Synonyms and other taxonomic changes
Subgenus (Solenopsis), not currently recognized as a valid taxon
Explanation of Names
Fire ants are named for their painful stings.
Size
Workers 2.5-4.5mm -- Mature colonies contain all or most of this size range.
Identification
Like all Solenopsis, these have ten-segmented antennae with a two-segmented club. Fire ants are recognized by their relatively large size (>2.5mm), polymorphic worker caste, and flagellar segments longer than broad. They are also noteworthy for their painful stings.
Other species groups in this genus are tiny (<2 mm), with monomorphic workers, and with short flagellomeres that appear disc-like.
Range
Warm-temperate and subtropical USA (the "Sunbelt" states), and southward.
Habitat
Disturbed, open areas, such as pastures, edges of crop fields, lawns, gardens, floodplains, frequently burned grasslands and pinelands. Nest are in soil, and in cooler or wetter weather, often with a conspicuous tumulus or mound.
Remarks
Sometimes called subgenus (Solenopsis), but the monophyly of this group is uncertain, as is that of all Solenopsis subgenera. Hence, none of the latter are currently recognized as valid, but anyone familiar with these ants can easily recognize fire ants from others in the genus.