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Ariadna

Ariadna is a genus of tube-dwelling spider (family Segestriidae).

Distribution

Ariadna are found on all continents except Antarctica. About a third of the species are endemic to Australia. Fifteen described species are endemic to South Africa. Less than ten species are found in Europe and North America, respectively.

Behavior

Spiders in this genus are nocturnal.

Prey capture

The spiders are seen in the entrance of the tubes during the night with the tip of 6 legs visible on the rim of the tube. Prey movement is transmitted with vibrations to the spider from the radiating trip lines. The surprisingly swift reaction with which the spider strikes could be compared with that of a jack-in-the-box. The prey is seized and pulled instantly back into the tube. The double row of strong spines on the ventral surface of the front legs helps to grab and hold the prey. The third pair of legs directed forwards with legs I and II, help with the quick forward and backward movement of the spider in the tube. The entrance of the Ariadna tube has a small collar of very regular white silk.The trip lines have no adhesive elements and have only a signalling function.

Description

The genus Ariadna comprises tube-web spiders with a body size ranging from 6-15 mm, with males similar in size to females. Body color varies from yellowish brown to reddish black to purplish black abdomens without patterns, or if patterns are present they consist of transverse bars. The carapace is longer than wide with the fovea appearing as a small depression and ranges from hirsute to glabrous.

The species of this genus have six eyes arranged in two rows, all pale in colour and positioned close to the clypeal edge. Chelicerae are free, long and slender with small fangs and a cheliceral furrow with few teeth. Endites are longer than wide and well developed. The labium is much longer than wide with a well-developed serrula arranged in a single row.

The abdomen is longer than wide, cylindrical and hairy with short spinnerets and contiguous anterior spinnerets. Legs are three-clawed with the third pair of legs directed forwards along with legs I and II. Front legs have a double row of spines ventrally. The genitalia are haplogyne.

Taxonomy

The genus Ariadna was established by Audouin in 1826, with Ariadna insidiatrix <small>Audouin, 1826</small> as the type species.

Species

, this genus includes 147 species.

These species have articles on Wikipedia:

References