venom,” he advised.
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