甜菜夜蛾核多角体病毒对斑痣悬茧蜂发育及存活的影响

Survival and development of Meteorus pulchricornis in nucleopolyhedrovirus-infected larvae of Spodoptera exigua

研究了甜菜夜蛾核多角体病毒对斑痣悬茧蜂Meteorus pulchricornis发育及存活的影响。正在蜕皮的甜菜夜蛾Spodoptera exigua 2龄幼虫被斑痣悬茧蜂寄生后,当其发育到3龄与4龄时分别饲以95%致死浓度(LC_(95))或10×LC_(95)甜菜夜蛾核多角体病毒(SpeiNPV),研究表明:甜菜夜蛾核多角体病毒对斑痣悬茧蜂发育及存活产生不利的影响,影响程度取决于寄生与饲毒的间隔期以及饲毒量。被寄生的甜菜夜蛾幼虫发育到第3龄(即被寄生后第1天,1dpp)分别饲以LC_(95)或10×LC_(95) SpeiNPV的处理,没有寄生蜂老熟幼虫从寄主体内钻出;被寄生的甜菜夜蛾幼虫发育到第4龄(4 dpp)分别饲以LC_(95)或10×LC_(95) SpeiNPV的处理,分别有25.62%与16.31%寄生蜂老熟幼虫从寄主体内钻出。甜菜夜蛾是否饲毒对寄生蜂的出蜂率、化蛹率及羽化率影响显著;饲毒浓度影响寄生蜂的出蜂率、化蛹率,但不影响羽化率。甜菜夜蛾饲毒与否对寄生蜂幼虫及蛹的发育历期无显著影响,但饲毒甜菜夜蛾体内寄生蜂幼虫、蛹及成蜂显著小于未饲毒的甜菜夜蛾体内寄生蜂幼虫、蛹及成蜂。

The survival and development of the parasitoid Meteorus pulchricornis in nucleopolyhedrovirus(NPV)-infected Spodoptera exigua larvae were investigated. The second molting stage of S.exigua larvae were parasitized by M.pulchricornis and subsequently exposed to a 95% lethal concentration(LC95) or 10×LC95 of S.exigua NPV(SpeiNPV) during the third or fourth instars. Infection of S.exigua larvae with SpeiNPV was deleterious to the survival and development of M.pulchricornis. The survival of M.pulchricornis in SpeiNPV-infected S.exigua larvae was dependent on the interval between parasitization and virus inoculation, as well as on the inoculation dose of SpeiNPV. No parasitoid larvae emerged from the host when the parasitized host larvae were exposed to LC95 or 10×LC95 of SpeiNPV during the third instar, which was the first day post-parasitization(1 dpp), but 25.62% and 16.31% of parasitoid larvae emerged, respectively, when on the exposure took place during the fourth instar(4 dpp). There were significant differences in the percentages of parasitoid emergence, pupation and adult eclosion between parasitoids developing in SpeiNPV-infected hosts and those in non-infected hosts. Inoculation dose also affected parasitoid emergence and pupation, but did not affect parasitoid adult eclosion. No significant differences were found in the durations of parasitoid larvae and pupae between parasitoids that developing in SpeiNPV-infected hosts and those in non-infected hosts. Body sizes of parasitoids developing in SpeiNPV-infected hosts were significantly smaller than those in non-infected hosts.