The red-imported fire ant was first documented in the US back during the 1930s, and since then this species has spread to numerous southern states where they are considered a major public health threat. Red-imported fire ants are the most common ant pest species in central Texas where their dirt mounds have become a dreaded sight to residents. These invasive ants are known for rapidly colonizing residential yards and inflicting stings that cause tremendous pain and result in unsightly pustule wounds. A relatively high number of people are allergic to red-imported fire ant venom, and for these sensitive individuals, a fire ant attack can lead to anaphylactic shock and even death if treatment is not sought out in a timely manner. During periods of drought and/or exceptionally hot weather, red-imported fire ants may invade homes where they are likely to seek out human food sources. Despite the notoriety of red-imported fire ants, colony workers can be difficult to identify for several reasons.
One of the most significant difficulties when it comes to accurately identifying red-imported fire ant workers has to do with the wide variation in their body sizes. Workers range in size from 1/16 of an inch in body length to 1/4 of an inch in body length, and the largest workers can be 3 times as large as the smallest workers. Red-imported fire ant workers are nearly identical to workers of the native tropical fire ant species, but close detection will reveal that tropical fire ants are composed of a minority of relatively large sized workers with square-shaped heads. Generally, native fire ant workers are more uniform in size than red-imported fire workers, but unlike other mound-building ants, like harvester ants and leafcutter ants, both native and red-imported fire ants create dirt mounds with no central entry/exit hole. However, red-imported fire ant mounds are typically a bit larger in both height and circumference. When finding dirt mounds with no central entrance hole, residents should assume that the mounds belong to red-imported fire ants due to the species commonality in central Texas.
Have you ever stepped on a red-imported fire ant mound?