Araneae
(spiders)
Araneae: Taxonomy | Info | Species on this site
- Kingdom: Metazoa ((=Animalia) multicellular animals)
- Phylum: Arthropoda (arthropods)
- Class: Arachnida (spiders, harvestmen, scorpions, mites, etc.)
- Order: Araneae (spiders)
Spiders are quite common in Florida, and can be found anywhere where insects can be found. They range in size from the huge orb-weaving Nephila clavipes (golden silk orbweaver) and Argiope aurantia (yellow garden spider) to the tiny jumping spiders (Family: Salticidae). Some spin magnificant webs, waiting to catch their prey in mid-flight. Others, such as the wolf spiders (Family: Lycosidae) and jumping spiders, actively hunt their prey. Some spiders lie motionless on or in flowers waiting to ambush their prey that fly to them.
Basic spider anatomy
Spiders, especially the jumping spiders, are known to have exceptional eyesight brought by four (in some species, three, two, or one) pairs of simple eyes called ocelli. They're often arranged in varying ways that aid in determining the spider's species. Spiders have several appendages that are attached to the cephalothorax (fused head and thorax) and abdomen. The foremost are a single pair of chelicerae. These are used during feeding and defense; they contain the fangs and poison glands. The next set of appendages are a single pair of pedipalps that resemble very short legs; these are typically elongated in males and are used during mating. The next four pairs of appendages are the spider's legs, attached to the spider's cephalothorax. The legs of some spiders (especially the orb-weavers) have tiny hooks on the ends that are used for climbing across their webs and especially while guiding the silk from their spinnerets while spinning their webs. The last set of appendages range from one to four pairs of spinnerets that are usually attached at the end of the spider's abdomen. The spinnerets secrete the silk that spiders use for spinning webs, making or lining burrows, and making egg cases. Many spiders leave a trail of silk behind them, using it like a mountain-climber's safety rope.
Spider silk
Spider silk has been under study for quite some time because of its incredible tensile strength and elasticity. In fact, studies have shown that on an equal weight basis, spider silk is stronger than steel and Kevlar (material used in bullet-proof vests, etc.) DuPont, the manufacturer of Kevlar, wrote an interesting article in DuPont Magazine entitled, "Fiber Engineers, Meet Thy Master." It discusses the properties of orb-weaving spiders' dragline silk (the thick silk in an orb web that suspends the weight of the web, much like the long bowing cables of a suspension bridge) and how research is leading to synthetic silk of similar properties.
Here are several interesting off-site links about spider silk:
Venomous Spiders in Florida
There are presently two groups of venomous spiders established and/or occasionally found in isolated areas of Florida: the widow spiders (Genus: Latrodectus) and the recluse spiders (Genus: Loxosceles).
- Latrodectus bishopi - red widow
- Latrodectus geometricus - brown widow
- Latrodectus mactans - southern black widow
- Latrodectus variolus - northern black widow
- Loxosceles laeta - Chilean recluse
- Loxosceles reclusa - brown recluse
- Loxosceles rufescens - Mediterranean recluse
Extensive information on the above spiders can be found online through the Florida Department of Agriculture & Consumer Services - Division of Plant Industry:
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