A more diagnostic feature of recluse spiders is their 6 eyes, arranged in pairs in a semicircle, which can be seen with the use of a good hand lens. However, the mark is not always distinct, so it should not be used as an identifying character. Recluse spiders can have a violin-shaped mark (with the neck of the violin pointing backward) on the top side of the head region (cephalothorax). Related native recluse species are found in California's southeastern deserts. While the brown recluse has occasionally been brought into California in household furnishings, firewood, and motor vehicles, there are no breeding populations in the state. reclusa, which does not occur in California. Recluse spiders of the genus Loxosceles include the well-known brown recluse spider, L. Typical symptoms of a bite include initial pain similar to a bee sting, redness, and sometimes swelling. Bites usually occur when the spider becomes trapped against a person’s skin in clothing or bedding. Yellow sac spiders can be seen running on walls and ceilings at night and quickly drop to the floor to escape if they are disturbed. This spider is light yellow and has a slightly darker stripe on the upper middle of the abdomen.The 8 eyes of this spider are all about equal in size and arranged in 2 horizontal rows. The common, house-dwelling yellow sac spider, Cheiracanthium mildei, is a small spider that spins a silken sac web in the corners of ceilings and walls, and behind shelves and pictures it is also commonly found outdoors in shrubbery. Black widow bites are fairly common in California.įor more information about black widows, see Pest Notes: Widow Spiders and Their Relatives. Small children, the elderly, and persons with health problems are likely to suffer some of the more severe consequences of the bite. The internal effects may range from mild to severe. The symptoms of a black widow bite are largely internal little more than local redness and swelling may develop at the bite site. People are most likely to be bitten when they disturb the spider while they are cleaning out or picking up items in such places. They and their associated webs usually are found in dark, dry, sheltered, relatively undisturbed places. The egg sacs are mostly spherical, about 1/2 inch long and 1/2 inch in diameter, creamy yellow to light tan in color, opaque, and tough and paperlike on the surface.īlack widow spiders occur in most parts of California. The web of the black widow is an irregular, tough-stranded, sticky cobweb mesh in which the spider hangs with its underside up, showing the red hourglass. Contrary to popular belief, the female black widow rarely eats the male after mating but may do so if hungry. The male black widow does possess venom, but its fangs are too small to break human skin. The adult male black widow is one-half to two-thirds the length of the female, has a small abdomen, and is seldom noticed. Only the larger immature female and adult female spiders are able to bite through a person’s skin and inject enough venom to cause a painful reaction. In contrast, immature and male western black widows have white stripes on a tan abdomen and look very different from the adult females. The typical adult female black widow has a shiny black body, slender black legs, and a red or orange mark in the shape of an hourglass on the underside of the large, round abdomen. It is helpful if the offending spider can be caught and saved for identification by an arachnologist. Anyone bitten by this spider should remain calm and promptly seek medical advice. Venom from its bite can cause reactions ranging from mild to painful and serious, but death is very unlikely and many symptoms can be alleviated if medical treatment is obtained. The black widow spider, Latrodectus hesperus, is the most common harmful spider in California. However, only those spiders whose venom typically causes a serious reaction in humans are called “toxic” spiders. Most spiders have venom which they use to kill their prey. Common spider families are described in Table 1. Spiders have 8 legs and 2 body parts-a head region (cephalothorax) and an abdomen. Spiders resemble insects and sometimes are confused with them, but they are arachnids, not insects. The spiders commonly seen out in the open during the day are unlikely to bite people. Spiders that might injure people-for example, black widows-generally spend most of their time hidden outside homes in woodpiles or in clutter in the garage. Many people fear or dislike spiders but for the most part, spiders are beneficial because of their role as predators of insects and other arthropods, and most cannot harm people.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |