| The big-eyed bug, Geocoris pallidipennis Costa (Heteroptera:Lygaeidae), a predaceous predatorand an effective predator for the pests of cotton, can prey on the nymphs and eggs of aphid,thrips,leafmites,plant hopper and leafhopper, so it is a potential natural enemy insects. It is an important naturalenemy for mass rearing and could be used to control the pests in cotton field. Predation and biologicalcharacteristics of G. pallidipennis has been studied, however, there is no research on rearing in vitro andartificial diets of the big-eyed bug. In this study, the big-eyed bug was fed on Corcyra cephalonicaStainton eggs, which could set the theoretical foundation for mass rearing. The rearing results wereevaluated by the development duration,survival of the nymph and other physiology parameters. Thehemolymph in oak silkworm pupa supplied the main protein for artificial diets. The methods of nutritionand biochemistry of insects were used to assess the formula of the diets and the rearing result. On theother hand, component content of artificial diets was analysed. The purpose of this experiment was togrope the possibility of mass rearing of G. pallidipennis Costa in artificial diet, which will provide thereferences for large-scale rearing of G. pallidipennis Costa and other predatory bugs. The study resultsas follows:The big-eyed bug was fed with Aphis glycines, C. cephalonica Stainton eggs, C. cephalonicaStainton eggs combined with Phaseolus vulgaris leaves. The results which were evaluated according tothe development duration,survival of the nymph,adult weight,sex ratio and adult fecundity showedthat the optimum food was C. cephalonica Stainton eggs combined with P. vulgaris leaves. Thebig-eyed bug fed with C. cephalonica Stainton eggs combined with P. vulgaris leaves could developedsuccessfully from first generation to third generation. It proved the possibility of rearing in vitro.Antheraea pernyi Geurin-Meneville chrysalis were processed into four styles, the water extract,defatted powder, dreezing powder and full-fat powder, as one of the main components of the artificialdiet. Besides, sucrose, corn oil, dry buttermilk and yolk was added into the diet as the other components.First instar nymphs fed on each of the four diets developed to audlt stages. Among these diets, diet withwater extract of G. pallidipennis Costa was the best formulation, which could fulfil the nutrientrequirement for growth and reproduction of G. pallidipennis. The development duration, preovipositionof G. pallidipennis fed on the diet with water extract was34.42±0.80d and7.80±0.33d respectively,which was significantly different with control. The weight of male and female, oviposition per female,egg viability of G. pallidipenni fed on the diet with water extract was1.88±0.05mg,2.90±0.04mg,46.10±1.85,0.80±0.04, which had no significangt difference with control.The average consumption of A. glycines and C. cephalonica Stainton eggs per day by audlt and4thand5th instar nymphs of G. pallidipennis fed on the water extract artificial diet was recorded in thisstudy. The results showed that there were significant differences between both the consumption of A.glycines and C. cephalonica Stainton eggs by female fed on the water extract artificial diet and theconsumption of A. glycines by5th instar nymph on the water extract artificial diet with control. G. pallidipennis population was reared on the water extract artificial diet from first generation to thirdgeneration successfully.The nutrient components of artificial diets which mainly include crude protein and crude fat wasanalyzed. The crude protein and crude fat in artificial diet was15.76%and24.61%, however, the crudeprotein and crude fat in C. cephalonica eggs was52.94%and35.13%. The result illustrates that thewater extract artificial diet was inferior to the C. cephalonica eggs, and needed to be improved andoptimized. |
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