Tangle+Web+Spiders+(Theridiidae)

__Taxonomy__ Kingdom: Animalia Phylum: Arthropoda Class: Arachnida Order: Araneae Family: Theridiidae



__Introduction__ Tangle web spiders, also known as cobweb spiders or comb-footed spiders, are a very diverse family of spiders. There are over 2,300 known species in over 100 genera. Interesting characteristics of this group include a genital plate (entelegyne) in females and sticky capture silk (araneomorph ecribellate) instead of wooly silk. These spiders often build three dimensional tangle space webs, and have setae, or serrated bristles, on the tarsus of the fourth leg. The setae are useful in helping the spider wrap its silk around the captured prey (Benjamin & Zschokke, 2003).

__Theridiidae Studies__ Theridiidae spiders have been used in a wide range of research studies: 1. **Medical use**- The genus //Latrodectus// (widow spiders) are important in medical research because of their venom and its potential applications in the clinical setting (Grasso, 1976). 2. **Study of sociality**- The genus //Anelosimus// within the family Theridiidae contains spiders that are solitary, subsocial, parasocial and eusocial. Since sociality has developed independently many times within this genus, this allows for comparative studies across species and the study of the ecological and evolutionary causes and consequences of sociality. 3. **Study of sexual cannibalism**- Sexual cannibalism is common in the genus //Latrodectus// (hence the nickname "black widow spider"). Female widow spiders have venom that is three times stronger than the venom of the male widow spiders. This is thought to have evolved to increase the odds of survival of the offspring (Knoflach & van Harten, 2001). 4. **Spider silk**- Widow spiders have been found to have silk with tensile strength similar to that of many orb-weaving spiders (Levi, 1959). 5. **Color polymorphism**- Theridiidae are used to understand the genetics behind color polymorphism (Reillo, 1989). There is a species of spider (//Theridion grallator,// or the happyface spider) in which certain morphs have a pattern that looks like a smiling face. 6. **Kleptoparasitism**- in spiders, this is a form of feeding where one spider will steal/feed on prey captured by other spiders (Agnarsson, 2002). This occurs in only five families of spiders, Theridiidae being one of these.

__Websites to visit__ [|The Agnarsson Lab]

__References__ Agnarsson, I. (2002). Sharing a web—on the relation of sociality and kleptoparasitism in theridiid spiders (theridiidae, araneae). //The Journal of Arachnology//, //30//, 181-188. Retrieved from http://www.gwu.edu/~spiders/content/publications/Agnarsson 2002.pdf

Benjamin, S. P., & Zschokke, S. (2003). Webs of theridiid spiders: Construction, structure and evolution. //Biological Journal of the Linnean Society//, //78//(3), 293-305. Retrieved from http://onlinelibrary.wiley.com/doi/10.1046/j.1095-8312.2003.00110.x/abstract;jsessionid=FDE499FB0F10F94614C3A0C415E5642B.f03t01?deniedAccessCustomisedMessage=&userIsAuthenticated=false

Grasso, A. (1976). Preparation and properties of a neurotoxin purified from the venom of black widow spider (latrodectus mactans tredecimguttatus). //Biochimica et Biophysica Acta//,//439//(2), 406-412. Retrieved from http://www.sciencedirect.com/science/article/pii/0005279576900775

Knoflach, B., & van Harten, A. (2001). Tidarren argo sp. nov. (araneae: Theridiidae) and its exceptional copulatory behaviour. //Journal of Zoology//, //254//(4), 449-459. doi: 10.1017/S0952836901000954

Levi, H. (1959). The spider genus latrodectus (araneae, theridiidae). //Transactions of the American Microscopical Society//, //78//(1), 7-43. Retrieved from http://www.jstor.org/discover/10.2307/3223799?uid=3739952&uid=2&uid=4&uid=3739256&sid=21102907812253

Reillo, P. R. (1989). Color polymorphism in the spider enoplognatha ovata (araneae: Theridiidae).//American Midland Naturalist//, //122//(1), 199-203. Retrieved from http://www.jstor.org/stable/2425696

__Images__ Figure 1: //Tangle-web spider - family theridiidae// [Web]. (2012). Retrieved from http://www.youtube.com/watch?v=VCT_8pjV44Q

Figure 2: Wild, A. (Photographer). (2011, January 22). social_spiders1.jpg [Web Photo]. Retrieved from http://www.alexanderwild.com/keyword/theridiidae/i-gsz3rsT/A

Figure 3: Robinson, J. H. (Photographer). Black widow spider tiny male with female [Web Photo]. Retrieved from http://www.arkive.org/black-widow-spider/latrodectus-mactans/image-G68971.html

Figure 4: Murawski, D. (Photographer). Oh Stop it Happy Face Spider, You’re Making Me Blush! [Web Photo]. Retrieved from http://beforeitsnews.com/outdoors/2012/03/oh-stop-it-happy-face-spider-youre-making-me-blush-1852863.html

Created by K. Pinder