寄主对斜纹夜蛾实验种群生殖力的影响

Fecundity of Adult Spodoptera litura Affected by Diet

【目的】斜纹夜蛾Spodoptera litura Fabricius是一种多食性害虫,繁殖能力强,全球范围内均有分布。但是寄主对斜纹夜蛾繁殖力影响机制还不清楚。开展寄主对斜纹夜蛾实验种群生殖力的影响研究,为斜纹夜蛾的预测预报以及防治提供理论依据。【方法】通过单头饲养的方法,研究斜纹夜蛾取食甘蓝、空心莲子草和地瓜后的产卵量、卵黄原蛋白(Vg)及卵黄原蛋白受体(VgR)表达的变化。【结果】幼虫取食不同寄主的成虫寿命和产卵前期没有显著性差异,但成虫的产卵量、Vg及VgR表达量有显著差异。取食人工饲料的斜纹夜蛾产卵量最多,为(889±43.0)粒,其次为取食地瓜(496±53.1)粒、空心莲子草(362±37.3)粒,和甘蓝(193±9.7)粒。取食甘蓝、空心莲子草和地瓜的斜纹夜蛾雌虫卵巢Vg和VgR的相对表达量仅为取食人工饲料斜纹夜蛾的40%～80%,且取食不同寄主的斜纹夜蛾Vg和VgR的相对表达量与产卵量呈正相关关系。【结论】斜纹夜蛾取食不同寄主后,其卵巢内的Vg和VgR表达量存在差异,从而影响到斜纹夜蛾卵子发育,最终造成其生殖力存在差异。

【Objective】Effect of forage on fecundity of the highly reproductive and widely spread polyphagous pest,Spodoptera litura Fabricius,was studied.【Method】Under the laboratory conditions,insects were raised individually on different diet or host plant to monitor the effects on the fecundity,vitellogenin(Vg)and vitellogenin receptor(VgR)of adult S.litura.【Result】No significant differences were observed on the lifespan and response of the pre-oviposition insects as they were fed on a formulated diet,Brassica oleracea,Alternanthera philoxeroides or Ipomoea batatas.On the other hand,the fecundity,Vg and VgR of the adult females differed significantly whether they were on the formulated diet(control)or the host materials.An individual adult female on the formulated diet would produce 889±43.0 eggs;whereas,one on I.batatas laid 496±53.1 eggs;one on A.philoxeroides,362±37.3 eggs;and,one on B.oleracea,193±9.7 eggs.The relative Vg and VgR transcript levels of the female moth population fed on the host materials were merely 40% to 80% of those of control.And,those measurements correlated well with the fecundity of the insect.【Conclusion】After feeding on various hosts,the titers of Vg and VgR of S.litura differed in comparison to control diet which directly affected the egg development and fertility of the insect.