两近缘种烟草上棉铃虫种群适合度的比较研究

A comparative study of the population fitness of Helicoverpa armigera (Hübner) on two tobacco species,Nicotiania tabacum and N. rustica

分别在室内和自然条件下,比较研究了普通烟草和黄花烟草两种不同寄主植物上棉铃虫生长发育、食物转化和利用及种群增长情况。结果表明:(1)室内26±1℃、75%±5%RH和16L∶8D光周期条件下,与普通烟草相比,黄花烟草上幼虫的发育历期显著延长,1龄和2龄幼虫的存活率及雌蛾产卵量显著下降,种群净增殖率(R0=30.5374)和内禀增长率(rm=0.0951)减小;(2)6龄幼虫对两种烟草的近似消化率及其相对生长率无显著差异,但对黄花烟草的利用率和转化率显著下降,相对取食量显著提高;(3)第2代棉铃虫在普通烟田的种群增长(I=1.9922>1)比黄花烟田(I=1.1581>1)快,"烟草和其他"对种群起主要控制作用,特别是对低龄幼虫;第3代棉铃虫在普通烟田的种群增长有所减慢但仍呈上升趋势(I=1.5994>1),而在黄花烟田则呈下降趋势(I=0.6434<1),低龄幼虫受烟草抗性和雨水等的影响较大,高龄幼虫被病菌感染的数量增多。这些结果表明,与普通烟草相比,黄花烟草不适合棉铃虫种群的增长和繁殖。

Effects of Nicotiania tabacum and N. rustica on the development, food utilization and population growth of Helicoverpa armigera （Hǔbner） under both experimental and natural conditions were studied comparatively. The results showed that ： （1） In laboratory condition with 26±1℃, relative humidity of 75%±5% and photoperiod of 16L：8D, when reared on N. rustica, the development duration of H. armigera larvae significantly prolonged, while the survival rate of both 1 st and 2nd instar larvae and the fecundity of female adults reduced notably, the net reproductive rate （R0 = 30.5374） and innate capacity of increase （rm = 0.0951 ） decreased compared with those reared on N. tabacum. （2） There were no significant differences in the approximate digestibility （AD） and the relative growth rate （RGR） of the 6th instar larvae reared in the two tobacco species. Compared to the larvae feeding on N. tabacum, both the efficiency conversation of ingestion （ECI） and digestion （ECD） to N. rustica significantly decreased, while the relative consumption rate （RCR） increased significantly. （3） The 2nd generation population of H. armigera in N. tabacum fields （ I = 1. 9922 〉 1 ） increased faster than that in N. rustica fields, which were influenced mainly by “tobacco and others”, especially in early stage of larvae. The increase of the 3rd generation population slowed down in N. tabacum fields （ I = 1. 5994 〉 1 ）, which declined in N. rustica fields （ I = 0. 6434 〈 1 ）. The early stage larvae were mainly affected by tobacco resistance and rainfalls, while the late stage larvae were infected easily by pathogens. These results showed that N. rustica was less suitable to the reproduction and increase of H. armigera compared to N. tabacum.