![]() ![]() Spider silk is the strongest fiber in nature, five times stronger than steel, yet 30 times thinner than human hair. Other species wait for prey to become entangled in webs they construct of silk produced from spinnerets located on the end of the abdomen. Many species lie in ambush, hidden in cracks, crevices and holes, or camouflaged on vegetation, waiting to strike at insects that venture too close. Others claim that fear of spiders comes to us because spiders are simply “creepy.” It’s true that many spiders creep along on their eight legs in search of prey that consists of insects and other arthropods including spiders. And spiders are rarely aggressive toward humans they bite only in self defense. Fewer still are the number of species capable of producing bites with complications more severe than the average mosquito bite or bee sting. While virtually all spiders use their fangs to inject venom, the fangs of many of the more than 3,500 spider species in the United States are incapable of penetrating human skin. Yet there are a couple of problems with this theory.įirst, “arachnophobia” affects only a few of us – why not all of us? If spider bites can seriously harm or kill us, why don’t we all have an innate fear of spiders? This leads to another problem with attempts to justify the fear of spiders: On the whole, spiders just aren’t that dangerous. It’s been suggested that because some spider bites may have resulted in negative consequences for our prehistoric ancestors, that fearing spiders is adaptive, as it helps us avoid debilitating consequences. ![]() Of course, most of the negative publicity spiders receive is undeserved. Fear of spiders ranks as one of our greatest phobias, along with fears of snakes, heights and public speaking. Additionally, the reaction of different individuals to the same amount and type of venom will vary widely.It can be said that no other “bug” generates as much fear as the spider. The amount of venom injected varies from almost none to a full dose, depending on the quantity of venom in reserve at the time of biting, the length of time the fangs are in the tissue and even the location of the bite. The reaction to a bite from these spiders can range from mild to severe, depending on the individual that is bitten and the amount of venom injected. Very few spider species are considered to be a threat to human health, but the bite of the black widow or brown recluse spider can be serious. Serious injuries or fatalities from spider bites are extremely rare. When a spider bite occurs, the victim is often unaware that it happened. Spiders do not attack and bite humans unless they are threatened or provoked in some way. While it is true that spiders will rush across their webs to investigate a vibration, this is just a natural hunting reaction to disturbance and should not be interpreted as aggressive behavior. People tend to fear spiders because they believe that spiders are aggressive and seek to bite humans. Most other species are considered nuisance pests when found in and around homes. The brown recluse spider and black widow spider are the only two spiders in Missouri that are considered to be serious threats to human health. Tarantulas are not very abundant in Missouri but are occasionally collected from the southern part of the state. These groups are distinguished by the size and shape of their bodies, the structure of the legs and other appendages, and the size and relative position of the eyes. Some of the more common groups include orb weavers, crab spiders, jumping spiders and wolf spiders. More than 300 different spiders occur in Missouri. ![]() Silk is used by spiders to make webs, construct egg sacs, line nests, wrap captured prey, or construct "balloons" with which to travel on air currents over large distances. These structures are used to produce silk. (See above.) Spinnerets are located on the posterior tip of the abdomen. Also located at the front of the cephalothorax are the pedipalps, appendages used for handling food. Four, six or eight eyes are located at the front of the cephalothorax. They have eight legs, no antennae or wings, and an unsegmented abdomen. Spiders have a body composed of two regions called the cephalothorax (head) and abdomen (body). Spiders are most closely related to scorpions, ticks and mites.
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