Spiders of the genus Argyrodes are kleptoparasites that steal prey from other web spiders. Recent studies have shown that in addition to stealing prey, they occasionally eat the silk of the host spider webs. How Argyrodes alters the two foraging tactics in the field is still unknown. The foraging behaviour of Argyrodes flavescens was observed in the south-western part of Japan where prey availability changes greatly with season. Silk-eating behaviour was commonly observed when insect prey availability on host webs was low, but when prey was abundant, only prey-stealing behaviour was observed. Spiders spent more time feeding on silk than on prey when prey was scarce. Moreover, in the season when most individuals fed on silk, only a small portion of individuals consumed prey. These results suggest that silk eating is an important alternative foraging tactic under seasonally changing environments.

Argyrodes flavipes illustrates a novel form of highly social behaviour in spiders. Although A. flavipes lives in groups, forages communally, and has parental care, it is also highly aggressive towards conspecifics. These observations, plus the relatively small group sizes, suggest that sociality in these animals may be more akin to that in social mammalian carnivores than in social insects. Most highly social spiders are thought to have developed sociality via the sub-social route because of their high level of parental care. Although A. flavipes also exhibits high levels of parental care, its phylogenetic background and the fact that it needs to defend its young from conspecifics, suggest that both sub-social and para-social factors may have influenced its social development.