Phintella piatensis is an unusual jumping spider because, despite being neither myrmecophagic nor myrmecomorphic, it associates with ants, including dangerous weaver ants. Although salticids typically spin cocoon-like nests for use as shelters, the nests of Phintella are unusually dense. These play an important role in how Phintella adapts to living with ants. In experiments, intraspecific interaction and mating increased the risk of being killed by ants when there was no accessible nest, while access to a nest eliminated this risk. Additionally, while outside nests, seeing ants made Phintella reluctant to mate, this being an unusual example of a small animal with exceptional eyesight compensating for predation risk when making vision-based mating decisions. On the whole, the behaviour of Phintella during intraspecific interaction had broad similarity to the pattern that is common in salticids, but with some of the details of courtship suggesting further adaptation to interacting in the presence of dangerous ants. © 2009 Taylor & Francis.