Theridiidae, also known as the tangle-web spiders, cobweb spiders and comb-footed spiders, is a large family of araneomorphspiders first described by Carl Jakob Sundevall in 1833.[1] This diverse, globally distributed family includes over 3,000 species in 124 genera,[2] and is the most common arthropod found in human dwellings throughout the world.[3]
Theridiid spiders are both entelegyne,[4] meaning that the females have a genital plate, and ecribellate, meaning that they spin sticky capture silk instead of woolly silk. They have a comb of serrated bristles (setae) on the tarsus of the fourth leg.
The family includes some model organisms for research, including the medically importantwidow spiders. They are important to studies characterizing their venom and its clinical manifestation, but widow spiders are also used in research on spider silk and sexual biology, including sexual cannibalism. Anelosimus are also model organisms, used for the study of sociality, because it has evolved frequently within the genus, allowing comparative studies across species, and because it contains species varying from solitary to permanently social.[5] These spiders are also a promising model for the study of inbreeding because all permanently social species are highly inbred.[6]
The HawaiianTheridion grallator is used as a model to understand the selective forces and the genetic basis of color polymorphism within species. T. grallator is known as the "happyface" spider, as certain morphs have a pattern resembling a smiley face or a grinning clown face on their yellow body.[7][8]
They often build tangle space webs, hence the common name, but Theridiidae has a large diversity of spider web forms.[9] Many trap ants and other ground dwelling insects using elastic, sticky silk trap lines leading to the soil surface. Webs remain in place for extended periods and are expanded and repaired, but no regular pattern of web replacement has been observed.[10]
The well studied kleptoparasitic members of Argyrodinae (Argyrodes, Faiditus, and Neospintharus) live in the webs of larger spiders and pilfer small prey caught by their host's web. They eat prey killed by the host spider, consume silk from the host web, and sometimes attack and eat the host itself.[11][12]
Theridiid gumfoot-webs consist of frame lines that anchor them to surroundings and of support threads, which possess viscid silk. These can either have a central retreat (Achaearanea-type) or a peripheral retreat (Latrodectus-type).[13][14] Building gum-foot lines is a unique, stereotyped behaviour, and is likely homologous for Theridiidae and its sister family Nesticidae.[15]
Among webs without gumfooted lines, some contain viscid silk (Theridion-type) and some that are sheet-like, which do not contain viscid silk (Coleosoma-type). However, there are many undescribed web forms.
^Benjamin, Suresh P.; Zschokke, Samuel (2002). "Untangling the tangle-web: web building behaviour of the comb-footed spider Steatoda triangulosa and comments on phylogenetic implications (Araneae: Theridiidae)". Journal of Insect Behavior. 15 (6): 791–809. doi:10.1023/A:1021175507377. S2CID26850827.
^Vollrath, F. (1979). "Behavior of the Kleptoparasitic Spider Argyrodes-Elevatus (Araneae, Theridiidae)". Animal Behaviour. 27: 515–521. doi:10.1016/0003-3472(79)90186-6. S2CID53177663.
^Blackledge, T.A.; Zevenbergen, J.M. (2007). "Condition dependent spider web architecture in the western black widow Latrodectus hesperus". Animal Behaviour. 73 (5): 855–864. doi:10.1016/j.anbehav.2006.10.014. S2CID53182880.
Agnarsson I. 2006c. Phylogenetic placement of Echinotheridion (Araneae: Theridiidae) - do male sexual organ removal, emasculation, and sexual cannibalism in Echinotheridion and Tidarren represent evolutionary replicas? Invertebrate Systematics 20: 415–429. PDFArchived 2007-09-27 at the Wayback Machine
Agnarsson I. 2004. Morphological phylogeny of cobweb spiders and their relatives (Araneae, Araneoidea, Theridiidae). Zoological Journal of the Linnean Society 141: 447–626. PDFArchived 2007-01-01 at the Wayback Machine
Arnedo, M.A., Coddington, J., Agnarsson, I. & Gillespie, R.G. (2004). From a comb to a tree: phylogenetic relationships of the comb-footed spiders (Araneae, Theridiidae) inferred from nuclear and mitochondrial genes. Molecular Phylogenetics and Evolution 31:225-245. PDF
Arnedo MA, Agnarsson I, Gillespie RG. In Press. Molecular insights into the phylogenetic structure of the spider genus Theridion (Araneae, Theridiidae) and the origin of the Hawaiian Theridion-like fauna. Zoologica Scripta.
Aviles, L., Maddison, W.P. and Agnarsson, I. 2006. A new independently derived social spider with explosive colony proliferation and a female size dimorphism. Biotropica, 38: 743–753.
Gillespie, R.G. and Tabashnik, B.E. 1994. Foraging Behavior of the Hawaiian Happy Face Spider (Araneae, Theridiidae). Annals of the Entomological Society of America, 87: 815–822.
Oxford, G.S. and Gillespie, R.G. 1996. Genetics of a colour polymorphism in Theridion grallator (Araneae: Theridiidae), the Hawaiian happy-face spider, from greater Maui. Heredity, 76: 238–248.
