The fire ants have rapidly become one of the most intensively studied groups of ants once some species ranked as top-rated global invasive pests.Such herein include the two invasive fire ant species occurring in China,namely Solenopsis invicta Buren and Solenopsis geminata F.Though even at their cradle localities fire ants are not a particularly diverse ant group(ca.20 described species),species determination within the genus Solenopsis is remarkably difficult.Smallest species and minor workers are often impossible to differentiate,largely due to recent speciation among sympatric lineages.