日本食蚧蚜小蜂对寄主的龄期选择性

Host instar preference of Coccophagus japonicus Compere

为了明确寄主龄期对日本食蚧蚜小蜂Coccophagus japonicus Compere的产卵选择及后代发育的影响,本文在橡副珠蜡蚧Parasaissetia nigra Nietner 1龄若虫、2龄若虫、3龄若虫、初期成虫、褐色期成虫、初产卵期1-2 d成虫等6个发育阶段条件下观察了日本食蚧蚜小蜂的产卵选择系数、发育历期、寄生率、羽化率及性比。结果表明:选择性产卵条件下,日本食蚧蚜小蜂对褐色期成虫的产卵量、寄生率、选择系数最高,其次为初期成虫,1龄若虫最低均为0;日本食蚧蚜小蜂在橡副珠蜡蚧2龄若虫-褐色期成虫体内能完成世代发育,发育历期以褐色期寄主最长(24. 0 d),2龄若虫最短(22. 1 d);羽化率以3龄若虫最高(99. 12%),雌性比均为1。综合考虑,可选用橡副珠蜡蚧初期成虫及褐色期成虫作为日本食蚧蚜小蜂的室内扩繁寄主。

To determine the effects of host instar of Coccophagus japonicus on the oviposition selection and offspring development. The oviposition selection rate,developmental duration,parasitism rate, emergence rate and female ratio in offspring of P. nigra were studied at the stage of the first instar,the second instar,the third instar,adult at early stage,adult at brown stage and adult at 1-2 days after oviposition. The results showed that the parasitic rate, egg number and selection coefficient of C. japonicus was highest on P. nigra adult at brown stage in choice tests. It's followed by the adult at early stage. The lowest parasitism was observed on 1st instar (0). C. japonicus were able to complete life cicle from 2^nd instar to adult of brown stage. The development duration of offspring was the longest in adults at brown (24.0d) and the shortest in the 2^nd instar ( 22.1d). The highest emergence rate in the 3rd instar (99.1%). The female ratios were 1. In conclusion,the adult at early stage and the adult at brown stage were more suit for mass rearing of C. japonicus.