Abstract
Every tissue of a Spodoptera larva has more than two tissue specific AliEs separated by polyacrylamide gel electrophoresis. All AliEs were strongly inhibited by fenitroxon showing high affinity to this compound. Spodoptera larvae are rather tolerant to the mother compound, fenitrothion. To the contrary, most AliEs except for 3 of the midgut were not sensitive to TIA-230 which shows potent insecticidal activity to the larva. These results suggest the sequestration of fenitroxon by AliEs to be one of the degrading functions in the larva. AliE inhibited by fenitroxon restored 1/2 activity in 10 hr, and haemolymph AliE seemed to be newly synthesized through the larval development. From the result of experiments mixing haemolymph with fenitroxon solution at different ratios, capacity of the sequestration of haemolymph was estimated to be over 0.31 μg in a matured larva, a level comparable to LD-50 by injection of fenitroxon.
