Abstract: The development period, survival rate and fecundity of natural population of Hydrellia sasakii 1-5 generations were studied in 1993 - 1995. The results show that the duration of first generation was the longest, the third and fourth generations were the shortest. The hatching rate of egg and the survival rate of larva were the smallest at first generation. It is higher at second to fifth generation. The survival rate of pupa of first generation was the lowest and hereafter increased generation by generation. The sex ratio of adults were 1: 1 around. The precede period of egg oviposition was 2 d or so at first generation, 1. 4 d at second generation and 1 d or so at third to fifth generation. There were no significant differences among the number of egg oviposition of female at second to fifth generation. It averages 24 granules or so per female. At first generation, it is less than 21. 9 granules per female. The longevity of adults of first generation was the longest and hereafter shortened generation by generation. The population trend index of fourth generation was the largest and that of first generation was the smallest. Ichneumonidae is a natural enemy of Larva. Tetrastichus hydrellia and Braconidae are natural enemies of pupa.

Key words: duration, fecundity, Hydrellia sasakii, natural populatloni survival rate

摘要： 1993～1995年在田间观察了稻茎毛眼水蝇1～5代的发育历期、存活率和繁殖力。结果表明，各虫态所期以第1代最长，第3、4代最短。卵孵化率、幼虫存活率均以第1代最低，其余各代较高。蛹存活率以第1代最低，以后逐代提高。成虫性比接近1：1。产卵前期第1代2d左右，第2代1.4d，第3～5代1d左右。成虫产卵量第2～5代差异不大，平均24粒／雌左右，第1代较少，为21.9粒／雌。成虫寿命以第1代最长，以后还代缩短。种群趋势指数以第4代最大，第1代最小。幼虫期寄生性天敌主要是姬蜂，蛹期天敌有2种，分别为稻茎水蝇啮小蜂和茧蜂。

关键词: 稻茎毛眼水蝇, 自然种群, 历期, 存活率, 繁殖力