Molecular and biochemical mechanisms of organophosphate resistance in laboratory-selected lines of the oriental fruit fly (Bactrocera dorsalis)

► Six different OP-resistant lines showed 13- to 814-fold increases in resistance (based on RRs). ► All of the resistant lines have the same three point mutations in the ace gene seen previously. ► All of the R lines (except the naled-r line) showed a similar pattern of esterase enzyme morphs. ► Differing effects on esterase activity were seen in relation to various OP compounds. ► Compared to the susceptible line, all of the resistant lines showed higher esterase Vmax values.