The diffuse, highly fluid colony structure of Argentine ants allows the exchange of ants and resources among nests. We studied the movement of ant food resources in Californian vineyards by allowing ants to feed on protein-labelled sugar water for six days, then collecting ants at various distances from the sugar source and testing them for the presence of the protein. The percentage of ants marked with the protein decreased as distance from the sugar source increased, but the labelled food moved across distances much greater than average inter-nest distances, reflecting the diffuse structure of Argentine ant colonies.