关键词: 圆形分布法, 蝇类, 季节消长

Abstract: Objective To find out the peak day and the peak periods of the seasonal change in numbers of flies,so as to work out a scientific plan for controlling and preventing the flies. Methods The round distribution method was used to analyze the datum collected from the years of 1998 2000 to monitor the change in numbers of flies. Results It was showed that in Chifeng urban district,the peak day of the seasonal change in flies was July 13th during the years of 1998 2000; but in the single year. It was July 20th in 1998,June 30th in 1999 and July 23th in 2000. The peak period of the seasonal change in flies were from May 25th to Sep 1st during the years of 1998 2000,however,in the single year. It was from May 31th to Sep 7th in 1998,from May 15th to Aug 16th in 1999 and from June 3th to Sep 12th in 2000. Conclusion The change in numbers of flies has a obvious seasonal feature during the years of 1998 2000. The round distribution method is suitable to analyzing the seasonal change in numbers of flies.