a Percentage of available habitat occupied by fire ant colonies versus distance from the origin (bottom) of a range. Investment in parasitic queens increases and stabilizes the amount of habitat occupied by fire ant colonies b The percentage of all colonies that are headed by a parasitic queen versus distance from the origin of a range. Even small investments in parasitic queens lead to high proportions of parasitically founded colonies in the range interior. In all simulations, only claustrally founded colonies occur at the extreme range edge. Colors denote different levels of reproductive investment, lines show averages over all simulations for a given investment, and shading shows standard deviations.