Spider and Scorpion case Black widow spider (Lactrodectus hesperus) Black widows are notorious spiders identified by the colored, hourglass-shaped mark on their abdomens. Several species answer to the name, and they are found in temperate regions around the world. This spider's bite is much feared because its venom is reported to be 15 times stronger than a rattlesnake's. In humans, bites produce muscle aches, nausea, and a paralysis of the diaphragm that can make breathing difficult; however, contrary to popular belief, most people who are bitten suffer no serious damage—let alone death. But bites can be fatal—usually to small children, the elderly, or the infirm. Fortunately, fatalities are fairly rare; the spiders are nonaggressive and bite only in self-defense, such as when someone accidentally sits on them. These spiders spin large webs in which females suspend a cocoon with hundreds of eggs. Spiderlings disperse soon after they leave their eggs, but the web remains. Black widow spiders also use their webs to ensnare their prey, which consists of flies, mosquitoes, grasshoppers, beetles, and caterpillars. Black widows are comb- footed spiders, which means they have bristles on their hind legs that they use to cover their prey with silk once it has been trapped. To feed, black widows puncture their insect prey with their fangs and administer digestive enzymes to the corpses. By using these enzymes, and their gnashing fangs, the spiders liquefy their prey's bodies and suck up the resulting fluid. Giant desert hairy scorpion (Hadrurus arizonensis) Hadrurus arizonensis is distributed throughout the Sonora and Mojave deserts. In Mexico, the species' range flanks the Gulf of Californiain Sonora and Baja California Norte. In the United States, it is found in the western two thirds of Arizona, the Colorado Desert and Mojave Desert regions of southern California, southern Nevada, and extreme southwestern Utah. It is a burrowing scorpion, but is commonly found under rocks containing moisture. Its diet consists of large insects, spiders, and smallvertebrates.[2] This is an aggressive and active scorpion, which, as with all scorpions, is nocturnal. Like all scorpions, the giant desert hairy scorpion gives birth to live young, which remain on the mother's back for a week or more before leaving. Although this scorpion is big, its venom is not very potent, and its sting is commonly perceived to be about as painful as a honeybee's sting. The venom has an LD50 value of 168 mg/kg.[3] However, an allergic reactionto its venom can be fatal; symptoms can include difficulty breathing, excessive swelling, and prolonged pain. • Desert hair scorpions are one of only a few animals that phosphoresce (video) under ultraviolet light produced by a black light. This is due to fluorescent chemicals in the cuticle. One known fluorescent component is beta-carboline. • They can detect air movement up to a foot away through the use of their sensory hairs on their pedipalps. The tips of theirs legs have small organs that can detect ground vibrations. • When they are agitated they will raise their body higher off the ground and open their pincers as well as lift their tail. When they are calm they will lie flat and look relaxed. • When scorpions mate they perform a dance with their mate (video). The goal of this dance is for the male to place a spermatophore on the ground and drag the female over it so that she will take it into her body. When her babies hatch she will carry them around on her back. Giant redheaded centipede (Scolopendra heros) All centipedes are believed to be predators. Their diet is composed primarily of small arthropods, although some scolopendromorphs have been found feeding on toads, small snakes, and other vertebrates. Moths are a preferred diet for captive giant redheaded centipedes. The prey is captured and killed or stunned with the poison claws. Poison glands are located in the basal segments of the claws or fangs, sometimes called maxillipeds. Each gland drains its toxic contents through a small opening near the tip of the fang. In the mid 1920s, Dr. Baerg tested the effect of the venom by inducing a centipede to bite one of his little fingers, leaving the fangs inserted for about four seconds. The bite was followed by a sharp and strictly local pain, which began to subside noticeably after about 15 minutes. In about two hours the pain was only very slight, but there was a general swelling in the finger. Three hours after the bite, most symptoms had disappeared. Scolopendra heros is purported to make tiny incisions with its legs while walking across human skin. When the animal is irritated, a poison is supposedly produced near the base of each leg and dropped into the wounds causing inflammation and irritation. Bites are not fatal but may cause severe swelling and irritation for hours. If you are bitten, seek medical attention if the swelling worsens or other symptoms occur. This species might also make tiny cuts with its legs while walking across human skin, into which an irritating venom is secreted. Salt Lake County brown tarantula (Aphonopelma iodius) The teddy bear of the desert, these harmless fuzzy darlings live much longer than you might think -- up to 25 years for a female and about half that for a male! Tarantulas aren't the fastest runners. Their primary defense is the irritating hairs on their abdomens. When chased or frightened, they can use a back leg to brush these hairs into the eyes or mouth of a predator. In the late summer, you're likely to see tarantulas wandering in the foothills. They aren't migrating. They are mature males looking for females, with little interest in food or their own safety...just mating. In spite of their fearsome appearance, tarantulas are harmless to humans and large pets (e.g., dogs and cats). Their venom is of no medical significance, and, nobody has ever died from such a bite. Most people compare the bite to that of a bee sting and experience no lasting ill-effects other than mild to moderate pain and slight swelling at the site of the bite. Salt Lake County Brown Tarantula are the largest spiders in North America. They are typically two to three inches long and are covered in fine hair ranging in color from tan to dark brown. They have a dark triangle surrounding the eye turret on the carapace which is a diagnostic tool for recognizing this tarantula. They live in holes covered in web. The male follows the sent of a female tarantula to the receptive female's burrow, which she has typically excavated in dry, sandy soil and lined with silk webbing. To alert the female of his presence, the male taps one of his legs against the ground until the female emerges. The male must then participate in a dangerous mating dance, wherein he fends off the female, who wishes to devour him, by using hooks on his front legs. Aphonopelma are arguably the most speciose lineage of spiders, comprising of 121 genera and 939 described species. There has been an over-description of the Aphonopelma species resulting in a nomenclatural and taxonomic nightmare. Brown recluse spider (Loxosceles reclusa) The bite of the brown recluse spider is often not immediately painful, although a slight stinging sensation may be felt. This spider’s venom includes a neurotoxic component, but the principal concern is its necrotic or cytotoxic properties, which cause it to destroy the tissue where it is injected. About seven hours after a bite, a small blister-like sore appears that will grow in size. There may be a generalized or systemic body reaction in sensitive individuals. Symptoms include chills, fever, bloody urine, fatigue, jaundice, pain in the joints, nausea, rash, and in extremely rare cases, convulsions and death. The amount of damage depends on the amount of venom injected. The damaged area may be the size of a dime or as large as 20 centimeters in diameter. Affected tissue becomes gangrenous, turns black, and eventually sloughs off, leaving a depression in the skin. Healing is slow and scar tissue results from the wound. Healing may take six to eight weeks or require up to a year if the wound is large. Hobo spider (Eratigena agrestis) Hobo spider bites are not known to be fatal to healthy humans. The necrosis in purported cases is similar to, but milder than, that caused by the brown recluse spider, and in severe cases can take months to heal. Other reported symptoms include intense headaches, vision abnormalities, and/or general feelings of malaise. These symptoms are not confirmed for the hobo spider bite, specifically due to lack of positive identification of the spider by an expert, and the Oregon Poison Center (affiliated with the Oregon Health & Science University) is attempting to gather definitive evidence regarding the validity of these reports as of September 2007. .