Ouch!  What was that?  I think I was just bit by a spider!!  I don’t like spiders, but some people do.  Do you like spiders?  If you are afraid of spiders you have something called arachnophobia.  (All links with an * refer to a dictionary).  That is the fear of arachnids*.  To find out what an arachnid is, click on the word in the underlined link.
    In this webquest, you will research information about spiders and complete activities to help you have an understanding of spiders and their relatives.

The Task
 

Resources

Classroom books:
Spiders
Creepy Crawlies
Wolfie
Anasai the Spider
Magic School Bus Spins a Web
Charlotte’s Web
The Big Bug Book
Amazing Spiders

Internet resources available with task
Other internet resources:
Spider Resources
Ask Jeeves
Hobo Spider

The Process
1.  Use groups of 2-3 students
2.  Research facts about spiders:
        Be able to identify the difference between a spider and an insect
        Write an informative paragraph about spiders
3.  Draw and label the parts of a spider
4.  Make a spider web
5.  Learn other interesting facts about spiders
    Be able to identify a statement as a fact or an opinion
6.  Write a narrative with you as the main character - a spider

Evaluation
 
 

Conclusion
You have learned many facts about spiders and other arthropods related to spiders.  Through this web quest, you have also learned how to stay on a topic (main idea), discover facts and opinions, follow directions for making projects, write creatively,

Here are some of the spiders I have found around my house and yard

Click on the thumbnail images to view more pictures and information about the spiders

Araneus diadematus Large European Garden Spiders who create large orb webs Callobius severus Large, interesting spiders who only live in the Pacific Northwest Cybaeus signifer Pimoa altioculata Tegeneria sp. Various Funnel Web spiders Pholcus phalangioides Daddy Long Legs Spiders Metellina sp. A small orb weaver, common around my house in late fall. Miscellaneous Spiders Here are some other spiders I haven’t idetified yet Grammastola rosea My first pet Tarantula, a Chilean Rose Hair Brachypelma albopilosa My other pet Tarantula, a Curly Haired tarantula.

Myths and a few fatal poisonings have made many people afraid of spiders. The only dangerous spiders in the northeast, however, are the very rare black widow and brown recluse spiders. These spiders are not native to the northeast, but may be occasionally transported here (the brown recluse is from the southwestern United States and the black widow is from the southern United States). Other spiders may be annoying due to their webs, but, unpopular as they are, most spiders are shy and harmless to humans. Most have fangs too small or weak to puncture human skin. They usually will not attempt to bite unless accidentally trapped or held. Spiders are beneficial, feeding on harmful insects (flies, crickets, etc.) and mites in and around the home, yard, garden and field

Description:

Spiders have eight legs (four pairs), and lack wings and antannae, but all vary in size, shape and color. They have two body regions: a cephalothorax (fused head with thorax) and an abdomen. Most spiders have eight eyes, some only six and several have fewer or none. All have a pair of jaw-like structures (chelicerae) which are hollow claw-like fangs through which venom can be ejected. The tip of the abdomen has silk-spinning glands. Young spiders (spiderlings) resemble adults except for their smaller size and coloration. Males are usually smaller than females.

All spiders produce venom that is poisonous to their normal prey of insects, mites and other small arthropods. Venom is injected through the fangs to immobilize the prey. Since spiders can only ingest liquids, digestive fluids are either injected or regurgitated into the prey.

Spiders produce silk, secreted as a liquid through the spinnerets, which hardens on contact with air. Different types and textures of silk may be used to construct snares or webs, egg sacs, draglines and ballooning threads. Some spiders use web snares to trap prey, and all species construct a silk sac to deposit eggs. Many spiders attach draglines of silk to the substrate at intervals wherever they go, appearing to have a silk thread to hang onto when knocked from their perch. Some spiderlings sail through the air (ballooning) on wind currents. Young spiders climb to a high point and release silk strands until the drag from the wind is sufficient to support their weight. They then release their hold and sail away, often for considerable distances. These ballooning threads (gossamer) can fill the air on clear days as spiderlings disperse to new areas.

Life Cycle:

Spiders lay eggs within a silken egg sac that is often ball-shaped and either hidden in the web or carried by the female. Spiders may produce several egg sacs, each containing several hundred eggs. One female may produce as many as 3,000 eggs in a series of several sacs over a period of time. Eggs may hatch a few weeks later (or the following spring). Spiders reach adulthood in one year. For a spider to grow, it must shed its skin (molt) usually four to twelve times before maturity. Most spiders live either one to two seasons. Spiders may overwinter as eggs, spiderlings in the egg sac, immature spiders living outside the egg sac or as adults.

Common Household Spiders:

Orb Weaver or Garden Spider (family Araneidae): These spiders all construct the characteristic circular, flat wheel-like web (orb web) in which flying insects are trapped. Some construct elaborate and beautiful, large webs in gardens and tall vegetation, especially obvious in the late summer and early autumn months. They have poor vision and locate the prey by feeling the vibration and tension of the threads in their web and then quickly, by turning the captive with their legs, use silk to wrap the victim. The prey is bitten before being carried to the center of the web or to a corner where it is eaten. Anything inedible is cut out of the web and dropped to the ground. In the fall, female orb-weavers die soon after producing egg sacs containing several hundred eggs. Eggs may hatch soon after or not until the following spring. Many adult spiders are large, some with oddly shaped abdomens (pointed spurs, conical tubercles, etc., in various colors of black, yellow, orange, red, white, brown, green, etc.).

One common garden spider, known as the black and yellow garden spider, has silver hairs on the back of its forward body section and a large abdomen marked in black and bright yellow (or orange). The common garden spider is approximately 25 mm (1 inch) long and hangs head down in the center of the web. It is often found in brambles, bushes and tall grasses in open, sunny places near human habitations where flying insects blunder into the trap. Egg sacs are spherical and narrowed at one end and covered with a tough brown, paper-like silk. These spiders are not considered dangerous, despite their formidable appearance, but they can bite if handled or molested.

Wolf Spiders (family Lycosidae): Female wolf spiders are large, hairy, running spiders, often confused with tarantulas. They may be brown, black, gray, white, yellow, orange or green. Many have a stripe or pattern the length of the first, and sometimes the second, body segment. They are nocturnal and usually occur outdoors but may wander indoors, especially into cellars and basements in late summer and fall when cooler temperatures prevail. These hunting spiders, which do not construct webs, carry the large, globular egg sac attached to spinnerets under the abdomen. Upon hatching, the spiderlings climb onto their mother’s back and ride there for several days before dispersing. They do not establish themselves indoors and are not aggressive, but may bite if handled or molested.

Jumping Spiders (family Salticidae): These common spiders are no more than 12 mm (1/2 inch) long, and are striking in appearance, with bright colors often heightened by iridescent scales. They are hairy and short-legged and can jump several times their own length. Some are black with spots of orange or red on the top surface of the abdomen; others are brownish-gray and yellow with whitish markings. Their movements are quick (irregular gait) with short, sudden jumps. Jumping spiders are active during the day and like sunshine, normally living outdoors, but are sometimes found indoors on walls, windows, screens, doors, etc. They are sometimes carried indoors on firewood. They depend on their vision (keenest of all spiders) and leaping ability to catch prey, especially flies. After mating, the female constructs a silk cocoon for her eggs and guards it. Some can bite humans if handled.

House or Cobweb Spider (family Therididae): The female house spider is larger than the male, about 10 mm (1/3 inch) long, gray to brown with a rounded, globular abdomen mottled with several dark stripes on the upper side. House spiders spin their webs in dark corners of moist rooms and outdoors. They hang upside down in the center of an irregular cobweb. Sticky threads on the outside of the web entangle many insects, especially flies, which are bitten and sucked dry. Females are fertilized several times during a lifetime and lay up to nine egg sacs, each containing 200 or more eggs. Young hatch in about eight days, staying within the sac until after the first molt. Spiderlings take several months to mature.

Cellar Spiders (family Pholcidae): Cellar spiders have bodies which are about 2-6 mm (1/16-1/4 inch) in length and long, slender legs. Although similar in appearance to daddy-long-legs, cellar spiders have rounded or elongate bodies which are light-colored, gray or brown. Common in barns, cellars and damp warehouses, they hang upside-down under sheetlike or irregular webs.

Poisonous Spiders:

Brown Recluse Spider (Loxosceles reclusa): Brown recluse spiders belong to a group of spiders commonly known as violin spiders or fiddlebacks, because of a characteristic fiddle-shaped pattern on their head region. The brown recluse is golden brown with a dark brown or black "fiddle," which is often shiny. They range from 5-15 mm (1/4 to 3/4 inch) long. Brown recluse spiders are found primarily in the South and Midwest. They are rarely, if ever, found in Rhode Island. Brown recluse spiders live in basements and garages of houses, often hiding behind boards and boxes. Bites sometimes occur when the spiders hide in towels or clothing. They are seldom aggressive and bite only when threatened or injured.

Adult brown recluse spider. Photo from the University of Kentucky Cooperative Extension Service.

The severity of the bite of the brown recluse may vary from no symptoms at all to a reaction that is very severe. Often there is a systemic reaction within 24-36 hours of the bite characterized by restlessness, fever, chills, nausea, weakness and joint pain. There is often tissue death at the site of the bite. In some severe cases, a wound may develop that lasts several months. In all cases, a physician should be notified. If at all possible, kill and take the spider to the physician for positive identification. It is important to note that many wolf spiders are similar in appearance to the brown recluse, but the wolf spider is hairy, larger and more robust than the brown recluse.

Black Widow Spider (Latrodectus mactans): Like the brown recluse, black widow spiders are not generally found in Rhode Island, except when brought here by travelers. The female is usually black with a red spot or hourglass-shaped mark on its round abdomen. The male usually has light streaks on its abdomen. The spider is about 38 mm (1 1/2 inches) in diameter, including legs. In infested areas, black widow spiders are common around wood piles, and are frequently encountered when homeowners carry firewood into the house. They are found under eaves, in boxes, outdoor toilets, meter boxes and other undisturbed places. The female black widow occasionally eats the male after mating (hence the name). She hangs belly-upward and rarely leaves the web. The black widow is not aggressive, but it will bite instinctively when touched or pressed. Be very careful when working around areas where black widow spiders may be established. Wear gloves and pay attention to where you are working. Black widow bites are sharp and painful, and the victim should seek medical attention immediately.

Adult black widow spider. Photo by Ronald F. Billings, Texas Forest Service.

Control:

Sanitation is critical in successful spider control. Indoors, the spiders, webs and egg sacs can be collected and destroyed with a strong suction vacuum cleaner. Move and dust often behind and under furniture, stored materials, wall hangings and corners of ceilings. Eliminate other household pests (prey) such as flies, ants and pantry pests, which attract spiders. Be sure to control excess moisture and humidity, keeping basements, crawl spaces, porches, etc., as dry as possible. Outdoors, clean up woodpiles, trash, rocks, compost piles, old boards and other debris around the house foundation where spiders often live. Be sure to seal or caulk cracks and crevices around windows and doors and install tight-fitting screens as needed where spiders can enter the house. Use a hose with high-pressure water on the outside of the house to knock down and destroy webs, egg sacs and spiders. Use yellow or sodium vapor light bulbs at outside entrances to reduce night-flying insects (prey) which attract spiders.

We generally do not recommend insecticides for spider control, but when necessary, spiders can be killed with aerosol cans of either flying insect killer or residual sprays such as crack and crevice sprays.

1. Any of numerous arachnids of the order Araneae, having a body divided into a cephalothorax bearing eight legs, two poison fangs, and two feelers and an unsegmented abdomen bearing several spinnerets that produce the silk used to make nests, cocoons, or webs for trapping insects.
2. One that resembles a spider, as in appearance, character, or movement.
3. New England, Upper Northern, & South Atlantic U.S. See frying pan. See Regional Note at frying pan.
4. A trivet.

[Middle English spither, from Old English spīthra.]

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Wikipedia: spider

Spider
Orb weaver spider (family: Araneidae)
Scientific classification
Kingdom: Animalia Phylum: Arthropoda Class: Arachnida Order: Araneae Clerck, 1757
Diversity
111 families, 40,000 species
Suborders
Mesothelae Mygalomorphae Araneomorphae See table of families

Spiders are predatory invertebrate animals that have two body segments, eight legs, no chewing mouth parts and no wings. They are classified in the order Araneae, one of several orders within the larger class of arachnids, a group which also contains scorpions, whip scorpions, mites, ticks, and opiliones (harvestmen). The study of spiders is known as arachnology.

All spiders produce silk, a thin, strong protein strand extruded by the spider from spinnerets most commonly found on the end of the abdomen. Many species use it to trap insects in webs, although there are also many species that hunt freely. Silk can be used to aid in climbing, form smooth walls for burrows, build egg sacs, wrap prey, and temporarily hold sperm, among other applications.

All spiders except those in the families Uloboridae and Holarchaeidae, and in the suborder Mesothelae (together about 350 species) can inject venom to protect themselves or to kill and liquefy prey. Only about 200 species, however, have bites that can pose health problems to humans.^[1] Many larger species’ bites may be quite painful, but will not produce lasting health concerns.

Spiders are found all over the world, from the tropics to the Arctic, living underwater in silken domes they supply with air, and on the tops of mountains. In 1973 Skylab 3 took two spiders into space to test their web-spinning capability in free-fall.

Morphology

Spider anatomy:
(1) four pairs of legs
(2) cephalothorax
(3) opisthosoma

Spiders, unlike insects, have only two body segments (tagmata) instead of three: a fused head and thorax (called a cephalothorax or prosoma) and an abdomen (called the opisthosoma). The exception to this rule are the assassin spiders, whose cephalothorax seems to be almost divided into two independent units. Except for a few species of very primitive spiders (family Liphistiidae), the abdomen is not externally segmented. The abdomen and cephalothorax are connected with a thin waist called the pedicle or the pregenital somite, a trait that allows the spider to move the abdomen in all directions. This waist is actually the last segment (somite) of the cephalothorax and is lost in most other members of the Arachnida (in scorpions it is only detectable in the embryos).

Cephalothorax

All spiders have eight legs, although a few ant-mimicking species use their front legs to imitate antennae, which spiders lack. Their eyes are single lenses rather than compound eyes, ranging from simple light/dark-receptors to eyes rivaling those of a pigeon (some jumping spiders).

They have pedipalps (or just palps), at the base of which are coxae or maxillae next to their mouth that aid in ingesting food; the ends of the palp are modified in adult males into elaborate and often species-specific structures used for mating. Since they don’t have any antennae, they use specialised and sensitive hairs on their legs to pick up scent, sounds, vibrations and air currents.

Spiders lack the ability to chew their food. Instead, like other arachnids, they have a tiny proboscis which they use to suck up the liquid parts of their prey. However, they are able to eat their own silk.

Sense organs

Multiple eyes of the jumping spider Platycryptus undatus

Spiders usually have eight eyes in various arrangements, a fact which is used to aid in taxonomically classifying different species. Most species of the Haplogynae have six eyes, although some have eight (Plectreuridae), four (eg., Tetrablemma) or even two (most Caponiidae) eyes. Sometimes one pair of eyes is better developed than the rest, or even, in some cave species, there are no eyes at all. Several families of hunting spiders, such as jumping spiders and wolf spiders, have fair to excellent vision. The main pair of eyes in jumping spiders even see in color.

Net-casting spiders have enormous, compound lenses that give a wide field of view and gather available light very efficiently.

However, most spiders that lurk on flowers, webs, and other fixed locations waiting for prey tend to have very poor eyesight; instead they possess an extreme sensitivity to vibrations, which aids in prey capture. Vibration sensitive spiders can sense vibrations from such various mediums as the water surface, the soil or their silk threads. Also changes in the air pressure can be detected in the search for prey.

Respiration and circulation

Rear side of a spider

Spiders have an open circulatory system; i.e., they do not have true blood, or veins to convey it. Rather, their bodies are filled with haemolymph, which is pumped through arteries by a heart into spaces called sinuses surrounding their internal organs.

Spiders have developed several different respiratory anatomies, based either on book lungs, a tracheal system, or both. Mygalomorph and Mesothelae spiders have two pairs of book lungs filled with haemolymph, where openings on the ventral surface of the abdomen allow air to enter and diffuse oxygen. This is also the case for some basal araneomorph spiders like the family Hypochilidae, but the remaining members of this group have just the anterior pair of book lungs intact while the posterior pair of breathing organs are partly or fully modified into tracheae, through which oxygen is diffused into the haemolymph or directly to the tissue and organs. This system has most likely evolved in small ancestors to help resist desiccation. The trachea were originally connected to the surroundings through a pair of spiracles, but in the majority of spiders this pair of spiracles has fused into a single one in the middle, and migrated posterior close to the spinnerets.

Among smaller araneomorph spiders we can find species who have evolved also the anterior pair of book lungs into trachea, or the remaining book lungs are simply reduced or missing, and in a very few the book lungs have developed deep channels, apparently signs of evolution into tracheae. Some very small spiders in moist and sheltered habitats have no breathing organs at all, and instead breathe directly through their body surface. In the tracheal system, oxygen interchange is much more efficient, enabling cursorial hunting (hunting involving extended pursuit) and other advanced characteristics as having a smaller heart and the ability to live in drier habitats.

Digestion

A spider in the process of wrapping a bluebottle caught in its web

Digestion is carried out internally and externally. Spiders that do not have powerful chelicerae, secrete digestive fluids into their prey from a series of ducts perforating their chelicerae. These digestive fluids dissolve the prey’s internal tissues. Then the spider feeds by sucking the partially digested fluids out. Other spiders with more powerfully built chelicerae masticate the entire body of their prey and leave behind only a relatively small residue of indigestible materials. Spiders consume only liquid foods. Many spiders will store prey temporarily. Web weaving spiders that have made a shroud of silk to quiet their envenomed prey’s death struggles will generally leave them in these shrouds and then consume them at their leisure.

Spiders are capable of digesting their own silk, so some spiders may eat their used webs. When a spider drops down on a single strand of silk and then returns, it will generally rapidly consume the strand of silk on its way back up.^{[citation needed]}

Spinnerets

The abdomen has no appendages except from one to four (usually three) modified pairs of movable telescoping organs called spinnerets, which produce silk. The suborder Mesothelae is unique in having only two types of silk glands - thought to be the ancestral condition. All other spiders have the spinnerets further towards the posterior end of the body where they form a small cluster, and the anterior central spinnerets on the tenth segment are lost or reduced (suborder Mygalomorphae), or modified into a specialised and flattened plate called the cribellum (parts of suborder Araneomorphae), which produces a thread made up of hundreds to thousands of very fine dry silk fibers resulting in a woolly structure that traps prey. The cribellate spiders were the first spiders to build specialized prey catching webs. Later some groups evolved (called ecribellate) that use silk threads dotted with sticky droplets to capture prey ranging from small arthropods to sometimes even small bats and birds.

Size

Spiders occur in a large range of sizes. Charles Churchill discovered a spider 600 millimeters in diameter. The smallest, dwarf spiders of the subfamily Erigoninae, are less than 1 mm (about .05 inches) in body length. The largest and heaviest spiders occur among tarantulas, which can have body lengths up to 90 mm (about 3.5 inches) and leg spans up to 250 mm (about 10 inches).^[2]

Coloration

Only three classes of pigment (ommochromes, bilins and guanine) have been identified in spiders, although other pigments have been detected but not yet characterized. Melanins, carotenoids and pterins, very common in other animals, are apparently absent. In some species the exocuticle of the legs and prosoma is modified by a tanning process, resulting in brown coloration.^[3]

Bilins are found for example in Micrommata virescens, resulting in its green color. Guanine is responsible for the white markings of the European garden spider Araneus diadematus. It is in many species accumulated in specialized cells called guanocytes. In genera such as Tetragnatha, Leucauge, Argyrodes or Theridiosoma, guanine creates their silvery appearance. While guanine is originally an end-product of protein metabolism, its excretion can be blocked in spiders, leading to an increase in its storage.^[3]

Structural colors occur in some species, which are the result of the diffraction, scattering or interference of light, for example by modified setae or scales. The white prosoma of Argiope results from hairs reflecting the light, Lycosa and Josa both have areas of modified cuticle that act as light reflectors.^[3]

Golden orb weavers in Parque Nacional Corcovado, a female in the foreground and a male behind her

Pisaura mirabilis guarding her egg sac

Spider showing its epigyne

Bird dropping spider with its unusual egg sacs

Spiderlings on a web

The exuvia of a spider after moulting

Life cycle

The spider life cycle progresses through three stages: the embryonic, the larval, and the nympho-imaginal.

The time between when an egg is fertilized and when the spider begins to take the shape of an adult spider is referred to as the embryonic stage. As the spider enters the larval stage, it begins to look more and more like a full grown spider. It enters the larval stage as a prelarva and, through subsequent moults, reaches its larval form, a spider-shaped animal feeding off its yolk supply. After a few more moults (also called instars) body structures become differentiated. Soon, all organ systems are complete and the animal begins to hunt on its own; it has reached the nympho-imaginal stage.^[4]

This stage is differentiated into two sub-stages: the nymph, or juvenile stage and the imago, or adult stage. A spider does not become sexually mature until it makes the transition from nymph to imago.^[4] Once a spider has reached the imago stage, it will remain there until its death. After sexual maturity is reached, the general rule is that they stop moulting,^{[citation needed]} but the females of some non-araneomorph species will continue to moult the rest of their lives.

Lifespan

Many spiders may only live for about a year, but a number will live two years or more, overwintering in sheltered areas. The annual influx of ‘outdoor’ spiders into houses in the fall is due to this search for a warm place to spend the winter. It is common for female tarantulas to live up to twenty years.

Reproduction

Spiders reproduce by means of eggs, which are packed into silk bundles called egg sacs. Spiders often use elaborate mating rituals (especially the visually advanced jumping spiders) to allow conspecifics to identify each other and to allow the male to approach and inseminate the female without triggering a predatory response. If the approach signals are exchanged correctly, the male spider must (in most cases) make a timely departure after mating to escape before the female’s normal predatory instincts return.

Sperm transmission from male to female occurs indirectly. When a male is ready to mate, he spins a web pad upon which he discharges his seminal fluid. He then dips his pedipalps (also known as palpi), the small, leg-like appendages on the front of his cephalothorax, into the seminal fluid, picking it up by capillary attraction. Mature male spiders have swollen bulbs on the end of their palps for this purpose, and this is a useful way to identify the sex of a spider in the field. With his palps thus charged he goes off in search of a female. Copulation occurs when the male inserts one or both palps into the female’s genital opening, known as the epigyne. He transfers his seminal fluid into the female by expanding the sinuses in his palp. Once the sperm is inside her, she stores it in a chamber and only uses it during the egg-laying process, when the eggs comes into contact with the male sperm for the first time and are fertilized; this may be why the vivipary has never evolved in spiders.^{[citation needed]}

Very unusual behaviour is seen in spiders of the genus Tidarren: the male amputates one of his palps before maturation and enters his adult life with one palp only. The palpi constitute 20% of the body mass of males of this species, and since this weight greatly impedes its movement, by detaching one of the two he gains increased mobility. In the Yemeni species Tidarren argo, the remaining palp is then torn off by the female. The separated palp remains attached to the female’s epigynum for about four hours and apparently continues to function independently. In the meantime the female feeds on the palpless male.^[5]

Sacrificial males

Main article: Spider cannibalism

It is a common belief that male spiders, which usually are significantly smaller than the females, are likely to be killed after or during mating, or sometimes even before mating can occur.

Even in some species of black widow, which are named exactly for this belief, the male may live in the female’s web for some time without being harmed. However, the male of the closely related Australian redback spider is killed ritually by the females after it inserts its second palpus in the female genital opening; in over 60% of cases the female then eats the male.^[6] Males that ’sacrifice’ themselves gain the benefit of increasing their paternity relative to males who do not get cannibalized, by feeding the egg-laying female.

In many other species, males are sometimes killed by females. In at least some of these cases it’s likely that the males are simply mistaken as prey. The risk of this happening is greater if the female is hungry. To counter this, some male spiders offer a "bribe" to the female, in form of a fly or other prey, prior to the mating.

Ecology

Spiders have a great range of variation and lifestyle, although all are predatory.

While spiders are generalist predators, in actuality their different methods of prey capture often determine the type of prey taken. Thus web-building spiders rarely capture caterpillars, and crab spiders that ambush prey in flowers capture more bees, butterflies and some flies than other insects. Groups of families that tend to take certain types of prey because of their prey capture methods are often called guilds. A few spiders are more specialized in their prey capture. Dysdera captures and eats sowbugs, pillbugs and beetles, while pirate spiders eat only other spiders. Bolas spiders in the family Araneidae use sex pheromone analogs to capture only the males of certain moth species. Despite their generally broad prey ranges, spiders are one of the most important links in the regulation of the populations of insects.

Behavior

Spiders show a wide variety of behavior, from the ballet-like mating dances of certain jumping spiders to the seeming athletics of bolas spiders snatching their prey. Most diversity comes with the mode of predation, for example whether the spider waits for it in its orb web, or hunts it down.

Predatory techniques

Main article: Spider diversity

A spider hiding in its leaf (located at the center of its web)

Although spider predatory technique is diverse, as soon as a spider makes contact with its prey, it will usually bite it.

Spiders bite their prey, and occasionally animals that cause them pain or threaten them, for two reasons: First, they inflict mechanical damage, which, in the case of a spider that is as large as or larger than its prey, can be severe. Second, they can inject venom via their hollow fangs. Many genera, such as the widow spiders, inject neurotoxins that can spread through the prey’s entire body and interfere with vital body functions. Other genera inject venom that produces tissue damage at the bite location. In the larger victims that do not die from these attacks, painful lesions over a wide area can remain for an extended time. The spitting spiders have modified their poison glands to produce a mixture of venom and sticky substance that works as glue and immobilises the prey.

Although there are no herbivore spiders, some species in the families Anyphaenidae, Corinnidae, Clubionidae, Thomisidae and Salticidae feed on plant nectar.^[7] Several spider species are also known to feed on bananas, marmalade, milk, egg yolk and sausages in captivity.^[7]

Spider webs

Main article: Spider web

Having completed its web, a spider in the forests of Malaysia awaits its prey. Appears to be some species of Nephila.

A golden silk orb-weaver (Nephila clavipes?), member of the family Nephilidae.

Some spiders spin funnel-shaped webs, others make sheet webs, spiders like the black widow make tangled, maze-like, webs, and still others make the spiral "orb" webs that are most commonly associated with spiders. These webs may be made with sticky capture silk, or with "fluffy" capture silk, depending on the type of spider. Webs may be in a vertical plane (most orb webs), a horizontal plane (sheet webs), or at any angle in between. Most commonly found in the sheet-web spider families, some webs will have loose, irregular tangles of silk above them. These tangled obstacle courses serve to disorient and knock down flying insects, making them more vulnerable to being trapped on the web below. They may also help to protect the spider from aerial predators such as birds and wasps.

The spider, after spinning its web, will then wait on, or near, the web for a prey animal to become trapped. The spider can sense the impact and struggle of a prey animal by vibrations transmitted along the web lines.

Other species of spiders do not use webs for capturing prey directly, instead pouncing from concealment (e.g. trapdoor spiders) or running them down in open chase (e.g. wolf spiders). The net-casting spider balances the two methods of running and web-spinning in its feeding habits. This spider weaves a small net which it attaches to its front legs. It then lurks in wait for potential prey and, when such prey arrives, lunges forward to wrap its victim in the net, bite and paralyze it. Hence, this spider expends less energy catching prey than a primitive hunter such as the Wolf spider. It also avoids the energy cost of weaving a large orb-web. The diving bell spider does not use its web directly in prey capture, but has modified it into an underwater diving bell. Even species whose ancestors were building spiral orb webs have given rise to spiders who no longer make webs, for instance some Hawaiian spiny-legged spiders (genus Tetragnatha, family Tetragnathidae) have abandoned web construction entirely.

Some spiders manage to use the ’signaling snare’ technique of a web without spinning a web at all. Several types of water-dwelling spiders will rest their feet on the water’s surface in much the same manner as an orb-web user. When an insect falls onto the water and is ensnared by surface tension, the spider can detect the vibrations and run out to capture the prey.

Hunting spiders

An ant-mimicking jumping spider

Wolf spider, an active hunter

Many spiders do not build webs for catching prey. Some examples include:

• Brazilian wandering spider
• Brown recluse spider
• Huntsman spiders
• Jumping spiders
• Lynx spiders
• Nursery web spiders
• Spitting spiders
• Tarantulas
• Wolf spiders (Lycosidae)
• Yellow sac spider
• Assassin spider

Ambush predators

Some actively lure prey (the Bolas spiders) and may capture them with a sticky ball of silk on a line; others (like the crab spiders, trapdoor spiders, or the six-eyed sand spider) wait in a high-traffic area and directly attack their prey from ambush.

Defense

All spiders will attempt to protect themselves by biting, especially if they are unable to flee. Some tarantulas have a second kind of defense, a patch of urticating hairs, or urticating setae, on their abdomens, which is generally absent on modern spiders and Mesothelae. These ultra-fine hairs causes irritation and sometimes even allergic reactions in the attacker. Certain other species have specialized defense tactics. For example, the golden wheeling spider (Carparachne aureoflava) of the desert of Namibia escapes tarantula hawks (a species of wasp that lays its eggs in a paralyzed spider so the larvae have enough food when they hatch) by flipping onto its side and cartwheeling away.

Social spiders

A few species of spiders that build webs live together in large colonies and show social behavior, albeit not as well evolved as in social insects. The most social species is probably Anelosimus eximius, which can form colonies of up to fifty thousand individuals.

Web types

Tangleweb spiders

Members of this group (family Theridiidae) are characterized by irregular, messy-looking, tangled, three-dimensional (non-sticky) webs, generally low and anchored to the ground or floor and wall. They are commonly found in or near buildings; some build webs in bushes. The spider generally hangs in the center of its web, upside-down. Prey is generally ground-dwelling insects such as ants or crickets, in addition to small flying insects. These include the infamous black widows, the minute happyface spider, and thousands of other species.

Orb web spiders

Nephila clavata, a golden orb weaver

Spiders in several families (eg., Araneidae, Tetragnathidae, Nephilidae) spin the familiar spiral snare that most people think of as the typical spider web. On average, an orb-weaving spider takes 30 minutes to an hour to weave a web. They range in size from quite large (6+ cm) to very small (<1 cm), but all are quite harmless to humans, beyond the shock entailed from walking into a face-height web and having a large spider dangling from your nose. Many of the daytime hunters have a ‘ferocious’ appearance, with spines or large ‘fangs’, but they are almost invariably inoffensive, preferring to drop on a dragline to the ground when disturbed, rather than bite, which can nevertheless be quite painful.

Other forms of webs

Many other groups spin webs in a variety of structural styles.

Some (the Linyphiidae) make various forms of bowl- or dome-shaped webs with or without a flat sheet or a tangled web above or below. Some make a flat platform extending from a funnel-shaped retreat, with generally a tangle of silk above the web. The common northern hemisphere ‘funnel-web’, ‘house’ or ‘grass’ spiders are only superficially similar to the notorious Sydney funnel-web spider, and are generally considered to be quite harmless. Some of the more primitive group Atypidae may make tubular webs up the base of trees, from inside which they bite insects that land on the webbing. These spiders look quite ferocious, but are not generally considered to be particularly dangerous to humans.

Evolution

Main article: Spider evolution

A spider in Baltic amber

Trigonotarbids, spider-like arachnids, were among the oldest known land arthropods. Like spiders, they were terrestrial, respired through book lungs, and walked on eight legs with two additional legs adapted to use around their mouth. However, they were not true spiders, not even ancestral to them, but represented independent offshoots of the Arachnida.

True spiders (thin-waisted arachnids) evolved about 400 million years ago, and were among the first species to live on land. They are distinguished by abdominal segmentation and silk producing spinnerets. The Pedipalpi (including whip scorpions) are believed to constitute the sister group to the Araneae.^[8]

Most of the early segmented fossil spiders belonged to the Mesothelae, a group of primitive spiders with the spinnerets placed underneath the middle of the abdomen, rather than at the end as in modern spiders (Opisthothelae). They were probably ground dwelling predators of other primitive arthropods. Silk may have been used simply as a protective covering for the eggs, a lining for a retreat hole, and later perhaps for simple ground sheet web and trapdoor construction.

As plant and insect life diversified so also did the spider’s use of silk. Spiders with spinnerets at the end of the abdomen (Mygalomorphae and Araneomorphae) appeared more than 250 million years ago, presumably promoting the development of more elaborate sheet and maze webs for prey capture both on ground and foliage, as well as the development of the safety dragline.

By the Jurassic, the sophisticated aerial webs of the orb weaving spiders had already developed to take advantage of the rapidly diversifying groups of insects. A spider web preserved in amber, thought to be 110 million years old, shows evidence of a perfect orb web.^{[citation needed]} It is believed that adhesive capture threads, as opposed to cribellate threads, evolved about 135 million years ago.^[9]

The ability to weave orb webs is thought to have been "lost", and sometimes even re-evolved or evolved separately, in different breeds of spiders since its first appearance.

Taxonomy

Main article: Spider taxonomy

Araneae    Mesothelae    Opisthothelae        Mygalomorphae Araneomorphae

Almost 40,000 species of spiders (order Araneae) have been identified and are currently grouped into 111 families by arachnologists, but because of difficulties in collecting these often very minute and evasive animals, and because of many specimens stored in collections waiting to be described and classified, it is believed that up to 200,000 species may exist.

The order is composed of three suborders. In the non-venomous primitive Mesothelae, body segmentation is clearly visible, demonstrating the link of spiders with their segmented arthropod ancestors.

The two other suborders, the Mygalomorphae (trapdoor spiders, funnel-web spiders, tarantulas) and the Araneomorphae ("modern" spiders), are sometimes grouped together as Opisthothelae. The latter account for about 94% of all spider species.

Mesothelae

Liphistius sp.

Main article: Mesothelae

The Mesothelae include the only recent family Liphistiidae. Two more families (Arthrolycosidae and Arthromygalidae) are recognized from fossil evidence only.

The Liphistiidae are burrowing spiders only found in Southeast Asia, China, and Japan with about 90 species in 5 genera. Spiders of this remnant suborder are very rare, and are among the most "primitive" types of spiders in existence.

Recent Mesothelae are characterized by the narrow sternum on the ventral side of the prosoma. Several plesiomorphic characters may be useful in recognizing these spiders: there are tergite plates on the dorsal side and the almost-median position of the spinnerets on the ventral side of the opisthosoma.

Mygalomorphae

The tarantula Brachypelma smithi

Main article: Mygalomorphae

The Mygalomorphae are also called the Orthognatha, referring to the orientation of the fangs which point straight down and do not cross each other (cf Araneomorphae). This suborder includes the heavy bodied, stout legged spiders popularly known as tarantulas as well as the dangerous Australasian funnel-web spiders. They have ample poison glands that lie entirely within their chelicerae. Their chelicerae and fangs are large and powerful. Occasionally members of this suborder will even kill small fish, small mammals, etc. Most members of this suborder occur in the tropics and subtropics, but their range can extend farther toward the poles, e.g. into the southern and western regions of the United States and Canada, the northern parts of Europe and south into Argentina and Chile.

Araneomorphae

Araneus diadematus

Main article: Araneomorphae

The Araneomorphae, (previously called the Labidognatha), are often known as the modern spiders.

They are distinguished by having chelicerae that point diagonally forward and cross in a pinching action, in contrast to the Mygalomorphae (tarantulas and their close kin), where they point straight down. Most of the spiders that people encounter in daily life belong to this suborder, which makes up 94% of all spider species.

There are approximately 95 families in this suborder, ranging from the minute Patu digua (0.37 mm) to the big and flashy Argiope, from the common orb-weaver spiders to the abstruse assassin spiders, from the reclusive tree trapdoor spiders to the inquisitive jumping spiders.

Creatures often mistaken for spiders

In addition to the true spiders, there are several arachnids commonly mistaken for spiders, but which are not true spiders.

• Camel spider, a species of solifugid (also commonly called sun-spiders or wind-scorpions), are the source of many urban legends. Although they have no venom the camel spider has been known to attack humans, focusing on exposed skin, and with fangs capable of tearing human flesh.
• The daddy long-legs or harvestman is a member of the order Opiliones. These round-bodied arachnids have only two eyes and their heads are fused to their bodies. However, the name "daddy long-legs" is sometimes used to refer to cellar spiders, which have a similar leg shape; these are true spiders. Both are also often said to produce a deadly venom. While the harvestmen do not produce venom at all, the cellar spider’s venom is completely harmless to humans.

Spiders and people

Spider bites

Mouse Spider, Missulena bradleyi

Main article: Spider bite

Most spiders are unlikely to bite humans because they do not identify humans as prey. Spiders, even small ones, may however bite humans when pinched. For instance, a common jumping spider (Family: Salticidae), around ⅜ inch (1 cm) long, when pinched between the folds of a human’s palm may inflict a bite that is about as painful as a bee sting.

Spiders in the world which have been linked to fatalities in humans, or have been shown to have potentially fatal bites by toxicology studies of their venom, include:

• The Brazilian wandering spider
• The Australasian funnel-web spider
• The widow spiders, including the Australian redback spider
• The six-eyed sand spider, and possibly other spiders of genus Sicarius
• The recluse spiders

Spiders which likely are not deadly to humans, but which are nonetheless medically significant include:

• The hobo spider (this is doubtful, however)
• The yellow sac spider
• Certain species of tarantulas
• The false black widows

Spiders which can inflict painful bites (often similar to a bee sting), but whose bites generally do not cause any systemic or long-lasting effects, include:

• The huntsman spider
• The redback jumping spider (not to be confused with the very dangerous redback spider, the latter being one of the widow spiders).

None of these spiders will intentionally "come after you," but they should be removed from one’s house to avoid accidental injury. Many authorities warn against spraying poisons indiscriminately to kill all spiders, because doing so may actually remove one of the biological controls against incursions of the more dangerous species by ridding them of their competition.

If dangerous spiders are present in your area, be mindful when moving cardboard boxes and other such objects that may have become the shelter of a venomous spider. There is no need to be fearful; just do not grab a spider.

Spiders as food

Spiders, especially larger sorts, are eaten routinely or as a delicacy in various parts of the world, including Cambodia, Thailand, the Solomon Islands, and parts of South America.

Arachnophobia

Spinyback orbweaver

Moche Ceramic Depicting Spider. 300 A.D.

Main article: Arachnophobia

Arachnophobia is a specific phobia, an abnormal fear of spiders. It is among the most common of phobias. The reactions of arachnophobics often seem irrational to others (and sometimes to the sufferers themselves). People with arachnophobia tend to feel uneasy in any area they believe could harbor spiders or that has visible signs of their presence, such as webs. If they see a spider they may not enter the general vicinity until they overcome the panic attack that is often associated with their phobia. They may feel humiliated if such episodes happen in the presence of peers or family members. The fear of spiders can be treated by any of general techniques suggested for specific phobias.

Arachnophobia is also the title of a 1990 film, as well as a spin-off video game, in which (fictitious) deadly spiders overrun a small California town.

Spiders in symbolism and culture

Main article: Cultural depictions of spiders

There are many references to the spider in popular culture, folklore and symbolism. The spider symbolizes patience for its hunting with web traps, and mischief and malice for its poison and the slow death this causes. It symbolizes possessiveness and storage for its spinning of its prey into a ball and taking it to its burrow (for burrowing species).

Though not all spiders spin gossamer webs, spiders have been attributed by numerous cultures with the origination of basket-weaving, knotwork, weaving, spinning and net making. Spiders are pervasive throughout folklore and mythology. Spinning and binding is evident in the etymologies of the terms religion, yoga, tantra and wyrd.

The Moche people of ancient Peru worshipped nature.^[10] They placed emphasis on animals and often depicted spiders in their art. ^[11]

See also

• Spider diversity
• Identifying spiders
• Spider webs in space
• Endangered spiders

Footnotes

1. ^ Diaz, James H. (2004). The global epidemiology, syndromic classification, management, and prevention of spider bites. American Journal of Tropical Medicine and Hygiene 71 (2): 239-250.
2. ^ Spiders and their Kin, Herbert W. Levi and Lorna R. Levi, Golden Press, p. 20 and p. 44
3. ^ ^{a b c} Oxford, G.S. & Gillespie, R.G. (1998). Evolution and Ecology of Spider Coloration. Annual Review of Entomology 43:619-643. doi:10.1146/annurev.ento.43.1.619
4. ^ ^{a b} Foelix, Rainer F (1996). Biology of Spiders, 2nd edition.
5. ^ Knoflach, B. & van Harten, A. (2001). Tidarren argo sp. nov. (Araneae: Theridiidae) and its exceptional copulatory behaviour: emasculation, male palpal organ as a mating plug and sexual cannibalism. Journal of Zoology 254: 449–459. doi:10.1017/S0952836901000954.
6. ^ Andrade, Maydianne C.B. (2003). Risky mate search and male self-sacrifice in redback spiders. Behavioral Ecology 14: 531–538.
7. ^ ^{a b} Jackson, R.R. et al. (2001). Jumping spiders (Araneae: Salticidae) that feed on nectar (PDF). J. Zool. Lond. 255: 25-29.
8. ^ Coddington, J.A. & Levi, H.W. (1991). Systematics and Evolution of Spiders (Araneae). Annu. Rev. Ecol. Syst. 22: 565-592.
9. ^ Opell, B. D. (1997). The material cost and stickiness of capture threads and the evolution of orb-weaving spiders. Biological Journal of the Linnean Society 62:443-458.
10. ^ Benson, Elizabeth, The Mochica: A Culture of Peru. New York, NY: Praeger Press. 1972
11. ^ Berrin, Katherine & Larco Museum. The Spirit of Ancient Peru:Treasures from the Museo Arqueológico Rafael Larco Herrera. New York: Thames and Hudson, 1997.

References

• Bilger, Burkhard. "Spider Woman". The New Yorker, 5 March 2007, pp. 66-73.
• W. S. Bristowe (1976). The World of Spiders. Taplinger Pub Co. ISBN 0-8008-8598-8.
• Crompton, John. The Life of the Spider, Mentor, 1950.
• Hillyard, Paul. The Book of the Spider, Random House, New York, 1994.
• Kaston, B. J. How to Know the Spiders, Dubuque, 1953.
• Main, Barbara York. Spiders, Collins (The Australian Naturalist Library), Sydney, 1976.
• Ubick, Darrell; Pierre Paquin, Paula E. Cushing, and Vincent Roth. Spiders of North America: an Identification Manual, American Arachnological Society, 2005.
• Wise, David H. "Spiders in Ecological Webs." Cambridge University Press. Great Britain: 1993.

External links

Wikimedia Commons has media related to:

Araneae

Wikispecies has information related to:

Spiders

General

• The Arachnology Home Page: Araneae - Spiders
• Spider info by Ed Nieuwenhuys
• Deutsche Arachnologische Gesellschaft e. V. - German Arachnologic Society (EN/DE)
• Wikia has a wiki about this topic: spiders
• Spider Pest Control Information - National Pesticide Information Center
• Spider webs in space
• Indoor Spiders of New England Harvard University

Regional

• Australian spiders
• List of spiders found in Great Britain
• University of Southern Queensland’s Find-a-spider guide
• Watson, L., and Dallwitz, M.J. 2004 onwards. The families of spiders represented in the British Isles.
• Czech spiders with photos
• Spiders of the Caucasus (caucasus-spiders.info)
• Spiders of Wisconsin

Morphology

• Histology of Salticid Spiders

Taxonomy

• Platnick, N.I. 2005. World Spider Catalog
• Canadian Arachnologist & Nearctic Spider Database
• Total number of described spider genera and species

Pictures

• Tarantulas.us - Gallery - The largest photo gallery of all tarantula’s species.
• Spiders of North America Library of reference quality large format photographs with taxonomy and descriptions.
• Free Nature Photos, spiders
• Macro Photography - Pictures of spiders, image gallery (commercial, but very good pictures)

Other

• Webs made by spiders fed on drug-dosed flies
• Spiders Research on Spiders from Science Daily.
• University of California evaluations of spider bite severity
• http://www.tarantulatour.com

[hide] Spiders
Arachnology	Evolution · Behavior · Identifying · Cannibalism · Ballooning · Spider webs in space · List of types · Blind spiders
Taxonomy	Mesothelae · Opisthothelae · Mygalomorphae · Araneomorphae · Lists of spider species
Anatomy	Arthropod leg · Book lung · Cephalothorax · Chelicerae · Cheliceral fang · Cribellum · Epigyne · Exuvia · Opisthosoma · Pedipalp · Scopula · Silk · Spinneret · Urticating hair · Web · Web decorations
Human interaction	Spider bite · Arachnophobia · Cultural depictions
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Brown Recluse Spider

HYG-2061-04

Susan C. Jones, Ph.D.
Assistant Professor of Entomology
Extension Specialist, Household & Structural Pests

The brown recluse spider is uncommon in Ohio. Nonetheless, OSU Extension receives numerous spider specimens that homeowners mistakenly suspect to be the brown recluse. Media attention and public fear contribute to these misdiagnoses.

The brown recluse belongs to a group of spiders that is officially known as the "recluse spiders" in the genus Loxosceles (pronounced lox-sos-a-leez). These spiders are also commonly referred to as "fiddleback" spiders or "violin" spiders because of the violin-shaped marking on the top surface of the cephalothorax (fused head and thorax). However, this feature can be very faint depending on the species of recluse spider, particularly those in the southwestern U.S., or how recently the spider has molted.

The common name, brown recluse spider, pertains to only one species, Loxosceles reclusa. The name refers to its color and habits. It is a reclusive creature that seeks and prefers seclusion.

Distribution

The brown recluse spider and ten additional species of Loxosceles are native to the United States. In addition, a few non-native species have become established in limited areas of the country. The brown recluse spider is found mainly in the central Midwestern states southward to the Gulf of Mexico (see map). Isolated cases in Ohio are likely attributable to this spider occasionally being transported in materials from other states. Although uncommon, there are more confirmed reports of Loxosceles rufescens (Mediterranean recluse) than the brown recluse in Ohio. It, too, is a human-associated species with similar habits and probably similar venom risks (unverified).

Identification

not actual size

Recluse spiders have six eyes that are arranged in pairs.

In the mature brown recluse spider as well as some other species of recluse spiders, the dark violin marking is well defined, with the neck of the violin pointing toward the bulbous abdomen. The abdomen is uniformly colored, although the coloration can range from light tan to dark brown, and is covered with numerous fine hairs that provide a velvety appearance. The long, thin, brown legs also are covered with fine hairs, but not spines. Adult brown recluse spiders have a leg span about the size of a quarter. Their body is about 3/8 inches long and about 3/16 inches wide. Males are slightly smaller in body length than females, but males have proportionally longer legs. Both sexes are venomous. The immature stages closely resemble the adults except for size and a slightly lighter color. Whereas most spiders have eight eyes, recluse spiders have six eyes that are arranged in pairs in a semicircle on the forepart of the cephalothorax (see close-up view). A 10X hand lens or microscope is needed to see this diagnostic feature. In order to determine the exact species of Loxosceles, the spider’s genitalia need to be examined under a high-power microscope. This requires the skills of a spider expert.

Life Cycle and Habits

Egg laying primarily occurs from May through July. The female lays about 50 eggs that are encased in an off-white silken sac that is about 2/3-inch diameter. Each female may produce several egg sacs over a period of several months. Spiderlings emerge from the egg sac in about a month or less. Their development is slow and is influenced by weather conditions and food availability. It takes an average of one year to reach the adult stage from time of egg deposit. Adult brown recluse spiders often live about one to two years. They can survive long periods of time (about 6 months) without food or water.

The brown recluse spider spins a loose, irregular web of very sticky, off-white to grayish threads. This web serves as the spider’s daytime retreat, and it often is constructed in an undisturbed corner. This spider roams at night searching for insect prey. Recent research at the University of Kansas indicates that the brown recluse spider is largely a scavenger, preferring dead insects. Mature males also roam in search of females.

Brown recluse spiders generally occupy dark, undisturbed sites, and they can occur indoors or outdoors. In favorable habitats, their populations are usually dense. They thrive in human-altered environments. Indoors, they may be found in attics, basements, crawl spaces, cellars, closets, and ductwork or registers. They may seek shelter in storage boxes, shoes, clothing, folded linens, and behind furniture. They also may be found in outbuildings such as barns, storage sheds, and garages. Outdoors, brown recluse spiders may be found underneath logs, loose stones in rock piles, and stacks of lumber.

The brown recluse spider is not aggressive, and it normally bites only when crushed, handled or disturbed. Some people have been bitten in bed after inadvertently rolling over onto the spider. Others 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.

Bite Symptoms

The physical reaction to a brown recluse spider bite depends on the amount of venom injected and an individual’s sensitivity to it. Some people are unaffected by a bite, whereas others experience immediate or delayed effects as the venom kills the tissues (necrosis) at the site of the bite. Many brown recluse bites cause just a little red mark that heals without event. The vast majority of brown recluse bites heal without severe scarring (http://spiders.ucr.edu/avoidbites.html).

Initially, the bite may feel like a pinprick or go unnoticed. Some may not be aware of the bite for 2 to 8 hours. Others feel a stinging sensation followed by intense pain. Infrequently, some victims experience general systemic reactions that may include restlessness, generalized itching, fever, chills, nausea, vomiting, or shock. A small white blister usually initially rises at the bite site surrounded by a swollen area. The affected area enlarges and becomes red, and the tissue is hard to the touch for some time. The lesion from a brown recluse spider bite is a dry, blue-gray or blue-white, irregular sinking patch with ragged edges and surrounding redness–termed the "red, white, and blue sign." The lesion usually is 1½ inches by 2¾ inches or smaller. Characteristics of a bite are further discussed at http://www.amednews.com/free/hlsa0805.

The bite of the brown recluse spider can result in a painful, deep wound that takes a long time to heal. Fatalities are extremely rare, but bites are most dangerous to young children, the elderly, and those in poor physical condition. When there is a severe reaction to the bite, 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. The sunken, ulcerating sore may heal slowly up to 6 to 8 weeks. Full recovery may take several months and scarring may remain.

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. Necrotic wounds can result from a variety of agents such as bacteria (Staphylococcus, "flesh-eating" Streptococcus, etc.), viruses, fungi, and arthropods (non-recluse spiders, centipedes, mites, ticks, wasps, bedbugs, kissing bugs, biting flies, etc.). Necrotic conditions also can be caused by vascular and lymphatic disorders, drug reactions, underlying diseases states, and a variety of other agents. An annotated list of conditions that could be mistaken for a brown recluse spider bite is available at http://www.ama-assn.org/amednews/2002/08/05/hlsa0805.htm. Misdiagnosis of lesions as brown recluse bites can delay appropriate care.

First Aid

If bitten, remain calm, and immediately seek medical attention (contact your physician, hospital and/or poison control center). 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, for positive identification by a spider expert. A plastic bag, small jar, or pill vial is useful and no preservative is necessary, but rubbing alcohol helps to preserve the spider.

An effective commercial antivenin is not available. The surgical removal of tissue was once standard procedure, but now this is thought to slow down wound healing. Some physicians administer high doses of cortisone-type hormones to combat hemolysis and other systemic complications. Treatment with oral dapsone (an antibiotic used mainly for leprosy) has been suggested to reduce the degree of tissue damage. However, an effective therapy has not yet been found in controlled studies.

Control

Control of indoor infestations of the brown recluse spider can take a long time (6 months or more) and can be difficult because humans have a very low tolerance for this pest, it tends to be widely dispersed within infested buildings, and it seeks secluded sites. Control of spiders, including the brown recluse, is best achieved by following an integrated pest management (IPM) approach. IPM involves using multiple approaches such as preventive measures, exclusion, sanitation, trapping, and chemical treatment when necessary.

Preventing spider bites

• Shake out clothing and shoes before getting dressed.
• Inspect bedding and towels before use.
• Wear gloves when handling firewood, lumber, and rocks (be sure to inspect the gloves for spiders before putting them on).
• Remove bedskirts and storage boxes from underneath beds. Move the bed away from the wall.
• Exercise care when handling cardboard boxes (recluse spiders often are found in the space under folded cardboard flaps).

Exclusion

• Install tight-fitting screens on windows and doors; also install door sweeps.
• Seal or caulk cracks and crevices where spiders can enter the house.
• Install yellow or sodium vapor light bulbs outdoors since these attract fewer insects for spiders to feed upon.
• Tape the edges of cardboard boxes to prevent spider entry.
• Use plastic bags (sealed) to store loose items in the garage, basement, and attic.

Sanitation

• Remove trash, old boxes, old clothing, wood piles, rock piles, and other unwanted items.
• Eliminate clutter in closets, basements, attics, garages, and outbuildings.
• Do not stack wood against the house.
• Clean up dead insects that the brown recluse spider can feed on.

Non-chemical control

• Use sticky traps or glueboards to capture spiders.
• Dust and vacuum thoroughly to remove spiders, webs, and egg sacs (dispose of the vacuum bag in a container outdoors).
• Use a rolled up newspaper or fly swatter to kill individual spiders.

Insecticides

There are many labeled pesticides for spider control. Some are labeled for homeowner use, while others are labeled only for the licensed, certified pesticide applicator. It would be prudent to enlist the services of a professional pest management company when dealing with an indoor infestation of the brown recluse spider.

Research indicates that recently developed pyrethroids (e.g., cyfluthrin, cypermethrin, etc.) are particularly effective against brown recluse spiders. Wettable powders and microencapsuled "slow-release" formulations of these chemicals provide residual activity and are preferable to using emulsion-type sprays. Insecticide treatments should be applied so that the chemical contacts as many spiders and webs as possible. Residual liquid sprays should be applied to the outside perimeter of the home (including under eaves, patios, and decks; behind window shutters), baseboards, undisturbed corners, and other suspected spider harborages. Residual dusts should be applied to voids and inaccessible areas where spiders may hide. Aerosol flushing agents such as pyrethrins, though ineffective by themselves in providing control, can cause spiders to move about so that they contact treated surfaces

Protection, aggression and grip

• Barbed hairs
• Spider sounds
• Spiny legs
• Getting a grip

Red-kneed Tarantula, Brachypelma smithi, showing irritant hairs on abdomen. Photo: R Bolzan © Australian Museum.

Barbed hairs
American tarantulas use the barbed irritant hairs (urticating hairs) on the abdomen to protect themselves against predators like lizards and mammals. When threatened, these spiders brush their back legs rapidly across the back of the abdomen. This sends clouds of loosely attached barbed hairs into the eyes, nose or mouth of the predator chasing them. The spider escapes while its pursuer is distracted by the highly irritant hairs.

A mass of barbed hairs.
Photo: S Lindsay © Australian Museum.

One type of barbed hair.
Photo: S Lindsay © Australian Museum.

A Whistling Spider (Selenocosmia crassipes) stridulating in a defensive pose. Photo: © R Morrison.

Spider sounds
Some spiders make noises to attract mates or as warning signals. Australian tarantulas are called Whistling Spiders because they ‘whistle’ when threatened. To make the whistling or whirring sound, they rapidly rub together modified hairs on their mouthparts. This is called stridulation. Both male and female whisting spiders have these organs. The sound may help scare off predators like small carnivorous marsupials when the spiders are caught hunting out of their burrows.

A triangular Spider (Arcys) seizes flies with its strong and spiny front legs. Photo: © D Gray.

Spiny legs
Most spiders have strong, thick modified hairs called spines on the limbs. Spines are often more numerous and larger on the front legs. They assist in capturing and holding prey or in helping males hold females during mating.

The underside of the foot of this Trapdoor Spider (family Barychelidae) is covered with scopula hairs.
Photo: S Lindsay © Australian Museum.

Getting a grip
Spiders like tarantulas, huntsman and jumping spiders have densely packed hairs called scopulae on their feet (tarsal and metatarsal leg segments). Scopulae give the legs lots of clinging power and allow the spiders to walk easily on smooth surfaces like tree trunks, leaves, ceilings and window glass. They also help these spiders to hold on to struggling prey.

There are two types of scopulae - brushes and claw tufts. Both may have hundreds of scopulate hairs. Each scopulate hair may have hundreds of little branches or ‘end feet’. As a result, there can be more than a million of these tiny ‘end feet’ in contact with a surface, providing enormous frictional clinging power. This effect is aided by the capillary forces of an extremely thin layer of water on most surfaces.

Some of the hundreds of scopulate hairs.
Photo: S Lindsay © Australian Museum.

The tiny ‘end feet’ covering the surface of each scopulate hair.
Photo: S Lindsay © Australian Museum

Sensing the world with hairs and pits
The hairy foot. Click here for a larger image. All spiders are hairy - like us. Spider hairs are part of the hard outer cuticle (the spider’s ’skin’). Unlike us, spiders use their hairs (which are often greatly modified) to perform an amazing variety of tasks - for sensing their world, in courtship displays, for moving around, and in defence and prey capture.

Sight is our most important sense. However, most spiders have very poor eyesight and many are active during the dark night hours. With a few notable exceptions, their sense of the world is obtained through specialised sensory hairs and pit-like sense organs in the cuticle. These hair and pit sensillae are especially associated with the spider’s limbs and mouthparts. Connected at their bases to sensory nerves, they provide spiders with the sensory experience and feedback needed to survive and function in their world.

Hinged, touch-sensitive hairs on the legs help the spider to move freely about its terrain and are important in interactions ranging from mating to prey capture. Chemically sensitive, hollow-tipped hairs found at the ends of the limbs and on the mouthparts are the spider’s tasting organs - those on the pedipalps are used to sense the chemicals associated with mate recognition.

Another stimulus to which spiders are incredibly sensitive is vibration. Vibrations transmitted through air, substrate surfaces and even water can be sensed by spiders.

Air vibrations and currents are detected by slender, vertical hairs called trichobothria, usually found on the upper surface of the three outermost limb segments. These hairs are easily deflected and their ‘ball and socket’ basal hinge allows them to respond to air movements coming from any direction. This high sensitivity to air-borne vibrations can alert the spider to the wing beats of an approaching moth or fly, or the presence of a wasp predator.

Substrate vibrations, induced in web, leaf , ground or water surfaces by nearby disturbances (such as prey, mate or predator movement), cause slight movements in a waiting spider’s limbs. These movements can be directionally sensed by tiny ’strain gauges’ in the cuticle called slit organs (or lyriform organs when several are grouped together, as at the tarsal-metatarsal joint) that react to any slight deformation of the cuticle. The sensitivity is such that spiders can readily distinguish prey movement vibrations from those of a courting male or the background noise of wind.

Slit organs are also somehow involved in the spider’s ability to ‘memorise’ directions, for example, the return route to its burrow after a hunting trip. A number of tiny ’slit organs’ placed around the bases of the silk spinning spigots on the spinnerets appear to be involved in the sensory monitoring of the movements of the spigots and the emission of silk during spinning, the control of which is still poorly understood.

Near the end of each limb is a tiny pit, dome or peg-like structure called the tarsal organ. They appear to function primarily as moisture and temperature detectors.

Internally placed joint receptors and external sensory hairs (usually short hairs adjacent to joint membranes or longer hairs that span joints) keep the spider informed of its limb positions (proprioception) during movement. This ensures that the spider moves in a coordinated way.

Spider Control Facts
Have Arachnophobia?  Contrary to the 1990 Steven Spielberg movie made popular by John Goodman as the "Exterminator" and Jeff Daniels as the "Doctor" most spiders are harmless.  The only distinguishable feature is that Spiders have a characteristic appearance which is easily recognized by most people. They possess eight legs which immediately separate them from insects, which have only six legs. Spiders lack wings and antennae. Their bodies have but two regions - a cephalothorax (fused head and thorax) and an abdomen. Young spiders, or spiderlings, resemble the adults except for size and, sometimes, coloration. All spiders have a pair of jaw-like structures, called chelicerae. At the end of each is a hollow, claw-like fang. Each fang has a small opening in the end through which venom is injected into the prey. Spinnerets, located at the tip end of the abdomen, are silk spinning glands used for web making.

Many species of spiders are common household pests in the United States. Certain common household spiders spin webs over lamps, in corners and in basements. This creates an unsightly situation but causes no real harm. Remember that every "cobweb" was made by a spider. Although all spiders use venom when they bite and kill their prey, the black widow and the brown recluse spiders are the only North American species consistently dangerous to humans. Even though there is generally little danger of complications from spider bites, you should advise all spider bite victims to take the spider specimen with them (if possible) when consulting their physician.

Under most conditions outdoors, spiders are considered beneficial because they feed on insects. However, they are undesirable to most homeowners when indoors, and the unsightly webbing spiders use to catch insect prey usually outweigh this beneficial behavior.

Many spiders are associated with moisture and, therefore, are found in basements, crawl spaces, and other damp parts of buildings. Others live in warm, dry places so are found in sub floor air-vents, in upper corners of rooms or in attics. Most species hide in cracks, darkened areas, or other retreats which they construct of silk.

Poisonous Spiders
Black Widow Spider / Brown Widow Spiders

Widow Spiders

The black and brown widows are widely distributed over the warmer portions of the United States. Females are easily identified because of their globular, shiny black or brown abdomen with two reddish or yellowish triangles on the underside. These reddish or yellowish triangles form a characteristic hourglass marking. The abdomen is about 1/4 inch in diameter but may be as large as 1/2 inch when the female is full of eggs. Males are much smaller and lighter-colored, with light streaks on their abdomens.

Left - Female Black Widow Spider         Right - Brown Widow

Brown Widow w/Multicolored Top

The widow’s web is an irregular mass of fibers with a small central area to which the spider retreats while waiting until its prey becomes ensnared. These webs are frequently constructed underneath boards, stones, or the seats of outdoor privies. They are also found along foundation slabs, behind shrubs and especially where brick or wood siding extends close to ground level. This spider does not usually enter residences.

Widow spider venom contains toxins that are neurotoxic (affects the nervous system). The severity of a person’s reaction to the bite depends on the area of the body where the bite occurs; the person’s size and general sensitivity; the amount of venom injected; depth of bite; seasonal changes (in venom potency); and temperature. The bite produces a sharp pain similar to a needle puncture. The pain usually disappears rapidly. Local muscular cramps are felt 15 minutes to several hours after the bite, spreading and becoming more severe as time passes. The venom then grows weak, tremors develop, and the abdominal muscles show a board-like rigidity. Respiration becomes spasmodic and the patient is restless and anxious. During this period, a feeble pulse, cold skin, labored breathing and speech, light stupor, and delirium may be noted. Convulsions and death may result with some victims,  especially if the person is sensitive to the venom and no treatment is received. An anti-venom specific for the black or brown widow is readily available to most physicians.

Brown Recluse Spider

The brown recluse spider, (loxosceles reclusa), can also inflict a very dangerous bite. The initial pain associated with the bite is not intense, and is generally less troublesome than a bee sting. Within 8 to 12 hours the pain becomes quite intense, and over a period of a few days a large ulcerous sore forms. This sore heals very slowly and often leaves a large, ugly disfiguring scar.

Brown Recluse Bite and Infection
Warning - Pictures Are Graphic !

          Subject Unknown - Infection Time 6-8 weeks.
Click On Each For A Larger Image

The brown recluse is soft-bodied and secretive species found in homes and other outbuildings. The adult body varies from 1/3- to 1/2inch in length, with the arrangement of the legs producing a larger overall size of 1 inch diameter or greater. The body is yellow to dark brown, and has a rather distinctive darker brown violin shaped mark on the top of the cephalothorax.  Recluse Spiders are often colored tan, but can be dark brown to almost white in appearance.

             
Brown Recluse Spider                                                 Click For Larger Image

The Brown Recluse Spider has been widely reported in the southern, western, and mid western United States, and is a particularly serious pest in Oklahoma, Missouri, and surrounding states. It is usually found indoors, particularly in bathrooms, bedrooms, closets, garages, basements, and cellars. In homes with forced hot-air heating and air conditioning and often above-ceiling ductwork, brown recluse spiders are commonly found harboring in or around the ductwork or registers. They may also be present in attic areas or other locations above the ceiling. They are also commonly found in cluttered closets or basements, and in outbuildings where miscellaneous items are stored. The web is not elaborate and is best described as an off white to gray, nondescript type of webbing. The spider is not aggressive and usually retreats to cover when disturbed. Most bites occur when a person crushes the spider while putting on old clothes that have been hanging in a garage, or by rolling on the spider while asleep in bed.

The best method of treatment for Brown Recluse Spiders is to first carefully inspect all areas (using leather gloves and flashlight) that are suspected of harboring them.   The BugBuster Vacuum is perfect for capturing them during an inspection or even for collection purposes.  Then after careful inspection, treat all areas with a wettable powder insecticide such as Demon WP.  Baseboards, corners of rooms, closets, under and behind furniture, window sills, etc, should all be carefully treated.  Attics and sub areas can be treated or dusted with TriDie. BioCare Spider Traps, Trapper LTD glue traps or Insect stick alls can also be used to trap Brown Recluse and monitor movement and population numbers.

As previously mentioned the Brown Recluse Spider is usually found indoors, especially in bathrooms, bedrooms, closets, garages, basements, and cellars. They may also be present in attic areas, or other locations above the ceiling. They may also be found in out-buildings. Their web is not very elaborate and is best described as an off-white to gray, nondescript webbing. Most bites occur when a person crushes the spider while putting on clothes that may have been hanging for some time, or by rolling on the spider while asleep in bed. Gardeners should wear gloves and be especially alert when handling leaves or bark mulch.

Non Poisonous Spiders

Tarantula’s, Jumping Spiders, Wolf Spiders and Garden Spiders are victims of a so-called spider phobia and are considered to be armed and dangerous simply because the possess the same spider shape and characteristics as the brown recluse and black widow.     They are hairy, large and formidable, but their bite is less harmful than a bee sting.  Some people, however, are extremely allergic to spider venom, so if you are bitten and have an adverse reaction, don’t hesitate to see your physician immediately.

Tarantula

Many people have tarantula’s as pets.  Although this may sound fun to some people, tarantula’s although shy and timid most of the time will bite if angry or provoked. 

Tarantula

Garden Spider

The garden spider is sometimes called a yellow sac spider - although the yellow sac spider is a completely different species.  The garden spider weaves a beautiful web and is the best looking of all the spiders.

Garden Spider

Wolf Spider

We’re not sure that the wolf spider looks like a wolf.

Wolf Spider

Hunting Spider

The hunting spider hunts for insects, not people.

Hunting Spider

Jumping Spider

Jumping spiders can jump, as most spiders can, although nobody is for sure how far or high.

Jumping Spider

Daddy Long Legs

Daddy Longlegs are not true spiders.  They are spider like arachnids, belonging to the same class (arachnid) as spiders, ticks, scorpions, and mites.  Daddy Longlegs, also known as Harvest Spiders, belong to a different order than spiders, that of Opilliones.  Spiders belong to the order Araneae. The daddy long legs get it’s name because their legs can grow to be over 12" long.  (April Bailey)

Daddy Long Legs

Spider Control

If spiders are breeding indoors or if outdoor species are migrating indoors, residual insecticide applications of Demand or Demon WP can be used. All areas where the spiders have been found should be treated, paying particular attention to dark corners of rooms and under furniture.  Dusts such as or Drione or TriDie may be especially useful for treating crawl spaces and attics. Wettable powder or microencapsulated formulations such as Demand or Demon WP will generally give somewhat better and longer residual action on most surfaces.  The use of glue type traps such as the BioCare Spider Traps or Trapper LTD indoors works well to trap spiders behind furniture, under beds, in closets, etc.

Outdoor treatment is necessary to control spiders which are migrating inside or to eliminate spiders on porches, under eaves, and other areas on the outside of the building. Spiders often become particularly numerous on the exterior surfaces of homes and buildings built near lakes. They spin webs to catch and feed on the many flying insects which come out of the lake.

Chronic spider problems can be very difficult to manage as there are few good management options except reducing night lights (which attract so many flying insects) and applying residual insecticide treatments at every few weeks.  Dr. T’s Cobweb Eliminator works well around boat docks, eaves, etc. to stop spiders from spinning their webs.  Spider fecal droppings can disfigure fiberglass boats or latex painted surfaces. Occasionally, residual treatments using a long lasting insecticide is necessary to eliminate heavy infestations. The residual insecticides such as Demand or Demon WP can be used indoors as well as outdoors.. 

The Webduster can be used to remove spider webs from eaves, doorways, window sills, corner of rooms, garages, etc.  It is the perfect companion when using Dr. T’s Cobweb Eliminator.  When removing spider webs it is important to remember to also remove and destroy the egg sacs.  It may be a better idea in some cases to spray the area (eaves) with a residual insecticide first to kill the spiders and also the eggs, let the area dry, and then remove the webs and egg sacs.  Whatever method you prefer, be sure to not disrupt live spiders to the point where the jump or lunge at you during your web removal process.  Protective clothing and eye protection is also recommended to help protect against spider bites and exposure to the products being applied overhead which can result in drift.

Cobweb Removal Using The Webduster

Recommended Products:

Indoors - Liquid sprays such as Demand or Spiders must be killed by spraying directly on contact. Residual sprays are ineffective since spiders do not absorb chemicals through their feet or legs as cockroaches do.  Dust formulations such as Drione or TriDie are very effective in attic areas and basement areas.Demon WP. 

BioCare Spider Traps, Insect Stick all’s, Trapper LTD’s - Place Stick all’s under and behind furniture to trap, catch and monitor spider infestations, especially infestations of Brown Recluse and Black Widow Spiders.

Vacuuming using the BugBuster Vacuum  and removal of webs and egg sacs. Removal of clutter and other sanitation steps directed at conditions favoring spiders and insect populations.

Cobweb removal using the  Webduster.

Outdoors - Liquid broadcast spray such as Demand or Demon WP.  Cobweb removal using the  Webduster and Dr. T’s Cobweb Eliminator works great on Boat Docks and homes and buildings located near lakes and other spidery areas.   Dr. T’s Cobweb Eliminator is a natural product that prevents spiders from spinning webs.

Spiders belong to the class of mainly terrestrial Arthropods known as Arachnida. Medically significant classes of arachnids include spiders, ticks/mites and scorpions. Unfortunately through myths, legends and nowadays media, spiders have gained a reputation of being dangerous and harmful, and in some people instil a psychological fear known as arachnophobia. In reality, very few are dangerous to man and media reports exaggerating the dangers of spider bites are far out of proportion to the actual threat they pose.

What spiders bite and may be harmful to man?

The most important groups of spiders based on the medical consequences if bitten by one are shown in the table below.

The venom produced by spider bites is generally either neurotoxic or cytotoxic. Web dwellers tend to have neurotoxic venom and non-web dwellers cytotoxic venom. Spiders of the Latrodectus genus produce neurotoxic venom, while the violin spider and yellow sac spider produce cytotoxic venom.

Spiders

White tailed spider

What are the signs and symptoms of spider bites?

The signs and symptoms of a spider bite depend on many factors, these include:

• Neurotoxic or cytotoxic venom
• Amount of venom injected
• Health of the patient (e.g. any allergies)
• Age of the patient (small children and elderly are more adversely affected)
• Site of the bite

The signs and symptoms from a bite from a spider with neurotoxic venom differ to those produced by a spider with cytotoxic venom. The severity of the symptoms depends on the species of spider as the symptoms of bites from different species of Loxosceles can range from unremarkable (requiring no care), localised (usually self-healing), dermonecrotic (slow-healing ulcerated lesion requiring treatment), to systemic (vascular, renal damage and sometimes life-threatening).

What are the dermatological features of spider bites?

Widow spider bites

The skin around the site of the bite is red and two fang marks may be visible where the skin was penetrated. In untreated cases a rash may develop after several days. Systemic symptoms are of more diagnostic value.

Violin or recluse spider bites

The dermatological features of these spider bites depend on the severity of the bite. In self-healing wounds, the bite site gets no worse than being swollen and red. With more serious bites a “bull’s eye” wound may form. This is characterised by a central red swollen blister that is separated from a peripheral bluish region by a white zone of firm swelling. If the bite turns a purplish colour within the first few hours, this usually indicates severe localised tissue death (necrosis) may occur. Over days the blister forms a scab, which hardens and falls off to leave behind an ulcerated depression. Healing can take weeks to months.

Interestingly, it appears that bites that become systemic do not also develop necrotic wounds. It is thought that in necrotic wounds the venom is localised in the tissue whereas in systemic reactions the venom is distributed quickly throughout the body without any localised effects.

Other spider bites

Spider-bite (presumed to be due to white-tailed spider)

Day 1

Day 2

Day 3

What is the treatment for spider bites?

One of the most important aspects in treating spider bites it to try and identify the offending spider. The venom of spider bites is quite variable hence identification of the spider can be of value in determining the management of the condition.

General measures that should occur after a spider bite include:

• Wash the area well with soap and water
• Apply a cold flannel or ice pack wrapped in cloth to the site
• Give paracetamol for pain
• Seek immediate emergency care for further treatment

Depending on identification of the offending spider and the severity of the bite treatment may include:

• Muscle relaxants
• Stronger pain relievers
• Antibiotics to prevent infections and antihistamines to reduce swelling
• Supportive care
• Antivenin

Specific treatment for bites from certain spiders include:

• Intravenous calcium gluconate alternating with methocarbamol to relieve muscle cramps caused by spiders belonging to the Latrodectus genus (e.g. black widow).
• Antivenin is available for bites by spiders of the Latrodectus and Loxosceles genera and is very effective if given soon after the bite.
• Hydroxyzine (antihistamine) may be given to alter the necrotic lesion of bites from spiders of the Loxosceles genus.
• It is possible that systemic steroids may be of benefit.

Main Symptoms

• Bite from a spider seen on the skin.
• Onset of bite symptoms (redness, pain, swelling) and a spider is seen in close proximity.

Types of Spider Bites

1.  Black Widow Spider Bite

• A shiny, jet-black spider with long legs (total size 1 inch).
• A red (or orange) hourglass-shaped marking on its under-side.
• Causes immediate local mild pain, swelling and occasionally 2 fang marks.
• Severe muscle cramps are present by 1 to 6 hours, and last 24 to 48 hours.
   
• Rarely causes death (exception: bitten by several spiders or small child is bitten).
• Note: many are dry bites because the fangs are small.

2.  Brown Recluse Spider Bite

• A brown spider with long legs (total size 1/2 inch).
• A dark violin-shaped marking on top of its head.
• Causes local pain and delayed blister formation in 4 to 8 hours.
• The center becomes bluish and depressed (crater-like) over 2 to 3 days.
• Skin damage may require skin grafting in 10% of cases.
• Systemic symptoms such as fever, vomiting, muscle pain can occur (but no life-threatening symptoms).

3.  Non-dangerous Spider Bites

• More than 50 spiders in the U.S. have venom and can cause local, nonserious reactions.
• The bites are painful and mildly swollen for 1 or 2 days (much like a bee sting).
• Most single, unexplained, tender bites that occur during the night are due to spiders.

WHEN TO CALL YOUR DOCTOR FOR SPIDER BITE

Call 911 Now (your child may need an ambulance)If

• Difficulty breathing or swallowing. 

See More Appropriate Topic (instead of this one) If

• Not a spider bite, see INSECT BITE.
  (To go directly to this topic, click on the link following this document.)

Call Your Doctor Now (night or day)If

• Your child looks or acts very sick.
• Any black widow spider bite.
  FIRST AID for Black Widow Spider Bites:  Apply an ice cube or ice pack to the bite for 20 minutes to reduce the spread of the venom (no tourniquet).
• Abdominal pain, chest tightness or other muscle cramps.
• Bite pain is severe.
• Bite looks infected (red streaking from the bite area, yellow drainage).  (Note: infection doesn’t start until at least 24-48 hours after the bite.  Any redness in the first 24 hours is due to venom.)

Call Your Doctor Within 24 Hours (between 9am and 4pm) If

• You think your child needs to be seen.
• Bite starts to look bad (e.g. skin damage, blister or purplish - not just swelling).
• Bite pain persists for more than 2 days.

Call Your Doctor During Weekday Office Hours If

• You have other questions or concerns.

Parent Care at Home If

• Non-serious spider bite and you don’t think your child needs to be seen.

HOME CARE ADVICE FOR NONDANGEROUS SPIDER BITES

1. Cleansing:  Wash the bite thoroughly with soap and water.

2.  Meat Tenderizer:  Rub the bite area with a cotton ball soaked in a meat tenderizer solution for 20 minutes (Exception: avoid if near the eye).  If not available, apply an ice cube for 20 minutes.

3.  Pain Medicine:  Give acetaminophen (e.g. Tylenol) or ibuprofen as needed for pain.

4.  Expected Course:  Some swelling and pain for 1 to 2 days.  It shouldn’t be any worse than a bee sting.

5.  Call Your Doctor If:

• Severe bite pain persists for more than 2 hours after pain medicine.
• Abdominal pains or muscle spasms occur.
• Local pain lasts more than 2 days (48 hours).
• Bite begins to look infected.
• Your child becomes worse or develops any of the "Call Your Doctor" symptoms.

Disclaimer: This information is not intended be a substitute for professional medical advice. It is provided for educational purposes only. You assume full responsibility for how you choose to use this information. Pediatric HouseCall Online. Copyright © 2000-2003 Barton Schmitt, M.D.FAAP
Reviewed 8/2003

Revised 7/2002