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Uloborus

Uloborus is a spider genus in the family Uloboridae with 79 described species.

Distribution

Most species occur in the tropics and subtropics, with only a few species in northern America and Europe.

Life style

Uloborus spiders build small orb-webs with cribellate silk. The hub is often meshed or strengthened with a stabilimentum that varies in shape, with the most common configuration being a linear silk band.

The web is usually tugged forcefully as the spider approaches the prey to locate it and entangle it further. The first, and to a lesser extent the second legs, are used for tugging. The front legs are used to lightly touch the prey. Hanging from the first and second legs, the spider uses the fourth pair of legs to throw silk onto the prey to subdue it. The spider faces away from the prey while wrapping it. The silk entangles the thrashing limbs, preventing injury to the spider. They prey on a variety of flying insects.

Uloborids lack venom glands and use digestive enzymes that are poured onto the prey to kill them. The silk wrapped around the prey becomes transparent after absorbing some of the enzymes. Spiders are frequently seen with large prey masses in their mouths.

Description

The chelicerae of these cribellate spiders are robust, but, like all Uloboridae, there are no venom glands. Eight small eyes are present.

The carapace is pear-shaped. The cephalic and thoracic regions of females are level, with the thoracic depression being a shallow pit. The cephalic region of males is curved slightly downward from the thoracic depression. The eight eyes are arranged in two rows and both eye rows are recurved.

The abdomen is longer than wide with 1-2 humps. The colour of the body is usually dull shades of cream, grey or brown, usually with markings.

Legs I and IV are longer than the other legs. The tibiae I have a brush of long setae in some species.

Species

, this genus includes 72 species and five subspecies:

References