REGULATION OF FLIGHT CAPACITY AND CONTENTS OF ENERGY SUBSTANCES BY METHOPRENE IN THE MOTHS OF ORIENTAL ARMYWORM,MYTHIMNA SEPARATA*

Abstract The flight capacity and contents of energy substances in the moths of migratory Oriental armyworm, Mythimna separata (Walker)dosed with juvenile hormone analogue methoprene(JHM) were compared with the normal moth through day‐1 to day‐6 after the treatment. The flight capacity of JHM‐treated moths, as determined by a 12‐hours tethered‐flight test, was significantly lower than that of the controls, although it might differ with their age and sex. The moth's flight capacity between the treatments was insignificantly different from the first to 3rd day after the treatment but was significantly different from the 4th to 6th day either in the mean flight duration or in distance. Evaluation of the long fliers at the same stages between the treatments also supported this finding. Flight capacity of the JHM‐treated moths also differed with the sex. The JHM‐treated female did not fly less than the control from day‐1 to day‐3, but did significantly less from day‐4 to day‐6 after the treatment. The flight capacity of the JHM‐treated males, however, was not weaker than that of the control throughout the test period. Comparison of the levels of energy substances in the JHM‐treated adults and the controls showed that JHM may directly acted on metabolism of glyceride, which in turn affected flight capacity. Furthermore, higher levels of glyceride in the treated male adults raised their flight capacity to a stronger levels than the control in most of the days of tethered‐flight test period. Contents of glycogen, however, were insignificantly affected by JHM in both male and female adults. In might therefore be concluded that levels of JH is a critical factor regulationg migratory behavior in the army worm moth. In addition to affect metabolism of glyceride, other possible physiological roles that JH played in determining migrattory behavior are also discussed.