Fig. 6. Uptake of insecticide metabolites 3-phenoxybenzoic acid (PBA) and malathion monocarboxylic acid (MMA) in Malpighian tubule bundles, as detected by HPLC. Uptake in presence of inhibitor conditions (FL, 2 mmol l^–1; PBD, 10 mmol l^–1; or water pre-exposure) is plotted relative to control uptake (uptake with metabolite alone in Ringer's). N=4 samples for each. ^*Uptake of metabolite in presence of inhibitor condition significantly different from uptake in absence of inhibitor condition.