|Budget Amount *help
¥2,100,000 (Direct Cost : ¥2,100,000)
Fiscal Year 1995 : ¥600,000 (Direct Cost : ¥600,000)
Fiscal Year 1994 : ¥1,500,000 (Direct Cost : ¥1,500,000)
The common cutworm, Spodoptera litura does not enter diapouse in any developmental stages, but it can hibernate in greenhouses in south-western part of Japan like Saga. So, it has been generally accepted that the occurrence of this insects in various places in Japan would be induced by the immigrant originated from the hibernating population. But, in Saga the fluctuation patterns of the males caught by pheromone trap clucidated by the present stuby considerably differed from those estimated theoretically from the effective accumulative temperature of this insect. Further, the number of males caught tended to increase suddenly when typhoon approached or passed in late August and early September, but the previous prevarence of the larvae which might be expected to induce such a sudden occurence of the adults could not observed in the fideld. The seasonal prevalences of the male adults caught by pheromone trap were similar between Saga and Kagoshima, the most southern part of Kyushu Island, where males were also sscaught in unusually large number at the time of typhoon attack. In this research, haemolymphs were collected rfom the male adults caught by pheromone trap at various seasons, and assayd for flight energy sourse remained. It was found the individuals with considerably low levels of trehalose, the major carbohydrate in haemolymph and of diacylglycerol in lipophorin, the lipoprotein carrying lipid, came to be predominant, prominently when typhoon or depression passed. The proportion of individuals with highly dameged wings increased in these times. While in October when the larvac damaging vegetables came to be observable in various areas, the males with high level of diacylglycerol in lipophorin increased in propotion. These results support that the outbreake of this insect in September and October is induced mostly by immigrants overseas.