Fire ants from Brazil now infest the southern United States. Unlike queen fire ants in Brazil, two queens in the United States share a nest. Ants from these nests are more aggressive than those from single-queen nests. By destroying virtually all insects in the nest area, these aggressive ants gain sole access to food sources, and the ant population skyrockets. Since certain predator insects in Brazil limit the fire-ant population there, importing such predator insects into the United States would be of overall benefit to the environment by stopping the increase of the fire-ant population in the United States. Each of the following is an assumption made in the argument EXCEPT: ['The predator insects from Brazil could survive in the ecological environment found in the United States.', 'The imported insects would not prove more damaging to the environment in the United States than are the fire ants themselves.', 'The rate of increase of the fire-ant population would not exceed the rate at which the predator insects could kill the ants.', 'The predator insects would stop the increase of the ant population before the ants spread to states that are farther north.']