The little fire ant, Wasmannia auropunctata, was discovered on the Galapagos Islands by R. Silberglied, but according to Clark et al. its arrival in the archipelago probably predates that time. On colonized Galapagos Islands, as well as other invaded areas around the world, control of this pest ant species was based on "classical" methods such as the use of highly poisonous and persistent chemicals. Numerous ecological and behavioral studies have demonstrated the impact of W. auropunctata on native and endemic invertebrate fauna of the Galapagos Islands. The chapter presents the results of a field test using methoprene against W. auropunctata on Santa Cruz Island. In Bellavista, W. auropunctata occupied 81% of all the baits. For the rest, a number of beetles and cockroaches were seen, but constituted less than 10% of the total.