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Spider Definition & Meaning

An adult Araneus may have up to 1,000 such chemosensitive setae, most on the tarsi of the first pair of legs. Males have more chemosensitive bristles on their pedipalps than females. They have been shown to be responsive to sex pheromones produced by females, both contact and air-borne. The jumping spider Evarcha culicivora uses the scent of blood from mammals and other vertebrates, which is obtained by capturing blood-filled mosquitoes, to attract the opposite sex. Because they are able to tell the sexes apart, it is assumed the blood scent is mixed with pheromones. Spiders also have in the joints of their limbs slit sensillae that detect force and vibrations.

These ants are predators and the pheromones they release for communication have a notable deterrent effect on these spider species. Like most arthropods, spiders lack balance and acceleration sensors and rely on their eyes to tell them which way is up. Arthropods' proprioceptors, sensors that report the force exerted by muscles and the degree of bending in the body and joints, are well-understood. On the other hand, little is known about what other internal sensors spiders or other arthropods may have. The outer pair are "secondary eyes" and there are other pairs of secondary eyes on the sides and top of its head. Most spiders convert nitrogenous waste products into uric acid, which can be excreted as a dry material.

Many experiments have been conducted to study the effect of zero gravity on the design of spider webs. The smallest, Patu digua from Colombia, are less than 0.37 mm (0.015 in) in body length. The largest and heaviest spiders occur among tarantulas, which can have body lengths up to 90 mm (3.5 in) and leg spans up to 250 mm (9.8 in). The tiny male of the golden orb weaver is protected from the female by producing the right vibrations in the web, and may be too small to be worth eating. Add more cards to your Spider Solitaire foundation by selecting the card stack at the bottom right corner of the screen.

In addition to arthropods, some mygalomorphs are known to prey on frogs, small mammals, lizards, snakes, snails, and small birds. Araneomorphae account for the great majority of modern spiders, including those that weave the familiar orb-shaped webs. The Jurassic and Cretaceous periods provide a large number of fossil spiders, including representatives of many modern families.

Most of those with medically serious bites, such as recluse spiders and widow spiders , would rather flee and bite only when trapped, although this can easily arise by accident. The defensive tactics of Australian funnel-web spiders include fang display. Their venom, although they rarely inject much, has resulted in 13 attributed human deaths over 50 years. They have been deemed to be the world's most dangerous spiders on clinical and venom toxicity grounds, though this claim has also been attributed to the Brazilian wandering spider . Females of the water spider Argyroneta aquatica build underwater "diving bell" webs that they fill with air and use for digesting prey, molting, mating and raising offspring.

Spiders are further characterized by leglike pedipalps near the mouth, usually eight simple eyes, and book lungs or tracheae in the abdomen. Our goal is to create one of the best casual gaming platforms on the internet, and we can’t do it without your input. Whether you have an issue on our site, or have ideas for new games, let us know. There is no universal methodology for keeping score in Spider Solitaire.