nests. Impact The ants are ranked among the world's 100 worst invasive animal species. In its introduced range, the Argentine ant often displaces most or all native ants and can threaten native invertebrates and even small vertebrates that are not accustomed to defending against the aggressive ants. This can, in turn, imperil other species in the ecosystem, such as native plants that depend on native ants for seed dispersal, or lizards that depend on native ants or invertebrates for food. For example, the recent severe decline in coastal horned lizards in southern California is closely tied to Argentine ants displacing native ant species on which the lizards feed. Argentine ants sometimes tend aphid, mealybug, and scale insect colonies, sometimes relocating the parasites to unaffected plants, and their protection of these plant pests from predators and parasitoids can cause problems in agricultural areas. In return for this protection, the ants benefit by feeding off an excretion known as "honeydew". Thus, when Argentine ants invade an agricultural area, the population densities of these plant parasites can increase followed by an increase in damage to crops. There is also evidence that the presence of Argentine ant may decrease the number of pollinators that visit natural flowering plants via predation on the larvae of the pollinators. Pest control Argentine ants are a common household pest, often entering structures in search of food or water (particularly during dry or hot weather), or to escape flooded nests during periods of heavy rainfall. When they invade a kitchen, it is not uncommon to see two or three queens foraging along with the workers. Due to the large number of queens, eliminating a single queen does not stop the colony's ability to breed. Diatomaceous earth has been used to dust trails, feeding sites and nest entrances. Borate-sucrose water baits are toxic to Argentine ants, when the bait is 25% water, with 0.5–1.0% boric acid or borate salts. In spring, during a colony's growth phase, protein based baits may be more effective due to much higher demand from the egg-laying queens. Due to their nesting behavior and presence of numerous queens in each colony, it is generally impractical to spray Argentine ants with pesticides or to use boiling water as with mound building ants. Spraying with pesticides has occasionally stimulated increased egg-laying by the queens, compounding the problem. Pest control usually requires exploiting their omnivorous dietary habits, through use