Theridiidae - Cobweb spiders
From left to right: Achaearanea sp. gumfoot web, Anelosimus baeza palp, the social Theridion nigroannulatum, Selkirkiella sp., Theridion sp.
Theridiidae, or cobweb spiders, is a diverse family of spiders, Also known as the tangle-web spiders and comb-footed spiders, the family as of 2011 contains some 2300++ species in over 100 genera. In many tropical surveys the vast majority of theridiids caught are undescribed (pers. obs.) hinting that actual diversity is much higher, easily over 10.000 species. Many theridiids spin three-dimensional webs, often incorporating sticky lines attached to the substrate, or gumfoot threads (Agnarsson 2004). However, web architectural diversity is very high including a variety of cobwebs and sheets, to simplified H-shaped and single line webs, and many theridiids have abandoned web-building altogether and are wanderers. Theridiids are found throughout the world, but are most diverse in the tropics, and in many tropical habitats rank among the top 1-2 most diverse spider families.
The family includes some model research organisms such as the medically important widow spiders (Latrodectus), the genus Anelosimus, model organisms in the study of sociality, as well as the Hawaiian "happyface" spider (Theridion grallator), a well studied example of color polymorphism and the genetics underlying such polymorphism. The family also contains the kleptoparasites Argyrodes and Faiditus that live in large webs of other spiders and steal small prey caught by their host's web, eat prey killed by the host spider, and may consume silk from the host web, as well as attack and eat the host itself. Remarkably Argyrodine kleptoparasites can make up as much as 10% of the colony members of social Anelosimus colonies.
The family includes some model research organisms such as the medically important widow spiders (Latrodectus), the genus Anelosimus, model organisms in the study of sociality, as well as the Hawaiian "happyface" spider (Theridion grallator), a well studied example of color polymorphism and the genetics underlying such polymorphism. The family also contains the kleptoparasites Argyrodes and Faiditus that live in large webs of other spiders and steal small prey caught by their host's web, eat prey killed by the host spider, and may consume silk from the host web, as well as attack and eat the host itself. Remarkably Argyrodine kleptoparasites can make up as much as 10% of the colony members of social Anelosimus colonies.
Theridiidae models, from left to right: Latrodectus hesperus, Anelosimus kohi, Theridion grallator, Faiditus sp.
Theridiidae systematics is challenging.
Unfortunately, much of the current taxonomic effort on the family,
though valuable in speeding discovery of species, seems to ingore, or
omit, phylogenetic evidence. Hence, the family contains a large number
of genera whose monophyly is untested, as well as a remarkable number of
monotypic genera, whose placement in the theridiid tree of life is
unknown.
Our work aims to provide a phylogenetic backbone for Theridiidae for comparative analyses, and to establish a natural classification system for the family.
Our work aims to provide a phylogenetic backbone for Theridiidae for comparative analyses, and to establish a natural classification system for the family.
