Flight Mode And Allocation Rule Of Energy Resources On Promoting The Reproduction Of Mythimna Separata(lepidoptera: Noctuidae)

The oriental armyworm, Mythimna separata(Walker)(Lepidoptera: Pyralidae) is a typical season-al migrant pest. It causes heavy loss to food production in China through annually roundtrip migration between southern and northern. The researchers in our country has a series of important achievements in ecology, physiological, genetic characteristics and so on of migration behavior of M.separata during the past decades, however little is known about the relationship and mechanism in armyworm migration whether result in the insect population outbreak. such as, the M.separata when to take off and how many nights to flight for landing reproduction, which whether have influence on reproduction、population and disaster outbreak have not reported so far. Therefore, we has a system research on the habits of landing compensatory nutrition in the day and flight within 12 h on the night through simula-tion armyworm in nature, and reveal different tethered flight times gives influences on reproduction and physiological mechanism of armyworm, in order to further clarify migration behavior characteristic of the armyworm. The results were summarized as follows:1.It is cleared that the effect of flight on the reproduction and adult longevity of the adult moths and the best flight mode on promoting the reproduction.the results reveal the main mech-anism of the M.separata result from migration(1) Effect of different tethered flight durations of 1 day on the reproduction and adult longevity. newly emerged M. separata adults have a moderate flight potential, and there was no significant in-crease in flight duration, flight distance or flight velocity when adults were subject to tethered flight for more than 9 h. Flight on day 1 after emergence significantly accelerated reproduction in M. separate but this effect decreased significantly following prolongation of tethered flight duration.(2) Effect of different tethered flight nights on the reproduction and adult longevity. the re-sults of flight capacity revealed that flight duration and distance was gradually increased since the first flight started,the flight capacity of flying for 4 times was maximum, more while more than 4 times flight significantly decreased. Besides, the preoviposition period of the M..separata that flighted 1 and 2 nights was significantly shorted, Lifetime fecundity of the moths flying for 4, 5 and 6 nights was sig-nificantly less than controls,but flying for less than 3 nights had no markedly difference.Because the habits of landing compensatory nutrition in the day and flight within 12 h on the night in nature, Therefore, we conclude that flight within 3 nights and 9 hours in the night may be the optimal flight nights of the M..separata moths in pursuit of the largest populations fertility,the possibility of flying more than 3 nights migration was less likely.2. Effect of different flight nights tethered treats on the ovarian developpent grade and mating. T the moths experienced flying 3 nights test was signicantly increasing compared with control, besides, the ovarian development grade of the female moths after flying 3 nights 1~2 day was also higher than controls in the same age. In addition, the mating frequency of female moths were less than the controls since the mating started,until 2 day after flying 3 nights,the flown group surpassed the con-trols,. The above results show that flying for1-3 nights promote the ovarian development and mating of Mythimna separata. female moths3. Effect of different flight nights tethered treats on the triglyceride content. The results indi-cated that the triglyceride content of all flown female moths had significantly less than controls in the same age and decreased with the increasing of flight nights, the triglyceride content of flying 3 nights was the least,moreover, after flight 3 nights 1 and 2 day had an extent increasing and significantly ex-ceeded than just flying 3 nights. These results indicated that the consumption of triglyceride is more than the supplement during migration, the more flight times, the lower triglyceride content, however, the triglyceride content of unflown moths begun to participate in the construction of the reproduction sys-tem, hence, we speculated that the best flight nights should not be more than 3nights.4. Effect of different flight nights tethered treats on the protein content. The results indicated that The thorax protein content gradually decreased since the first flight, the flying for 3 nights s was least, subsequently, it would gradually increased and the moths after flying 3 nights significantly more than just after flying 3 nights. For ovarian protein content, in flown group, the moths just flying for 1 or 2 nights significantly loss than unflown moths in the same age. These results show that the protein con-tent was involved in flight muscle development, however, the protein content raised after 1~2 day at the end of flying, that is because flight would promote the ovarian development, which leads to protein level increasing in ovarian.