Primary resources may affect the structure of species assemblages in upper trophic levels of food webs. These bottom-up effects may involve important ecological processes that affect pest control. For example, population densities of natural enemies may increase when alternative preys are favored by a new resource. In this study, we tested the hypothesis that the addition of a primary resource in a banana agroecosystem will increase pest control of the banana weevil Cosmopolites sordidus by ants. The results show an increased predation of weevil eggs due to an increased abundance of ants. These results will be useful for the design of cropping systems that enhance the biological regulation of pests.