Trophallaxis in a communal halictine bee Lasioglossum (Chilalictus) erythrurum.

Food exchange by means of oral trophallaxis was confirmed for a communal halictine bee Lasioglossum (Chilalictus) erythrurum. These results demonstrate an independent evolution of trophallaxis in bees. The occurrence of trophallaxis in a communal species questions the role of trophallaxis in the evolution of sociality. Neutral arena encounters between one fed and one unfed female indicate that food exchange is not associated with familiarity. Donor females fed nestmates and nonnestmates in the same proportion, even when nonnestmates were from a separate nest aggregation located 7 km away. Such universal acceptance is expected if positive fitness benefits accrue from nearly all interactions with conspecifics in nature.