Zoology Quick Snippet: Common House Spiders

Discussion in 'Zoology' started by mscbkc070904, Feb 11, 2005.

  1. mscbkc070904

    mscbkc070904 Premium Member

    Although this is alot to read, but it best to educate people of what they have possibly around their home and be able to identify in the event a child or adult is bitten and may result from sickness. I will provide the introduction and please do go to the link to see more about each spider and a pic of the spider so you have a visual of what it looks like.

    Class: Arachnida
    Order: Araneae
    Common Name Family
    Cobweb Spiders Theridiidae
    Orb Weaver Spiders Araneidae
    Funnel Web Spiders Agelenidae
    Cellar Spiders Pholcidae
    Wolf Spiders Lycosidae
    Jumping Spiders Salticidae
    Nursery Web Spiders Pisauridae
    Crab Spiders Thomisidae

    Many people are afraid of spiders. This fear is partly due to myths and to the notoriety of harmful species such as the brown recluse spider (see HYG-2061) and the black widow spider (see HYG-2061A). Several species of sac spiders (clubionids) are suspected of being responsible for most spider bites, especially ones occurring indoors (see HYG-2060A). Sac spider venom is cytotoxic, causing tissues at the bite site to die. However, the vast majority of spiders are harmless to humans.

    Although spiders are often unpopular, the venom of most species is not very toxic to humans, usually resulting in no more than a slight swelling, inflammation, or itching sensation. Most spiders’ fangs are too small or weak to puncture human skin. Spiders usually will not attempt to bite unless accidentally trapped against the skin or grasped, although some species actively guard their egg sacs or young.

    Spiders are beneficial predators that reduce pest populations (flies, crickets, mites, etc.) in and around homes, yards, gardens, and crops. Wholesale destruction of spiders should be avoided.

    For more information on spiders, particularly those that occur in Ohio, refer to http://www.marion.ohio-state.edu/spiderweb/ohiospiders.htm.

    Identification
    Spiders have eight legs (four pairs). They have two body regions: a cephalothorax (fused head and thorax) and an abdomen, which are joined together by a narrow waist. Most spiders have six or eight simple eyes in various arrangements. All have a pair of jaw-like structures, the chelicerae, each of which ends in a hollow fang through which venom can be ejected. The tip of the abdomen has a group of small fingerlike spinnerets that produce silk. Young spiders (spiderlings) resemble adults except for their smaller size and coloration.

    Life Cycle and Habits
    Spiders lay eggs within a silken egg sac that is often ball-shaped and either hidden in a web, affixed to a surface, or carried by the female. Spiders may produce several egg sacs, each containing up to several hundred eggs. A spider grows by shedding its skin (molting), usually four to twelve times before maturity. In many species, the mature male often wanders about in search of a mate. Some species of spiders may live for years, but most spiders only survive for one season.

    All spiders produce silk, which is secreted as a liquid through the spinnerets and hardens on air contact. Spiders use silk for a variety of purposes, such as making egg sacs, capturing prey, holding prey, making shelters or retreats, and transferring sperm during mating. Also, spiderlings extrude silk threads that enable them to be transported by air currents, a process called “ballooning.”

    Spiders are predators that typically feed on living prey. They produce venom that is poisonous to their normal prey of insects, mites, and other small arthropods. Venom is injected through the hollow fangs to immobilize the prey and begin the digestion process. Spiders can only ingest liquids, so they either inject or regurgitate digestive fluids into the prey. They then suck in the digested liquid food.

    Spiders use a variety of tactics to capture prey. Some species are web builders that use webbing to ensnare their prey. Others are active hunters that actively search for their prey. Passive hunters are spiders that lay in wait for their prey rather than searching for it.

    scroll down 1/3 of the page under the title: Spiders Commonly Associated with Structures
    http://ohioline.osu.edu/hyg-fact/2000/2060.html