狗牙根、白三叶草对淡剑纹灰翅夜蛾生长发育和繁殖的影响

利用室内饲喂法,以高羊茅分别为对照,研究狗牙根(Cynodon dacyton)、白三叶草(Trifolium repens)对淡剑纹灰翅夜蛾Spodoptera depravata(Butler)存活、生长发育及繁殖的影响。结果表明,用狗牙根、白三叶草饲喂淡剑纹灰翅夜蛾的化蛹率、幼虫成蛾率均显著低于对照组。幼虫历期显著长于对照组。用狗牙根、白三叶草饲喂幼虫时,淡剑纹灰翅夜蛾的蛹期、产卵前期、产卵期、产卵量、♀成虫寿命与对照组均无显著差异,但幼虫龄期明显增加。狗牙根、白三叶草饲喂的淡剑纹灰翅夜蛾种群增长参数与对照组相比存在明显差异:(1)世代净生殖率(R0);(2)内禀增长率(rm);(3)周限增长率(λ);(4)种群数量趋势指数(I)明显降低;世代平均周期(T)和种群加倍时间(DT)明显延长。由此可见,狗牙根和白三叶草并不是淡剑纹灰翅夜蛾喜好的寄主植物。

Effects of Cynodon dacyton and Trifolium repens on growth ,development and reproduction of Spodoptera depravata

The effects of Cynodon dacyton and Trifolium repens on survival,growth,and reproduction of Spodoptera depravata(Butler) were observed in the laboratory with Festuca arundinacea as control.The results indicated that the pupation rate and the ratio of larva developing to moth of S.depravat feeding on C.dacyton and T.repens were significantly lower than CK,and the larval stage of S.depravat feeding on C.dacyton and T.repens was significantly longer than CK.Compared with CK,pupal stage,preoviposition period,oviposition duration,mean fecundity and life-span of female adults that feeding on C.dacyton and T.repens had no significant differences,however,the larval stage increased significantly.The parameters of population growth of S.depravata feeding on C.dacyton and T.repens had significant differences to CK.The net reproductive rates(R_o),the intrinsic increase rates(r_m),the finite increase rates(λ) and the index of population trend(I) decreased significantly,whereas the mean generation times(T) and the doubling times(DT) were extended significantly.In conclusion,C.dacyton and T.repens are not suitable host plants for S.depravata.