4种寄生蜂在草地贪夜蛾卵上的种群增长潜能及优势蜂种间竞争

Population growth potential of four parasitoids on Spodoptera frugiperda(J.E.Smith)eggs and interspecific competition between two dominant parasitoid species

为明确入侵性重大农业害虫草地贪夜蛾卵期优势寄生蜂种类,采用生命表方法评价了夜蛾黑卵蜂、短管赤眼蜂、螟黄赤眼蜂和松毛虫赤眼蜂这4种寄生蜂在草地贪夜蛾卵上的种群增长潜力,并观察比较了短管赤眼蜂和夜蛾黑卵蜂这两种优势蜂种在草地贪夜蛾卵上的竞争行为。结果表明,供试的4种寄生蜂对草地贪夜蛾卵均表现出良好的寄生适应性,内禀增长率(r_(m))与周限增长率(λ)从大到小依次为短管赤眼蜂(r_(m), 0.3449;λ, 1.4118)、夜蛾黑卵蜂(r_(m), 0.2842;λ, 1.3286)、螟黄赤眼蜂(r_(m), 0.1960;λ, 1.2165)和松毛虫赤眼蜂(r_(m), 0.1751;λ, 1.1913)。当夜蛾黑卵蜂与短管赤眼蜂竞争寄生同一草地贪夜蛾卵块时,两种蜂的子代羽化率均显著低于各自单独寄生时。草地贪夜蛾卵在被夜蛾黑卵蜂寄生后1 h、24 h及48 h均可被短管赤眼蜂寄生,夜蛾黑卵蜂的子代羽化率分别为21.15%(1 h)、36.68%(24 h)和25.52%(48 h),均高于短管赤眼蜂的子代羽化率10.94%(1 h)、23.13%(24 h)和5.23%(48 h);而当短管赤眼蜂先寄生时,虽然寄生后1 h、24 h和48 h的卵粒也能被夜蛾黑卵蜂寄生,但所羽化的子代均为短管赤眼蜂,羽化率分别为42.62%(1 h)、46.93%(24 h)和38.66%(48 h)。本研究表明,与螟黄赤眼蜂和松毛虫赤眼蜂相比,短管赤眼蜂和夜蛾黑卵蜂在草地贪夜蛾卵上表现出更强的种群增长潜能;夜蛾黑卵蜂与短管赤眼蜂竞争寄生同一寄主卵块时,两者寄生能力均会受到不同程度的抑制,但短管赤眼蜂的竞争力明显强于夜蛾黑卵蜂。

To select the suitable egg parasitoids to control the fall armyworm,Spodoptera frugiperda(J.E.Smith).The population growth potential of Telenomus remus Nixon(Te.remus),Trichogramma chilonis Ishii(Tr.chilonis),Trichogramma pretiosum Riley(Tr.pretiosum)and Trichogramma dendrolimi Matsumura(Tr.dendrolimi)on eggs of S.frugiperda were evaluated with the life table under laboratory conditions,and the interspecific competition between the two dominant parasitoids Tr.pretiosum and Te.remus were also evaluated.Results showed that all tested parasitoids exhibited favorable parasitic capability on the eggs of S.frugiperda.The intrinsic growth rate(r_(m))and the finite rate of increase(λ)of the four parasitoids were as follows:Tr.pretiosum(r_(m),0.3449;λ,1.4118),Te.rumus(r m,0.2842;λ,1.3286),Tr.chilonis(r_(m),0.1960;λ,1.2165)and Tr.dendrolimi(r_(m),0.1751;λ,1.1913),respectively.When S.frugiperda eggs were offered to Te.remus and Tr.pretiosum simultaneously,the emerged adults of both parasitoid species were significantly lower than that of parasitism singly.When S.frugiperda eggs parasitized by Te.rumus were offered to Tr.pretiosum after 1 h,24 h and 48 h,respectively,offspring emergence rates of Te.remus were 21.15%(1 h),36.68%(24 h)and 25.52%(48 h),which were higher than that of Tr.pretiosum(10.94%(1 h),23.13%(24 h)and 5.23%(48 h)).When S.frugiperda eggs parasitized by Tr.pretiosum were offered to Te.rumus,no matter what time intervals,the emerged adults were all Tr.pretiosum,and the offspring emergence rates of Te.Remus were 42.62%(1 h),46.93%(24 h)and 38.66%(48 h),respectively.The findings reveal that Tr.pretiosum and Te.rumus exhibit higher population growth potential than the other two parasitoids(Tr.chilonis and Tr.dendrolimi)on S.frugiperda eggs.Both parasitic abilities of Te.remus and Tr.pretiosum were inhibited significantly under the interspecific competition,however,Tr.pretiosum showed a more competitive powe than Te.remus.