Anelosimus is a cosmopolitan genus of cobweb spiders (Theridiidae), currently containing 74 species. Anelosimus is a key group in the study of sociality and its evolution in spiders (Aviles 1997). It contains species spanning the spectrum from solitary to highly social (quasisocial), with eight quasisocial species, far more than any other spider genus. Among these is the South American social species Anelosimus eximius, among the best studied social spider species.
The web of a colony of A. eximius can reach cover entire tree canopies and contain tens of thousands of individuals. Most of the highly social species live in lowland tropical forests, and all occur in the Americas. Other species, particularly those at higher altitudes in northern latitudes in the Americas and all non-American species appear to be solitary or sub-social. Social Anelosimus species are generally highly inbred and have female-biased sex ratios, with up to 10 females per male.
The social, subsocial, and solitary behavior of differing species within Anelosimus has been used to examine hypotheses of environmental pressures on social behavior, and inbreeding. Subsociality as a trait seems to be conserved, despite the wide range of environments in which Anelosimus species live; all known solitary species within the genus belong to a single clade. Sociality, however, has independently arisen several times.
Description Anelosimus spiders have a notched red or brown band on their abdomen, which is dark when preserved in alcohol. Laterally, the abdomen has a white band and/or white blotches. Specimens range in size from . Individuals in this genus lack a colulus.
Species
, this genus includes 75 species:
Anelosimus agnar Agnarsson, 2006 – Malaysia Anelosimus amelie Agnarsson, 2009 – Comoros, Mayotte Anelosimus analyticus (Chamberlin, 1924) – United States, Mexico Anelosimus andasibe Agnarsson & Kuntner, 2005 – Madagascar Anelosimus arizona Agnarsson, 2006 – United States, Mexico Anelosimus ata Agnarsson, Kuntner & Jencik, 2015 – Madagascar Anelosimus baeza Agnarsson, 2006 – Mexico to Brazil Anelosimus bali Agnarsson, 2012 – Bali Anelosimus biglebowski Agnarsson, 2006 – Tanzania Anelosimus buffoni Agnarsson, Kuntner & Jencik, 2015 – Madagascar Anelosimus chickeringi Levi, 1956 – Mexico to Peru Anelosimus chonganicus Zhu, 1998 – China Anelosimus crassipes (Bösenberg & Strand, 1906) – China, Korea, Japan Anelosimus darwini Agnarsson, Kuntner & Jencik, 2015 – Madagascar Anelosimus decaryi (Fage, 1930) – Seychelles (Aldabra), Madagascar, Comoros, Mayotte Anelosimus dialeucon (Simon, 1890) – Yemen Anelosimus dianiphus (Rainbow, 1916) – Australia (Queensland) Anelosimus domingo Levi, 1963 – Colombia to Suriname and Peru Anelosimus dubiosus (Keyserling, 1891) – Brazil Anelosimus dubius (Tullgren, 1910) – Tanzania Anelosimus dude Agnarsson, 2006 – Tanzania Anelosimus eidur Agnarsson, 2012 – New Guinea Anelosimus elegans Agnarsson, 2006 – Mexico to Peru Anelosimus ethicus (Keyserling, 1884) – Brazil Anelosimus exiguus Yoshida, 1986 – China, Japan, Ryukyu Is. Anelosimus eximius (Keyserling, 1884) – Lesser Antilles, Panama to Argentina (type species) Anelosimus fraternus Bryant, 1948 – Hispaniola Anelosimus guacamayos Agnarsson, 2006 – Ecuador Anelosimus hookeri Agnarsson, Kuntner & Jencik, 2015 – Madagascar Anelosimus huxleyi Agnarsson, Veve & Kuntner, 2015 – Madagascar Anelosimus inhandava Agnarsson, 2005 – Brazil, Argentina Anelosimus iwawakiensis Yoshida, 1986 – Korea, Japan Anelosimus jabaquara Levi, 1956 – Brazil Anelosimus jucundus (O. Pickard-Cambridge, 1896) – Mexico to Argentina Anelosimus kohi Yoshida, 1993 – Malaysia, Singapore Anelosimus lamarcki Agnarsson & Goh, 2015 – Madagascar Anelosimus linda Agnarsson, 2006 – Malaysia Anelosimus lorenzo Fowler & Levi, 1979 – Brazil, Paraguay, Uruguay, Argentina Anelosimus luckyi Agnarsson, 2012 – New Guinea Anelosimus may Agnarsson, 2005 – Madagascar Anelosimus membranaceus Zhang, Liu & Zhang, 2011 – China (Hainan) Anelosimus misiones Agnarsson, 2005 – Argentina Anelosimus monskenyensis Agnarsson, 2006 – Kenya Anelosimus moramora Agnarsson, Kuntner & Jencik, 2015 – Madagascar Anelosimus nazariani Agnarsson & Kuntner, 2005 – Madagascar Anelosimus nelsoni Agnarsson, 2006 – South Africa Anelosimus nigrescens (Keyserling, 1884) – Guyana, Brazil Anelosimus octavius Agnarsson, 2006 – Mexico to Costa Rica Anelosimus oritoyacu Agnarsson, 2006 – Mexico to Ecuador Anelosimus pacificus Levi, 1956 – Mexico to Costa Rica, Jamaica Anelosimus pantanal Agnarsson, 2006 – Brazil Anelosimus placens (Blackwall, 1877) – Seychelles Anelosimus pomio Agnarsson, 2012 – Papua New Guinea (New Britain) Anelosimus potmosbi Agnarsson, 2012 – New Guinea Anelosimus pratchetti Agnarsson, 2012 – Australia (New South Wales) Anelosimus pulchellus (Walckenaer, 1802) – Europe, Caucasus, Iran, North Africa Anelosimus puravida Agnarsson, 2006 – Guatemala to Panama Anelosimus rabus Levi, 1963 – Brazil Anelosimus rupununi Levi, 1956 – Trinidad to Brazil Anelosimus sallee Agnarsson & Kuntner, 2005 – Madagascar Anelosimus salut Agnarsson & Kuntner, 2005 – Madagascar Anelosimus seximaculatus (Zhu, 1998) – China (Hainan) Anelosimus studiosus (Hentz, 1850) – USA to Argentina Anelosimus subcrassipes Zhang, Liu & Zhang, 2011 – China (Hainan) Anelosimus sulawesi Agnarsson, 2006 – Indonesia (Sulawesi) Anelosimus sumisolena Agnarsson, 2005 – Brazil Anelosimus taiwanicus Yoshida, 1986 – Taiwan, Indonesia (Krakatau) Anelosimus terraincognita Agnarsson, 2012 – possibly Australasia Anelosimus tita Agnarsson, Kuntner & Jencik, 2015 – Madagascar Anelosimus torfi Agnarsson, 2015 – Madagascar Anelosimus tosus (Chamberlin, 1916) – Mexico to Peru Anelosimus vierae Agnarsson, 2012 – Uruguay, Argentina Anelosimus vittatus (C. L. Koch, 1836) – Europe, Turkey, Caucasus, Iran Anelosimus vondrona Agnarsson & Kuntner, 2005 – Madagascar Anelosimus wallacei Agnarsson, Veve & Kuntner, 2015 – Madagascar
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