Effect of hexaflumuron on intermediary metabolism of Ephestia kuehniella Zeller (Lepidoptera: Pyralidae)

The flour moth, Ephestia kuehniella, is one of the important pests of stored products that cause annually severe damages. In the current study, changes of detoxifying enzymes, some enzymes involved in intermediary metabolism and some non-enzymatic compounds were determined in the larvae of E. kuehniella treated with different concentrations of hexaflumuron. Larvae were treated by 100, 300 and 700 µg/ml of hexaflumuron and aceton (as control) at different time intervals of 24 and 48 hours. Larvae treated by 300 µg/ml of hexaflumuron demonstrated the highest activity of general esterases in both time intervals when α-naphtyl acetate was used as substrate. By using β-maphtyl acetate as substrate, the highest activity was observed in the larvae treated by 100 µg/ml of hexaflumuron. Similar results were observed in case of glutathione S-tranferase thatimply presence of some isoforms of these enzymes. After 24h, activity of alanine aminotransferase was elevated along with increase of hexaflumuron concentration but adverse results were observed after 48 h. In case of aspartate aminitranferase, the highest activity was observed in the larvae treated with 700 µg/ml concentration. Increasing of hexaflumuron concentration causes higher activity of lactate dehydrogenase in both time intervals. After 24h, the highest activity of phenoloxidase was observed in the larvae treated with 300 µg/ml but no statistical differences was observed after 48 hours. There were no significant differences for protein and triglyceride concentrations after 24 hours but their highest amounts were observed in the larvae treated with 300 µg/ml. Increasing of hexaflumuron concentration decreased amount of glycogen in the treated larvae. These results revealed that haxaflumuron could intervene in intermediary metabolism of E. kuehniella in addition to disruption in growth and development.