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Spiders and Spider Bites

There are at least 50,000 spider species in the arachnid family. Spiders are defined as having eight jointed legs, no wings, no antennae and only two body sections: the thorax and the abdomen. Spiders spend their entire life span capturing and eating other insects (about 2,000 in a year). Even though spiders do a great deal of good for our environment, spiders are greatly feared by most of the population. Most spiders are killed only because they scare people, not because they are actually dangerous to humans.

All spiders have some amount of venom with varying degrees of potency. The fangs of a spider are hollow. The venom is injected through the fangs into the victim (usually an insect). The venom will rapidly paralyze the victim and aid in digestion. Fortunately, most spiders are not dangerous to humans because their fangs are either too short or too fragile to penetrate human skin.

Spiders do not attack in herds. Spiders do not lay in wait and attack people. Spiders do not lift the covers at night and crawl into bed to bite people as they are sleeping. Some spiders can jump but they are not intentionally jumping at humans to attack them. A spider generally bites a human because it was scared and bites to defend itself. Spiders generally prefer to live in undisturbed areas such as corners of the house or the eaves or in the garden where they can catch insects in peace.

Killing spiders with pesticides is difficult. Spraying surfaces is usually ineffective because the spider has minimal contact with the sprayed area. The actual spider or egg sacs must be sprayed with pesticide. The danger of a possible spider bite has to be weighed against the risk of over-using pesticides that probably will not work against spiders.

Bite marks from most spiders are usually too small to easily be seen. Frequently the patient will not recall being bitten. Many of the spider bites will result in pain, small puncture wounds, redness, itching and swelling that lasts a couple of days. Spiders rarely bite more than once, so multiple bites are usually caused by insects such as fleas, bedbugs, ticks, mites and biting flies.

Spider Bites

Unlike mosquitoes, spiders do not seek people in order to bite them. Generally, a spider doesn't try to bite a person unless it has been squeezed, lain on, or similarly provoked to defend itself. Moreover, the jaws of most spiders are so small that the fangs cannot penetrate the skin of an adult person. Sometimes when a spider is disturbed in its web, it may bite instinctively because it mistakenly senses that an insect has been caught.

The severity of a spider bite depends on factors such as the kind of spider, the amount of venom injected, and the age and health of the person bitten. A spider bite might cause no reaction at all, or it might result in varying amounts of itching, redness, stiffness, swelling, and pain--at worst, usually no more severe than a bee sting. Typically the symptoms persist from a few minutes to a few hours. Like reactions to bee stings, however, people vary in their responses to spider bites, so if the bite of any spider causes an unusual or severe reaction, such as increasing pain or extreme swelling, contact a physician, hospital, or Poison Control Center (in California, the number is 1-800-876-4766 or 1-800-8-POISON).

Sometimes a person may not be aware of having been bitten until pain and other symptoms begin to develop. Other species of arthropods whose bites or stings may be mistaken for that of a spider include ticks, fleas, bees, wasps, bedbugs, mosquitoes, the conenose (kissing) bug (Triatoma protracta), deer flies, horse flies, and water bugs (Lethocerus spp.).

For first aid treatment of a spider bite, wash the bite, apply an antiseptic to prevent infection, and use ice or ice water to reduce swelling and discomfort. If you receive a bite that causes an unusual or severe reaction, contact a physician. If you catch the critter in the act, capture it for identification, preserve it (or whatever parts of it remain), and take it to your county UC Cooperative Extension office. If no one there can identify it, ask that it be forwarded to a qualified arachnologist.

Black widow spider

Black widow spiders generally live in trash, closets, attics, woodpiles, garages and other dark places. They are found throughout California, especially in the warmer regions such as the Central Valley and Southern California. Only the female spider is dangerous to humans.

What does a black widow spider look like?
The black widow spider is a shiny, inky black spider with a large round tail segment (abdomen). Including its legs, the black widow generally measures from one-half inch to one inch in length. Red to orange-colored markings, usually in the shape of an hourglass, are found on the underside of the belly.

What are the symptoms of a bite?
A black widow spider bite gives the appearance of a target, with a pale area surrounded by a red ring. Severe muscle pain and cramps may develop in the first two hours. Severe cramps are usually first felt in the back, shoulders, abdomen and thighs. Other symptoms include weakness, sweating, headache, anxiety, itching, nausea, vomiting, difficult breathing and increased blood pressure. Young children, the elderly and those with high blood pressure are at highest risk of developing symptoms from a black widow spider bite.

How dangerous are black widow spider bites?
If a black widow spider bites a person, do not panic! No one in the United States has died from a black widow spider bite in over 10 years. Very often the black widow will not inject any venom into the bite and no serious symptoms develop. Wash the wound well with soap and water to help prevent infection.

If muscle cramps develop, take the patient to the nearest hospital. Some victims, especially young children, may be admitted overnight for observation and treatment. There is treatment for a black widow spider bite that can take care of the symptoms. Various medications are used to treat the muscle cramps, spasms and pain of a bite. Black widow spider antivenin is seldom necessary.

Brown recluse spider

Brown Recluse Spider What does a brown recluse spider look like?
Named for its habit of hiding in dark corners, the brown recluse spider (Loxosceles reclusa) is also known as the violin spider or fiddleback spider because of a violin-shaped marking. The brown recluse spider is about a half-inch long (including legs) and is a solid light brown color. The violin marking is configured with the base of the violin beginning at the eyes and the neck of the violin pointing toward the "waist." The violin marking is difficult to see clearly. Two other features can help identify the brown recluse: it has six eyes rather than the typical eight and the tail-end segment has no markings. If you see a brown spider with markings on the tail end, it cannot be a brown recluse spider. Any markings, patterns or spots on the tail end of a spider immediately eliminates the possibility that it is a brown recluse spider. It is, instead, one of dozens of brown spiders that live in houses and yards. They may bite, but they are not dangerous.

Where do brown recluse spiders live?
Spider experts across the state agree that the true brown recluse spider does NOT live in California, but is native to Kansas, Texas, Oklahoma and Mississippi. There are some related species found in California. The Loxosceles laeta, imported from South America, has been found in eastern Los Angeles County. The Loxosceles deserta is found in the Mojave and Sonoran deserts, the foothills of the Central Valley up to Merced and Fresno counties, but not in Northern California.

In any case, the brown recluse is called a "recluse" because it hides and is not commonly found out in the open. The brown recluse will hide in dark, quiet, out-of-the-way areas where it will not easily be disturbed.

What are the symptoms of a brown recluse spider bite?
The brown recluse spider bite usually causes some pain or burning in the first 10 minutes, accompanied by itching. The wound takes on a bull's-eye appearance, with a center blister surrounded by an angry-looking red ring and then a blanched (white) ring. The blister breaks open, leaving an ulcer that scabs over. The ulcer can enlarge and involve underlying skin and muscle tissue. Pain may be severe. A generalized red, itchy rash usually appears in the first 24-48 hours. Other symptoms include fever, chills, nausea, vomiting, muscle aches and hemolytic anemia (a condition where the red blood cells are destroyed).

People bitten by an unseen spider sometimes blame the brown recluse spider because their bite resembles a brown recluse spider bite. However, there are a number of other spiders and insects, as well as other medical conditions, that are capable of producing tissue wounds of similar appearance, but these are usually of a lesser severity.

What is the treatment for a brown recluse spider bite?
Treatment consists of washing the wound and applying an antibiotic ointment. The victim should seek medical attention if there are signs of an infection, an ulcer that does not heal, a bite accompanied by nausea, vomiting, fever or a rash. There is no special treatment or medication used to treat a brown recluse spider bite. If infection develops, antibiotics are used. If a wound becomes deep and infected, occasionally surgery is needed. Anytime there is a bite or a wound that is not healing and getting worse, see a physician for evaluation.

More Information on Brown Recluse Spiders
Listed Below

Chronic arachnidism
or necrotic arachnidism

While most spider bites are not dangerous, there is a group of spiders that can produce bite wounds that look similar to a brown recluse spider bite. Unless the spider was actually seen, captured and brought to the physician, the brown recluse spider is not likely to be the culprit. Some of the spiders in this group that can cause a nasty bite include the running spider, jumping spider, wolf spider, tarantula, sac spider, orbweaver spider and the northwestern brown spider, also known as the hobo spider.

What are the symptoms of a bite from these kinds of spiders?
In most cases of bites from these spiders, there is pain or burning at the bite site in the first 10 minutes. The bite from this group is usually described as looking like a "target" or "bull's-eye." The center of the wound is usually a blister surrounded by a reddened area. A pale or blanched area may surround the discolored reddened area. The blister may rupture, leaving an open ulcer. In severe cases the ulcer can become deep and infected causing tissue breakdown or tissue death (necrosis).

Kissing Bug Worsening pain, itching and a burning sensation develop. A patient may also have symptoms such as a red, itchy rash over the torso, arms and legs that is usually seen in the first 24-72 hours. Patients may have pain in the muscles and joints, fever, chills, swollen lymph nodes, headaches, and nausea and vomiting.

How are these bites treated?
Frequently, when people with spider bites call the Poison Center, they think there is some special treatment that is necessary for their bite. There is no specialized therapy other than treating the symptoms. Most importantly, keep the wound clean to prevent infection. If the wound does not heal or does develop an infection, see your physician. Do not wait days and weeks while the wound continues to get worse.

There are tales of people having limbs amputated after spider bites. These involve people who refused to see a physician even though they had massive wounds that did not heal and became grossly infected. A wound that may have been originally treated with simple oral antibiotics, but left untreated, may require surgical intervention in extreme cases.

What else can cause a nasty looking wound?
Kissing bugs, fleas, bed bugs, flies, mites, wasps, ants and blister beetles have produced lesions similar to a brown recluse spider bite. Many skin disorders and medical conditions can produce lesions that can also mimic a brown recluse spider bite. Some of these include infected herpes outbreaks, bedsores, diabetic ulcers, poison oak and Lyme disease. Again, use common sense: If there is a wound that is not healing as expected or getting worse, see a physician.

Jumping spiders

Jumping Spider The jumping spider is probably the most common biting spider in the United States. People are caught by surprise and scared when they see the spider jump, especially if it jumps towards them. Bites from a jumping spider are painful, itchy and cause redness and significant swelling. Other symptoms may include painful muscles and joints, headache, fever, chills, nausea and vomiting. The symptoms usually last about 1-4 days.

Wolf spiders

Wolf spiders are commonly found in California. They are large hairy spiders, up to 3-4 inches across. They are a mottled gray-brown color, which helps them hide in sand, gravel, leaves and other debris. Female wolf spiders carry their young on their backs. Except for one group, wolf spiders do not spin webs. They tend to burrow into the earth and hide. They are aggressive, come after their prey and are fast runners. Because of their impressive size and aggressiveness, wolf spiders can easily incite panic. Wolf Spider

Bites from a wolf spider can cause pain, redness and swelling. The large jaws/fangs can cause a tear in the skin as they bite. Swollen lymph glands may develop. The skin area at the bite may turn black. Swelling and pain can last up to ten days.


Tarantulas are also large hairy spiders. In fact, some people call any large hairy or fuzzy spider a tarantula. Tarantulas are very hairy with sharp bristles. The hairs are easily shed or can be rubbed off. Handling a tarantula can result in irritation to the skin. If hands are not washed after handling a tarantula and eyes are touched, the sharp hairs can cause eye irritation that may require a trip to the physician.

Tarantula Tarantulas are sensitive to vibrations and hunt at night by touch. If cornered, the tarantula will make a purring sound and may rear up on its back legs. Even though tarantulas are scary looking to most people, most bites do not produce any significant poisoning symptoms. However, the bites can be quite painful because of the large size of the spider.

Wash your hands well with soap and water after handling a tarantula.

Northwestern brown spider or the hobo spider

The northwestern brown spider or hobo spider (Tegenaria agretis) is well known in Oregon and Washington and is also quite common in Utah. Spider Hobo Spider bites by this spider are becoming recognized more often in California, which may be due to the fact that the spider is becoming better known. The hobo spider often causes a bite that leaves an open, slow-healing wound. Bites from this spider are frequently and mistakenly thought to be brown recluse spider bites.

Keep the wound clean and prevent infection. If the bite becomes infected or does not seem to heal, see a physician.

Daddy longlegs spiders

The Daddy Longlegs is not a true spider in that it cannot make silk and does not have fangs or venom glands. Daddy Longlegs have long thin legs with flexible claw-like "fingers". Daddy Longlegs can pinch but rarely penetrate human skin.

Daddy longlegs Spider They have scent glands on the front part of their bodies that can give-off a bad-smelling fluid. This stinky fluid is used as a defense mechanism to keep enemies away. Some people might have a reaction to the fluid but Daddy Longlegs are not considered dangerous to humans.

Daddy Longlegs are usually found hanging upside down in corners, eaves or basements. They are very common and are found in most homes. Because they eat insects and other spiders, they are considered beneficial.

Brown Recluse and Other Recluse Spiders

Brown Recluse Spider

If asked to name all the spiders they are familiar with, most Californians would have a short list: tarantula, black widow, and brown recluse. Tarantulas are well known because of their large, intimidating size and their use in many movies as eight-legged villains. Black widows are very common throughout the state, are potentially dangerous, and are easily identifiable by their shiny black body color and red hourglass on the belly. The brown recluse, however, is an enigma: there are no populations of the brown recluse Loxosceles reclusa, in the state and fewer than 10 verified specimens have been collected over several decades in California. Yet people frequently relate stories in which they or someone they know was supposedly bitten by a brown recluse in California. This publication was written in response to the confusion that exists regarding brown recluse spiders in California.


Over the years, the group of spiders to which the brown recluse belongs has been known by various colloquial names: "violin" spiders, "fiddleback" spiders, "recluse" spiders, and "brown" spiders. Recently the American Arachnological Society chose "recluse spiders" as the official common name for this group. The scientific name for the recluse spider group is Loxosceles (lox-SOS-a-leez). All known members of the group have a scientific name, and the more familiar members of this group also have a common name (e.g., brown recluse, desert recluse, Arizona recluse).


The most definitive physical feature of recluse spiders is their eyes: most spiders have eight eyes that typically are arranged in two rows of four but recluse spiders have six equal-sized eyes arranged in three pairs, called dyads. There is a dyad at the front of the cephalothorax (the first main body part to which the legs attach) and another dyad on each side further back.

Many publications refer to the violin on the dorsal surface of the cephalothorax as the most important diagnostic feature. Although this marking is fairly consistent in mature brown recluses and Texan recluses (L. devia), it can vary in intensity and sometimes fades in preservative, and it is very faint to nonexistent in several recluse species found in the southwestern United States (e.g., the desert recluse). Therefore, checking the eye pattern will eliminate almost all suspect recluse spiders from consideration whereas the presence or absence of the violin marking may lead to misidentifications. In addition, the abdomens of all recluses are covered with fine hairs and are uniformly colored, although the coloration can vary from light tan to dark brown, depending on what they have eaten. There is never a coloration pattern on the abdomen. Finally, the legs are similarly covered with fine hairs whereas many nonrecluse spiders have stout spines on their legs.

Some spiders share each of these physical characteristics (six eyes in dyads, dark pattern near the eyes, uniformly colored abdomen with fine hairs, no spines on the legs); however, no nonrecluse spider has all four characteristics. On this basis, more than 99% of the spiders found by Californians can be identified as something other than a recluse spider. If, however, you do find a recluse spider in California, it will most likely be the native desert recluse, L. deserta. To further identify Loxosceles spiders to species requires a high-power microscope and the skills of a spider expert (arachnologist).


Because of the misinformation surrounding the brown recluse's presence in California, many spiders that are virtually harmless are turned in by the public for identification, but most of them are not even from the recluse family. The few Loxosceles spiders that have been turned in for identification were the desert recluse (not the brown recluse) and, not surprisingly, were found in the eastern deserts where they are native. Presented below are descriptions of spiders that share some of the same physical features as the brown recluse and might be misidentified as a recluse spider. For additional information, consult a spider identification book such as Kaston's How to Know the Spiders,

Six-Eyed Spiders

The spitting spiders (Scytodes spp.) are closely related to recluse spiders and have six eyes arranged in a similar pattern. However, they also have many black spots or lines on their bodies that would exclude them as recluses. The Woodlouse spider, Dysdera crocata, has six eyes arranged in two groups of three (triads) and no bodily markings; nonetheless, it is commonly mistaken for a recluse in California and in other parts of the United States.

Spiders with Violin-Shaped or Other Dark Markings

Many common tan or gray spiders have dark markings on the head region, which convinces people that they have caught a bona fide recluse spider. These spiders include cellar spiders (Psilochorus spp., Physocyclus spp.), pirate spiders (Mimetus spp.), and sheet web spiders (Linyphiidae). The marbled cellar spider, Holocnemus pluchei, also confuses people even though the dark marks are on the ventral (underside) not the dorsal (top) surface of the body.

Ubiquitous Brown Spiders

Virtually every spider that is tan or brown has been turned in as a potential brown recluse. There are hundreds of species of these spiders in California. They include ground spiders (Gnaphosidae), sac spiders (Cheiracanthium spp., Trachelas spp., and many of the liocranoid spiders), wolf spiders (Lycosidae), grass spiders (Agelenidae), orb weavers (Araneidae), and male crevice spiders (Filistatidae). More specifically, males of both the western black widow (Latrodectus hesperus) and the false black widow (Steatoda grossa) are frequently brought in for recluse verification. All of these brown spiders have eight eyes and can quickly be eliminated from consideration.


Eleven species of recluse spiders are native to the United States and a few non-natives have become established in circumscribed areas of the country. The brown recluse spider is the proper common name for only one species, Loxosceles reclusa. It is the most widespread of the North American recluse spiders and lives in the south central Midwest from Nebraska to Ohio and south through Texas to Georgia. Although the brown recluse does not live in California, we do have four species of native recluse spiders. The most common Californian recluse spider is the desert recluse, L. deserta. It is found mostly in the Sonoran and Mojave deserts, in the foothills of the lower San Joaquin Valley, and in adjacent areas of Mexico, all of which are sparsely populated by humans. In older literature, this spider was referred to as L. unicolor. There are additional species (L. russelli, L. palma, L. martha) but they are so uncommon that they are of scientific interest only.

In addition to these native species, a South American recluse spider, Loxosceles laeta (pronounced "LEE-ta"), has become established in portions of Los Angeles (Alhambra, Sierra Madre, Monterey Park). This spider, however, seems to be confined to a very limited area in Los Angeles County even though it has lived there for over 30 years. Also, occasional interceptions of the Mediterranean recluse, L. rufescens, are found in commercial goods shipped from out-of-state, but no populations of this spider have been found in California.

Life History Characteristics

Recluse spiders, as their name implies, are reclusive. These nocturnal spiders emerge from their retreats at night and actively hunt down prey or may wait for prey to land in the small area several inches from their retreat. Although they do not build webs to capture prey, they do use silk to build a retreat in which they hide during the day. As dawn approaches, they may seek shelter in dark places such as clothing or shoes. Also, mature males roam in search of females. It is these two behaviors that can bring them into contact with people.

In nature, recluses are found in cracks and crevices in and under rocks. Recluses have very much benefited from human-altered environments where they are readily found under trash cans, plywood, tarps, or rubber tires, in boxes, etc. They are synanthropic (found in association with humans) and therefore are considered a "house" spider. In fact, in South America the recluse species have common names that translate as "the spider behind the picture" or "the spider in the corner."

Recluse spiders are relatively long lived. Among the various species, they mature after about 1 year and average a 2- to 4-year life span with some living more than 7 years under laboratory conditions. They are also well known for surviving long periods (6-12 months) without food before perishing.

Abundance of Recluses

One consistent life history characteristic of recluse spiders is that in the right environment their populations are usually dense. Loxosceles reclusa is a common house spider in the midwestern United States. If you find recluses, you do not find one, you find many. Examples for the brown recluse include 9 under a piece of plywood in Oklahoma, 52 in an indoor laboratory, and 6 under a waterbed frame in Arkansas, 150 in a Kansas home, 40 collected in a Missouri barn in 1 hour, and 44 in sticky traps in a Tennessee home in 1 day.

Similarly, for the desert recluse in California, 12 of these spiders were collected under a doghouse in Yucca Valley and six were removed from a cottage bedroom in the Mojave Desert. In a study in Chile, 645 of 2189 homes that were searched contained the South American recluse spider, L. laeta. The five most infested homes averaged 163 spiders each and in none of these houses had spider bites been reported.

Unlike many other spiders that disperse by either migrating or being carried by air currents when small ("ballooning"), recluse spiders can only expand outside their native range as a result of human intervention. There are fewer than 10 documented cases of the spider being collected in California, spanning more than 4 decades, typically in facilities that receive goods from out of state. Searching the immediate area yielded no additional brown recluses and therefore they were considered to be individual stowaways. Undoubtedly, more brown recluses have been inadvertently brought into the state via commerce and the relocation of household belongings; however, amazingly few specimens have ever been collected. Never have any of these translocated spiders been able to establish a foothold and start a population in California. Considering that there are millions of brown recluses cohabiting with people in the southcentral Midwest and brown recluse bites are only an occasional occurrence there, California does not have anywhere near sufficient populations of these spiders to be responsible for the number of cases or illnesses that are attributed to them.


One reason for the great "awareness" of the recluse spiders throughout the United States is that necrotic wounds are misdiagnosed as "brown recluse bites." Although recluses can cause these wounds, the biological data involving the distribution of the spider indicate that most of these diagnoses are incorrect. A world-renowned toxicology physician who worked at University of Southern California Medical Center estimates that most spider bites in California referred to him were actually the work of other arthropods and that 60% of "brown recluse spider bite" diagnoses came from areas where no Loxosceles spiders were known to exist. Nationwide, some "brown recluse bites" were subsequently correctly diagnosed as Staphylococcus infection, Streptococcus ("flesh-eating bacteria") infection, Lyme disease, herpes simplex, diabetic ulcer, or bites from bedbugs, mites, ticks, small wasps, biting flies, or other spiders.

In addition, in one case where the offending spider was killed in the act of biting, a Californian doctor misidentified the spider as a brown recluse even though the spider had eight eyes, stripes on the cephalothorax, a patterned abdomen, and spines on the legs. In any event, 90% of all brown recluse bites in the Midwest heal without severe problems and millions of people have lived there for years without experiencing bites.


If you do not live in the shaded areas on the map, you do not need to be concerned with recluse spiders in California. If you do live within the range of these spiders, you still need to verify that you have recluses on your property before attempting control. Not all micro-habitats within the shaded areas will be suitable for recluse survival. For example, even though L. laeta occurs in densely populated sections of Los Angeles, this species is usually found in dark commercial and municipal storage basements.

This leaves the desert recluse as the only Californian recluse of concern and a minor one at that. After verifying that you do have desert recluses in your home or workplace, there are steps you can take to reduce encounters with them that are similar for reducing encounters with spiders in general. The most important thing you can do is remove and reduce trash and rubbish from your property, such as woodpiles, boxes, plywood, tires, and trash cans--especially if they are stored right next to the house. With attached garages, block off house access by sealing cracks around doors and access holes for electrical conduits or plumbing. In the bedroom, move the bed away from the wall and remove any skirts around the bed. This minimizes chances that a spider can crawl onto the bed. In the Midwest, some brown recluse bites occur when a sleeping person rolls over during the night, and the trapped spider bites in self defense. Do not leave clothes and shoes on the floor, or shake them if they are left out. Apparel and equipment that is only occasionally worn (gardening clothes and gloves, boots, baseball mitts, roller skates, etc.) should be stored in tightly closed plastic bags, especially if stored in the garage or other dark storage areas.

Typically, pesticide control of spiders is difficult unless you actually see the spider and are able to spray it. There are various insecticides available in retail outlets labeled for spider control. It is just as easy and much less toxic to crush the spider with a rolled up newspaper or your shoe. You can also remove a spider from your home by placing a jar over it and slipping a piece of paper under the jar that then seals off the opening of the jar when it is lifted up. If you plan to send the spider to an expert for identification, try to keep it in an undamaged condition because a crushed specimen may be difficult to identify.

Freakshow, (Bob)

Jeep stands for,
Just Empty Every Pocket