Patch sampling behaviour and future foraging expectations in Argentine ants, Linepithema humile

Nests of Argentine ants, L. humile, were exposed to pairs of foraging patches of varying quality. These patches varied from never having food to having food for 4 h every day. After 15 days, colonies were allowed an added access to a new patch. The new patch, however, never contained food. The sampling behaviour of nests towards the initial patches and the new patch suggested that the nests were using a sampling rule based on maximizing net benefits of finding food minus the cost of sampling. The behaviour of the nests towards the new patch was also significantly affected by what the foraging workers had previouisly encountered in the foraging patches. The behaviour of the L. humile colonies is similar in pattern to what would result by Bayesian updating of expectations for success in novel foraging opportunities. These data are the first suggestions of such an ability in an insect. Copyright 1998 The Association for the Study of Animal Behaviour Copyright 1998 The Association for the Study of Animal Behaviour.