Abstract: The preoviposition period (POP), fecundity, copulation and longevity of the migratory oriental armyworm moth, Mythimna separata (Walker), as influenced by tethered flight were investigated in the laboratory. The moths flown for 6, 12, 18 and 24 hours at day-1 after emergence began oviposition 1-2 days earlier than the unflown ones, and the difference was significant. Life time fecundity of the moths flown at this age for various periods was also greater than that of the control indicating that flight can enhances the reproduction capacity of the moths. The reproductive parameters, however, differed greatly in the moth following 23-5hours tethered flight at different ages after emergence. POP of the moths flown at day-1 was not only significantly shorter than that of the control, but also than that of the moths starting to fly from day-2 to day-5. POP of the moths flown at day-5, however was significantly longer than that of the control. Life time fecundity of the moth showed close relation to the age of the moths starting to fly. The earlier the moths started to fly after emergence, the greater the fecundity they had. When the moths flown at day-5 after emergence, for example, their life time fecundity was only half of that in the control and half less than that in the moths flown at day-1, exhibiting an oogenesis-flight syndrome. Relationship between flight distance and the total fecundity of the moth differed greatly as the age of the moth starting to fly varied. Fecundity in the moth flown farther or longer was greater than those flown shorter when the moth was tested at day-1 to day-3. The situation, however, got reverse when the moth was starting to fly at day-4 and day-5. Regardless of flight age of the moth, the oviposition peak of the flown moths occurred 1 day earlier than that of the moth without tethered flight. Longevity, mating percentage of the moths undergone flight were insignificantly different from that of the controls, except the mating percentage of the moth flown at day 5 was lower. The ascent period of the moth for migration, significance of flight or migration in the life history, population dynamics and outbreaks of the oriental armyworm are discussed on the results obtained together with the lights of published findings.

Key words: Mythimna separata, flight/migration, oviposition, longevity, fecundity