Bionomics of Exorista japonica（Townsend） was observed in present study.Results indicated that the rank of preference for oviposition on the tachinid（from high to low） was thorax,head and abdomen of Bombyx mori.Egg deposition on the three parts was significantly different.In choice tests,the tachinid parasitized 62.7% of the larvae of B.mori,26.15% of the larvae of Spilarctia subcarnea and 12.33% of the larvae of Hyphantria cunea.The number of eggs deposited on the larvae of B.mori,S.subcarnea and H.cunea was 5.63,4.05 and 1.85,respectively.Parasitism on the 5th,4th and 3rd instar larvae of B.mori was 44.38%,34.67% and 21.05%,respectively,and the number of deposited eggs was 9.58,7.95 and 4.45,respectively.Parasitism on the 7th,6th larvae and 5th of H.cunea was 53.33%,27.02% and 19.67%,respectively,and the number of eggs was 7.27,3.17 and 1.33,respectively.Host mortality increased with the increase of egg deposition.When one egg was deposited,pupation of tachinid was 52% and host mortality was 58.33%;when two eggs were deposited,pupation of tachinid was 69.16% and host mortality was 71.67%;when 4 eggs were laid on host,pupation of tachnid was 76.83% and host mortality reached 100%.When more than 4 eggs were oviposited,pupation of tachinid reduced.%本研究观察了日本追寄蝇Exorista japonica（Townsend）的生物学特性。日本追寄蝇主要产卵于家蚕Bombyx mori L.幼虫的胸部,其次为头部,最后是腹部,三者间产卵量差异显著。在美国白蛾Hyphantria cunea（Drury）、家蚕和人纹污灯蛾Spilarctia subcarnea（Walker）幼虫同时存在时,日本追寄蝇优先选择寄生家蚕幼虫,寄生比率为62.79%;其次选择人纹污灯蛾幼虫,寄生比率为25.16%;选择美国白蛾最少,寄生比率为12.33%。在家蚕、人纹污灯蛾和美国白蛾幼虫体上的着卵量分别为5.63、4.05和1.85粒。该寄蝇对5、4、3龄家蚕幼虫的寄生比率分别为44.38%、34.67%和21.05%,着卵量分别为9.58、7.95和4.45粒;对7、6、5龄美国白蛾幼虫的寄生比率分别为53.33%、27.02%和19.67%,着卵量分别为7.27、3.17和1.33粒。随寄主体表寄蝇卵量的增加,寄主死亡率增加;卵量为1粒时,寄蝇化蛹率为52%,寄主死亡率为58.33%;卵量为2粒时,化蛹率为69.16%,寄主死亡率为71.67%;卵量为4粒时,化蛹率为76.83%,寄主死亡率达到100%;卵量大于4粒时,寄蝇化蛹率开始下降。
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