Comparison of biological characteristics between the natural population and the laboratory population of the oriental fruit moth,
Grapholita molesta (Lepidoptera: Tortricidae) GUO Li-Na, FANG Cheng, LI Yi-Ping, XU Xiang-Li, WU Jun-Xiang
Related Articles |
【Aim】 Differences in biological characteristics between the natural population collected from the wild and the laboratory population reared more than 50 generations of the oriental fruit moth,
Grapholita molesta (Busck), were investigated to estimate if the laboratory population has the evidence of degeneration. 【Methods】 The main biological characteristics of the natural and laboratory populations of G. molesta bred under the same indoor conditions were investigated respectively and their life table parameters were comparatively analyzed. 【Results】 The results showed that the pupal stage of the laboratory population was extremely significant longer than that of the natural population ( t=-10.78, df=4, P=0.0004), and the egg stage, larval stage and pre-pupal stage of the laboratory population were slightly longer than those of the natural population. The larval survival, pupation and eclosion rates of the laboratory population were extremely significant higher than those of the natural population (larval survival rate: t=-7.61, df=4, P=0.0016; pupation rate: t=-24.32, df=4, P=0.0017; eclosion rate: t=-6.96, df=4, P=0.0022), but there was no significant difference in egg hatch rate, pupal weight, the longevity of female and male adults, pre-oviposition duration, oviposition duration as well as the number of eggs laid per female between the two populations. The rate of fruits bored by the natural population was slightly higher than that bored by the laboratory population. The results of life table showed that the population trend index ( I), the net reproduction rate ( R 0), the intrinsic rate of increase ( r m), the mean generation time ( T), and the finite rate of increase (λ) of the laboratory population were extremely significantly higher than those of the natural population ( I: t=-12.20, df=4, P=0.0003; R 0: t=-11.72, df=4, P=0.0003; r m: t=-9.77, df=4, P=0.0006; T: t=-12.05, df=4, P=0.0003; λ: t=-9.79, df=4, P=0.0006), but the population doubling time ( D t) of the laboratory population was extremely significantly lower than that of the natural population ( t=7.17, df=4, P=0.0020). 【Conclusion】 After domestication of more than 50 generations, the laboratory population, whose life table parameters and damage rate do not decline, shows a better adaptability and a greater population growth potential than the natural population. Our results suggest that the laboratory population can be a preferred material for conducting experiments.