Comparative analysis on esterase activity in Solenopsis invicta and Solenopsis richteri (Hymenoptera: Formicidae)

Solenopsis invicta and Solenopsis richteri are two very closely related invasive ant species.  Despite being very similar in biology and behavior, S. invicta is an invader with much more success.  Toxic tolerance has been found to be important to the success of some invasive species.  Esterases play an important role in insect detoxification process.  In this study, we tested the hypothesis that S. invicta has higher esterase activity than S. richteri.  The results strongly supported our hypothesis.  For both substrates, α-naphthyl acetate (α -NA) and β-naphthyl acetate (β -NA), S. invicta workers showed significantly higher mean level of esterase activity than S. richteri.  The higher esterase activities may contribute to the higher toxic tolerance in S. invicta and thus their invasive success.