| Nesidiocoris tenuis Reuter (Heteroptera: Miridae), is a common omnivorous plantbug of agroecosystems and is known to be a predator of whiteflies, thrips, aphids and several other pest species. N. tenuis contributes to the control of small arthropod pests in vegetable crops, so scholars at home and abroad pay more and more attentions on biology control of N. tenuis in protected crops. There have been some researches on predation functional response, biological characteristics and so on. Currently, there is no report on artificial diets of N. tenuis at home and abroad. In this paper, component content of rice moth(Corcyra cephalonica) eggs is analysed, and using the result to prepare artificial diets and determine the optimum reagent type of artificial diets. The protein in oak silkworm pupa is used as exogenous animal protein. According to analyse the component content of rice moth eggs and artificial diets, the artificial diets are improved and more suitable for growth and development of N. tenuis. The predation response and continuous rearing are used for evaluation of the optimum formula of the diets, which provide the references for large-scale rearing of N. tenuis and research on artificial diets of other omnivorous mirid. The experiment results as follows:Assay the nutrient components of rice moth eggs, which mainly include contents of crude protein, crude fat and sugar. The result is crude protein 52.94%, crude fat 35.13%, sugar 4.26%. The artificial diets of N. tenuis are prepared according the result. Three forms are adopted, i.e. full-fat power of oak silkworm, defatted power of oak silkworm, homogenate of oak silkworm and liquid diet packaged by paraffin is used for feeding N. tenuis.Analyse the principal components of three artificial diets and select an adapt artificial diet for growth and development of N. tenuis. The result shows: the optimum is homogenate of oak silkworm which can meet the essential nutrient requirement for growth and reproduction of N. tenuis and full-fat power of oak silkworm, defatted power of oak silkworm are second to homogenate of oak silkworm. However, N. tenuis fed on the homogenate of oak silkworm is inferior to the control in larva duration, survival rate, adult reproduction, and need to be improved and optimized.The biochemical analysis of rice moth eggs and homogenate of oak silkworm revealed that, although artificial diet D1 is composed mainly of proteins and fat, there was a deficiency of total amino acids and free amino acids. Fatty acid concentration was significantly inferior in palmitic acid than control, and was higher in linoleic acid andα-linolenic acid, and there was no significant difference in other fatty acids.In order to obtain better rearing effect, D1 was modified according to mix yeast hydrolyate or casein hydrolysate. N. tenuis fed on modified diets was significantly inferior to control, and even below D1. Nymphal development time was longer than in rice moth eggs and D1 reared insects. There was no significant difference in survival rate, but at the beginning of 5 instar, the percentage of nymphal survival is vary considerably. No significant differences in adult weight were detected in males in the modified diets, although there were significant differences in the control population, with males weighting more lighter than females. No differences in preoviposition period and fecundity were found in adult of the control and modified diets. Females reared on modified diets are better than that from D1, especially mix the yeast hydrolyate, which revealed that the modified diets are good for N. tenuis, reproduction. But probably further improvements of the modified diets in improving duration, percent of nymphal survival and weight could be done after further investigations.We compared the predation efficiency of N. tenuis produced on D1 with those reared conventionally on rice moth eggs and tomato plants. Their performances were evaluated on two prey, the greenhouse whitefly Trialeurodes vaporariorum Westwood (Homoptera: Aleyrodidae) and the Myzus persicae Sulzer (Hemiptera: Aphididae). Their tendency to cannibalistic behavior was also evaluated. Nymphs of N. tenuis produced on the conventional method consumed more number of greenhouse whitefly pupae to nymphs reared by the D1 method. Diet-reared females consumed significantly more whitefly pupae after 24 and 48 hours than control females. When the aphid was offered, diet-reared N. tenuis nymphs consumed a similar number of prey to control N.tenuis. Control-reared females consumed significantly more aphids after 12, 24 and 48 hours than diet-reared females. There was no significant increase in cannibalistic behavior of diet-reared N. tenuis. These results show that the predation efficiency and the tendency to cannibalism of diet-reared N. tenuis is similar to that of conventionally-reared individuals. |
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