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:

Uloborus albescens O. Pickard-Cambridge, 1885 – Pakistan, India Uloborus albofasciatus Chrysanthus, 1967 – New Guinea Uloborus albolineatus Mello-Leitão, 1941 – Argentina Uloborus ater Mello-Leitão, 1917 – Brazil Uloborus aureus Vinson, 1863 – Madagascar Uloborus barbipes L. Koch, 1872 – Australia (Queensland) Uloborus berlandi Roewer, 1951 – Guinea Uloborus biconicus Yin & Hu, 2012 – China Uloborus bigibbosus Simon, 1905 – India Uloborus bispiralis Opell, 1982 – New Guinea Uloborus campestratus Simon, 1893 – USA to Venezuela Uloborus canescens C. L. Koch, 1844 – Colombia Uloborus cellarius Yin & Yan, 2012 – China Uloborus chinmoyiae Biswas & Raychaudhuri, 2013 – Bangladesh Uloborus conus Opell, 1982 – New Guinea Uloborus crucifaciens Hingston, 1927 – Myanmar Uloborus cubicus (Thorell, 1898) – Myanmar Uloborus diversus Marx, 1898 – United States, Mexico Uloborus eberhardi Opell, 1981 – Costa Rica Uloborus elongatus Opell, 1982 – Argentina Uloborus emarginatus Kulczyński, 1908 – Indonesia (Java) Uloborus filidentatus Hingston, 1932 – Guyana Uloborus filifaciens Hingston, 1927 – India (Andaman Is.) Uloborus filinodatus Hingston, 1932 – Guyana Uloborus formosanus Yoshida, 2012 – Taiwan Uloborus formosus Marx, 1898 – Mexico Uloborus furunculus Simon, 1906 – India Uloborus gilvus (Blackwall, 1870) – Italy, Greece Uloborus glomosus (Walckenaer, 1841) – Canada, United States, Mexico Uloborus guangxiensis Zhu, Sha & Chen, 1989 – China Uloborus humeralis van Hasselt, 1882 – Myanmar, Indonesia (Sumatra, Java) U. h. marginatus Kulczyński, 1908 – Indonesia (Java) Uloborus inaequalis Kulczyński, 1908 – New Guinea Uloborus jabalpurensis Bhandari & Gajbe, 2001 – India Uloborus jarrei Berland & Millot, 1940 – Guinea Uloborus kerevatensis Opell, 1991 – Papua New Guinea Uloborus khasiensis Tikader, 1969 – India Uloborus krishnae Tikader, 1970 – India (mainland, Nicobar Is.) Uloborus leucosagma Thorell, 1895 – Myanmar Uloborus limbatus Thorell, 1895 – Myanmar Uloborus llastay Grismado, 2002 – Argentina Uloborus lugubris (Thorell, 1895) – Myanmar Uloborus metae Opell, 1981 – Colombia Uloborus minutus Mello-Leitão, 1915 – Brazil Uloborus modestus Thorell, 1891 – India (Nicobar Is.) Uloborus montifer Marples, 1955 – Samoa Uloborus niger Mello-Leitão, 1917 – Brazil Uloborus oculatus Kulczyński, 1908 – Singapore Uloborus parvulus Schmidt, 1976 – Canary Islands Uloborus penicillatoides Xie, Peng, Zhang, Gong & Kim, 1997 – China Uloborus pictus Thorell, 1898 – Myanmar Uloborus pinnipes Thorell, 1877 – Indonesia (Sulawesi) Uloborus planipedius Simon, 1897 – South Africa Uloborus plumipes Lucas, 1846 – Europe, Africa, Yemen, Iran, Pakistan. Introduced to Argentina, Philippines, Japan U. p. javanus Kulczyński, 1908 – Indonesia (Java) Uloborus pteropus (Thorell, 1887) – Myanmar Uloborus rufus Schmidt & Krause, 1995 – Cape Verde Uloborus scutifaciens Hingston, 1927 – Myanmar Uloborus segregatus Gertsch, 1936 – USA to Colombia, Galapagos Uloborus sexfasciatus Simon, 1893 – Philippines Uloborus shendurneyensis Asima, Sudhikumar & Prasad, 2021 – India Uloborus spelaeus Bristowe, 1952 – Malaysia Uloborus strandi (Caporiacco, 1940) – Ethiopia Uloborus tenuissimus L. Koch, 1872 – Samoa Uloborus tetramaculatus Mello-Leitão, 1940 – Brazil Uloborus trifasciatus Thorell, 1890 – Indonesia (Sunda Is.) Uloborus trilineatus Keyserling, 1883 – Mexico to Argentina Uloborus umboniger Kulczyński, 1908 – Sri Lanka Uloborus undulatus Thorell, 1878 – Indonesia, (Java) U. u. indicus Kulczyński, 1908 – Malaysia U. u. obscurior Kulczyński, 1908 – New Guinea U. u. pallidior Kulczyński, 1908 – Indonesia, (Java) Uloborus vanillarum Vinson, 1863 – Madagascar Uloborus velutinus Butler, 1883 – Madagascar Uloborus villosus Keyserling, 1881 – Colombia Uloborus viridimicans Simon, 1893 – Philippines Uloborus walckenaerius Latreille, 1806 – Madeira, Europe, Turkey, Caucasus, Russia (Europe to Far East), Iraq, Iran, Kazakhstan, Central Asia, China, Korea, Japan. Introduced to Cape Verde, St. Helena, South Africa (type species)

References