Study On Artifical Diets For Rearing Larvae Of Harmonia Axyridis(Pallas)

With the introduction of the conception of green plant protection, natural enemies of insects are increasingly used in agricultural production. As the most potential natural enemy of insects, Harmonia axyridis(Pallas) are attracting more and more people’s attention. It belongs to Coleoptera which is native to Asia and widely distributed in Europe, America and so on. It has the feature of a wide range of feeding, long life, and strong patience. The mass artificial rearing of Harmonia axyridis(Pallas) of great significance for the promotion of green plant protection, the sustainable and effective management of insect pests, the protection of ecological agricultural environment, the improvement of the quality of agricultural products. However, there is no artificial diet in market which enables Harmonia axyridis(Pallas) to meet needs for growth and reproduction in the process of commercial production. Besed on this, the thesis studied the following aspects:through the modification of original artificial diet added with exogenous protein insect, the theoretical formulation was subjected to verification of biological and biochemical aspects, the effect of artificial feeding was systematically evaluated. The main results were as follows:At first, the selection of artificial feed additives to larvae of Harmonia axyridis(Pallas) was given. The experiment divided the sample into three groups: maggot group, yellow meal worm group and basic food group. The results showed that the larvae of the three groups can complete the development from egg to adult. Combined the comprehensive indications of larval development duration, pupa, the weight and gain of adult with other indicators, the thesis conducted results the maggot group was significantly better than the yellow meal worm group and basic feed group, but lower than the aphid group. It showed that the larval developmental duration of Maggot group was 17.09 days, pupa was 6.50 days, body weight of female adult was 0.261 gram and male adults was 0.239 gram, the larvae acquire percentage was 96.67%. Based on this, the maggots group was selected as artificial feed additives to larvae of Harmonia axyridis(Pallas).Then, the thesis made the research of orthogonal optimization of artificial feed formula. Experimental results showed that different indicators made varying degrees diff- erence through rangeanalysis and variance analysis.And optimized formulation was got by carrying out Ducan results of Orthogonal Trial, which was consist of 0.5 gram of liver, 0.15 gram of maggot powder, 0.15 gram of yeast extract, 0.2 gram of sucrose, 0.2 gram of honey. The results of testing the optimal theoretical formulation showed that its effect was better than the results of orthogonal experiment and the theoretical formula had the advantage over the basic feed formula in the parts of the stage of larvae and pupal, the survival rate of larvae, adult weight and other indicators. The larval survival rate was above 90% and there was no significant difference from the compared. The stage of larvae in the theoretical group was significantly extended around 3 days than the compared.Next, the thesis made the research of the effect of fecundity and predation of Harmonia axyridis(Pallas), which was made by optimum formula. The results showed that the larvae feed had an impressive impact on the fertility of Harmonia axyridis(Pallas) adults. The oviposition of the group using artificial feed to larvae Harmonia axyridis(Pallas) was 79.84%, which was significantly lower than the group using aphids feeding. There was no significant difference in the period of preoviposition, spawning and life expectancy of male between the two groups. The egg hatch ability of group using artificial feed to the larvae of Harmonia axyridis(Pallas) was significantly lower than the group using aphids feeding, although the hatching rate of the former still remained above 80%. There was no remarkable difference in the fields of fecundity and life expectancy of female between the two groups. The prey response to Harmonia axyridis(Pallas),which was fed different diets when they were larvae, could all meet disc equation of HollingⅡ.The predation of the group of four instar larvae was significantly higher than the group using artificial diet and there was no big difference between male and female adult using different treatments. With the increase of prey density, the searching effect of Harmonia axyridis(Pallas) declined. Three optimal densities for searching of Harmonia axyridis(Pallas) were determined in the group using artificial feed, which were 1: 10.63, 1: 20.14, 1: 14.69. As for the compared group, they were 1: 20.66, 1: 22.98, 1: 12.48. Both of them had instructive meaning for timely release of Harmonia axyridis(Pallas) and the maximization of its controlling consequence.Finally, the results of the effect of using optimization formula to the ingredients of the larva body composition indicated that the water contents of insects in the compared group was significantly higher than the group using artificial diet. The measurement results of the crude protein between the two groups can be concluded that the crude protein in group using aphid was 10.74% and the group using artificial diet was 9.78%, the difference between the two groups was not significant. However, there was significantly difference in crude fat between the two groups and the group of using artificial diet was only about 2/3 of the compared group.