Fig. 3

Activity levels of insecticide metabolizing enzymes. a Glutathione S-transferase. b Esterase. c Quantities of monooxygenases. d Residual acetylcholinesterase activity in P. argentipes originated from the study sites Mirigama, Thalawa, Pannala and Mamadala. The discriminating values for each measure as used for anopheline mosquitoes [39, 64] are shown as interrupted lines (a–d). In the case of cytochrome P450, the discriminating value of anopheline mosquitoes is at 0.35 equivalent units, therefore, is off the scale and not shown (c). Shaded boxes indicate the percentage of flies in each activity range of assays with the short horizontal line in each shaded box representing the mean value. The vertical lines that extend from each shaded box represent the percentage of flies that deviated from the mean activity levels at each study site