[Aim] Ageratina adenophora is a serious invasive weed in China. Adaptation of the specific natural enemy, the tephritid fly Procecidochares utilis to native vs. invasive host plant populations is one of the important points in exploring the invasive mechanisms for this plant.[Method] In this study, we determined the selectivity of P. utilis between native and invasive populations of A. adenophora, and the ovarian protein content and acetylcholinesterase, carboxylesterase, glutathione S-transferase activities of P. utilis reared on native vs.invasive populations of A. adenophora.[Result] There was no significant difference in host selection by P. utilis between the two kinds of host population. The ovarian protein content of P. utilis reared on invasive populations of A. adenophora was higher than when reared on natives. The carboxylesterase activities of P. utilis reared on invasive host plants was lower than on native ones, but the glutathione S-transferase activity was higher in females. There was no significant difference in comparisons of the acetylcholinesterase activity.[Conclusion] The adaptation of A. adenophora to the specific natural enemy P. utilis decreased to some extent, which confirms the natural Enemy Escape Hypothesis for the invasion mechanism of invasive plants.