While most spiders have some amount of venom, Arizona is home to three species without any venom glands: the feather-legged spider, Philoponella arizonica, and Philoponella oweni. The most common nonvenomous spider in Arizona is the feather-legged spider, which receives its name from the tufts of hair on its front legs. Nonvenomous spiders kill their prey by wrapping them with spider silk; the dense amount of silk eventually crushes their prey. All three of Arizona's nonvenomous spiders are orb weaver spiders and belong to the Uloboridae family.
Arizona brown, brown recluse and black widow spiders are the three most frequently seen of Arizona's highly venomous spiders. All three of these spiders can penetrate human skin and have enough venom to cause serious damage. The Arizona brown spider and brown recluse are brown spiders which cause necrosis with their bites. Necrosis is the premature deadening of skin tissue. The skin of Arizona brown and brown recluse bite victims begins to blacken almost immediately after the incident. Black widow venom has neurotoxins and may cause damage to a human's nervous system. Other highly venomous spiders in Arizona include the brown widow, Apache recluse, and Tucson recluse.
Orb webs and cobwebs are the two primary webs spiders build in Arizona. Orb web spiders construct webs with a circular shape on the web's outer rings, while the web's middle has a unsymmetrical design. These webs are well-hidden, causing unsuspecting insects to fly into them. Some of Arizona's orb weaving spiders are the garden spider, spider orb weaver, spiny micrathena, corn spider and bolas spider. Cobwebs are three dimensional to distort an insect's perception of the web's structure. All cobweb spiders belong to the Theridiidae family and are also known as comb-footed spiders. Arizona's Theridiidae species are black widows, dewdrop spiders, false black widows and Rugathodes sexpunctatus -- a spider in the Latrodectus genus.
Spiders who do not build webs set traps for prey or use hunting techniques. Two of Arizona's largest spiders, tarantulas and wolf spiders, hide behind rocks and wait for their prey to pass by before pouncing. Instead of webs, both of these spiders build their nests in preexisting ground cavities. Another Arizona non-web spider, the jumping spider, jumps onto unsuspecting prey. Trap-door spiders wait for prey underneath a "trap door," or an object that's a mixture of earth and saliva. While the ogre-face spider has a web, it uses a silk net to catch prey. Other non-web spiders in Arizona are the green lynx and the spitting spider.