| Orius similis Zheng(Hemiptera:Anthocoridae)is a kind of promising predatory insect in the major regions of agriculture.Present research in artificial diets for O.similis still remained some unsolved problems,such as low survival rates of older nymph and slow development of ovary.This article focused on the effects of an artificial diet(The main ingredients are egg yolks,honey and flyblow albumen powder)on the biological characteristics and predation of O.similis.On this basis,we analyzed the growth and development of O.similis fed on diets containing different proportion of animal-source diets(A.craccivora)in a short term to provide theoretical basis for improvement of the artificial diet and large-scale artificial propagation.The main results were as follows:1.The effects of the artificial diet and the natural prey Aphis craccivora on the biological characteristics of O.similis.The results showed that O.similis fed on artificial diet could complete a whole life cycle and little eggs were laid.Young larvae possess a high survival rate on the artificial diet,while the survival rate of elder larvae fed on artificial diet was significantly lower.The artificial diet had significant influences on the development of O.similis.O.similis fed on artificial diets has lower eclosion rate and fecundity.The feeding experiences of both nymph and adult have significant effect on the fecundity of females.2.The effects of the artificial diet and the natural prey on the predatory behavior of O.similis.The results showed that the predation model of larvae and adults fed on both foods were belonging to the Holling ? model.The theoretical maximum preying amount of O.similis five instar nymphs and adult which fed on artificial diets is 40,40 while those of which fed on natural prey is 41,35.Those results indicate that O.similis five instar nymphs and adult do not cope with the lack of nutrition by increasing the daily predation amount.The searching efficiency of O.similis fed on different foods shows no significant difference when prey density was the same.The searching capacity is decreasing with the prey densities.Therefore,our improved artificial diet could be applied in large-scale artificial propagation.Moreover,O.similis fed on artificial diet with low prey density performs better in pest control.3.The growth and development of O.similis fed on diets containing different proportion of animal-source diets in a short term.The 4th nymphs have significantly shorter duration when fed on animal-south food than those fed on artificial diet,while the case is different in 5th nymphs which shows no significant different when fed in both diet.Survival rate of O.similis 5th nymphs shows no significantly different in different proportion of the food ingredient and the survival rate of each group was more than 90%.In fourth instar nymphs short-term treatment,ovary tube length of 7d instar O.similis adult is 700-1000?m longer than artificial diets group(666.79?m),while still shorter than natural prey group(1066.45?m).In fifth instar nymphs short-term treatment,the ovary tube length has no difference with the natural prey group when added 4 preys in the diet.When the number of added prey over 8,the ovary tube length reach the maximum(1304.00?m)which equal to the ovary tube length of 10-day age O.similis fed on natural prey.Those results show that animal-source nutrition could accelerate the development of ovary and the accelerate rate was correlate to the added amount.Fifth instar nymph short-term treatment can significantly improve the quality of ovarian development,and a certain amount of prey can accelerate the rate of female ovary development. |
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