Fire ants and aphids exhibit a mutualistic relationship whereby fire ants obtain honeydew, a carbohydrate rich excretion, from aphids and, in return, protect aphids from natural enemies and potential competitors. This behavior is called “tending” and results in larger aphid populations. In addition to larger aphid populations, fire ants may indirectly increase the production of alate aphids and increase aphid dispersal, thereby increasing the spread of aphid-vectored viruses. We investigated the effects of fire ants by manipulating densities of red imported fire ants in greenhouse and field experiments. We found that non-aphid herbivores and natural enemies were more abundant in tomato fields with suppressed densities of fire ants than in fields with high densities of fire ants. In contrast we found that aphids were more abundant in tomato fields with high fire ant densities. These results suggest that fire ants are consuming non-aphid herbivores and natural enemies while protecting honeydew-producing aphids. In a greenhouse study we found that aphids dispersed to neighboring plants significantly more frequently in the presence of fire ants than in no fire ant treatments. These results suggest that fire ants increase aphid dispersal, and may alter landscape ecology by connecting spatially disjunct plant populations via aphid dispersal, thereby increasing the spread of aphid-vectored viruses.