have disruptive coloration, stripes and blotches that break up their outlines. In a few species, such as the Hawaiian happy-face spider, Theridion grallator, several coloration schemes are present in a ratio that appears to remain constant, and this may make it more difficult for predators to recognize the species. Most spiders are insufficiently dangerous or unpleasant-tasting for warning coloration to offer much benefit. However, a few species with powerful venom, large jaws or irritant bristles have patches of warning colors, and some actively display these colors when threatened. Many of the family Theraphosidae, which includes tarantulas and baboon spiders, have urticating hairs on their abdomens and use their legs to flick them at attackers. These bristles are fine setae (bristles) with fragile bases and a row of barbs on the tip. The barbs cause intense irritation but there is no evidence that they carry any kind of venom. A few defend themselves against wasps by including networks of very robust threads in their webs, giving the spider time to flee while the wasps are struggling with the obstacles. The golden wheeling spider, Carparachne aureoflava, of the Namibian desert escapes parasitic wasps by flipping onto its side and cartwheeling down sand dunes. Socialization A few spider species that build webs live together in large colonies and show social behavior, although not as complex as in social insects. Anelosimus eximius (in the family Theridiidae) can form colonies of up to 50,000 individuals. The genus Anelosimus has a strong tendency towards sociality: all known American species are social, and species in Madagascar are at least somewhat social. Members of other species in the same family but several different genera have independently developed social behavior. For example, although Theridion nigroannulatum belongs to a genus with no other social species, T. nigroannulatum build colonies that may contain several thousand individuals that co-operate in prey capture and share food. Other communal spiders include several Philoponella species (family Uloboridae), Agelena consociata (family Agelenidae) and Mallos gregalis (family Dictynidae). Social predatory spiders need to defend their prey against kleptoparasites ("thieves"), and larger colonies are more successful in this. The herbivorous spider Bagheera kiplingi lives in small colonies which help to protect eggs and spiderlings. Even widow spiders (genus Latrodectus), which are notoriously cannibalistic, have formed small colonies in captivity, sharing webs and feeding together. In experiments, spider species like Steatoda grossa, Latrodectus hesperus and Eratigena agrestis stayed away