Abstract: 【Aim】 This study attempted to test electroantennographic (EAG) and behavioral responses of the workers of the red imported fire ant (RIFA), Solenopsis invicta Buren, to its trail pheromones.【Methods】 Dufour’s gland of RIFA workers was dissected, and then extracted with hexane followed by GC-MS analysis. EAG and recruitment behavioral responses of the RIFA workers to Dufour’s gland extract, extract of workers, and synthesized farnesenes were tested. 【Results】 In comparison to farnesenes synthesized from (±)-nerolidol, the major component of Dufour’s gland extract was not Z, E-α-farnesene as previously identified. Dufour’s gland extract, extract of workers and different doses of synthesized farnesenes could elicit significant EAG responses in RIFA workers and there was no significant difference among Dufour’s gland extract, extract of workers and 100 μg farnesenes. Dufour’s gland extract and extract of workers elicited a significant recruitment behavior, but no recruitment response was elicited by synthesized farnesenes at various doses including 10, 1, 0.1 and 0.01 μg. 【Conclusion】 Z, E-α-farnesene is not the major component of tail pheromones of S. invicta. Dufour’s gland extract and extract of workers could elicit significant EAG and behavioral responses in RIFA workers.

Key words: Solenopsis invicta, Dufour’s gland, trail pheromone, electroantennogram (EAG), behavioral response