Triangulate cobweb spider

Order: AraneaeFamily: TheridiidaeGenus and also species: Steatoda triangulosa (Walckenaer)



This little household spider is easily overlooked together it weaves cobwebs in the dark corners the houses, basements, and also outbuildings. The human body is only about 1/8 to ¼ customs long. The cephalothorax is brownish orange. Every segment that the yellow foot is darker apically. The carefully pubescent abdomen is brown v a collection of white and yellow roughly triangular spots mid-dorsally and irregular markings laterally.

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This species is probably native to Eurasia and has been presented to north America relatively recently. That is known from central and southerly Europe, southern Russia, the Mediterranean, St. Helena, and the unified States. That is rarely in south America. In north America it is widespread and also abundant in your ar in and on houses. In both Europe and also North America it lives in dwellings in the northern component of its range and under stones and on walls of structures in the southern part of the range (Levi 1957, 1962). That is usual in towns and also cities, in and around synthetic structures, in dark corners that walls, reduced angles the windows, and under eaves (Archer 1946).

Like other comb-footed spiders (family Theridiidae), this spiders build irregular webs and also suspend themselves from this snares while wait for unsuspecting prey to approach. Utilizing a comb that serrated bristles on their hind foot they enswathe their food in difficult silk and wait for it come quiet before approaching close sufficient to bite. Steatoda triangulosa is a frequent associate that the brown recluse and also the typical house spider in closets and also crannies (Fitch 1963). It has been recognized to food on many kinds the smashville247.nets, including ants, spiders (including the brown recluse), ticks, and also pillbugs (Guarisco 1991). In Texas it has actually been well-known to prey on fire ants and also spiders inhabiting utility devices housings (Horner and Russell 1986; MacKay and also Vinson 1989).

Mating spiders and also egg sacs have been uncovered from late spring through early fall (Kaston 1981). Egg sacs, around the dimension of the adult spider, space made of loose woven white silk, and about 30 eggs room visible inside each sac.

Severe envenomation is uncommon complying with the bite of Steatoda species, and also there are no known cases of person envenomation through S. Triangulosa. Once Steatoda poisoning go occur, the neurotoxic symptom are comparable to those result from black widow bites. The related types Steatoda grossa, well-known as the false black widow or cabinet spider, has actually been blamed because that severe regional and local pain, nausea, and vomiting in Australia. The symptoms, comparable to those seen in latrodectism, have been treated successfully with Latrodectus antivenom (Graudins et al. 2002). In the joined States, S. Grossa is confined to the Gulf Coast and the West shore (Levi 1957). Fortunately, it shows up that this types does not happen in Arkansas. At least two species of Steatoda have also been implicated in human being envenomations in Europe (Cavalieri et al. 1987; Warrell et al. 1991).

Another related species, S. Borealis, is thought about one the the comb-footed spiders the most concern to city pest controllers, together with the black widow and also common residence spider (Snetsinger 1982). It is easily differentiated from S. Triangulosa by the dark colored abdomen with a narrow, irradiate colored mean line. Although it is the most typical Steatoda of the eastern joined States, it has actually never been uncovered in Arkansas and it is reportedly rare south of Illinois, Iowa, and Nebraska (Levi 1957).


Archer, A. F. 1946. The Theridiidae or comb-footed spiders that Alabama. Alabama Museum that Natural history Museum file 22: 67 pages.

Cavalieri, M., D. D’urso, A. Lassa, E. Pierdominici, M. Robello, and also A. Grasso. 1987. Characterization and some properties of the venom gland extract of a theridiid spider (Steatoda paykulliana) commonly mistaken for black widow spider (Latrodectus tredecimguttatus). Toxicon 25 (9): 965-974.

Comstock, J. H. 1940. The spider book. Doubleday, Doran and Company, Inc., brand-new York. 729 pages.

Fitch, H. S. 1963. Spiders of the college of Kansas Natural history Reservation and also Rockefeller experimental Tract. University of Kansas Museum of natural History, Lawrence. 202 pages.

Graudins, A., N. Gunja, K. W. Broady, and G. M. Nicholson. 2002. Clinical and in vitro evidence for the efficacy of Australian red-back spider (Latrodectus hasselti) antivenom in the therapy of envenomation by a cupboard spider (Steatoda grossa). Toxicon 40 (6): 767-775.

Guarisco, H. 1991. Predation of two common house spiders top top medically far-reaching pests. Transactions that the Kansas Academy of scientific research 94 (1-2): 79-81.

Horner, N. V., and D. Russell. 1986. Ummidia trapdoor spider recorded in a Steatoda internet (Araneae: Ctenizidae, Theridiidae). Newspaper of Arachnology 14: 142.

Kaston, B. J. 1981. Spiders of Connecticut. State Geological and Natural history Survey of Conecticut, department of eco-friendly Protection Bulletin 70: 1020 pages.

Levi, H. W. 1957. The spider genera Crustulina and also Steatoda in phibìc America, central America, and also the West Indies (Araneae, Theridiidae). Bulletin the the Museum of comparative Zoology 117 (3): 367-424.

Levi, H. W. 1962. The spider genera Steatoda and Enoplognatha in America (Araneae, Theridiidae). Psyche 69 (1): 11-36.

MacKay, P., and S. B. Vinson. 1989. Testimonial of the spider Steatoda triangulosa (Araneae: Theridiidae) as a predator the the red imported fire ant (Hymenoptera: Formicidae). Journal of the brand-new York Entomological culture 97 (2): 232-233.

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Warrell, D. A., J. Shaheen, P. D. Hillyard, and D. Jones. 1991. Neurotoxic envenoming by an immigrant spider (Steatoda nobilis) in southerly England. Toxicon 29 (10): 1263-1265.