Studying On Behavior, Physiology And Biochemistry Of Nutrition Of Geocoris Pallidipennis (Costa)

Geocoris pallidipennis (Costa) is an important predator in cotton agroecosystem in China. A fewcharacteristics of morphology, biology and ecology of G. pallidipennis were reported. However, nosystematic studies about the influence of food on nutritional physiology and biochemistry of G.pallidipennis yet, Thus, The characteristics of biology, enzymatic activity, nutritional content andpredation on M. persicae were studied for G. pallidipennis fed on artificial diet based on non-insect andthe Myzus persicae (Sulzer). This research will define the influence of food on the growth andreproduction of G. pallidipennis, and providing theoretical basis for the large-scale rearing of G.pallidipennis.The main results were as following:1. G. pallidipennis was provided artificial diet and M. persicae in the laboratory. The parameters ofbiology were used to evaluate the effect of rearing. The results showed that both the artificial diet andprey can meet the need of nutrition to compete the development and reproduction of G. pallidipennis.The pre-oviposition, total oviposition and the ration of female adult were not affected by the food. Butthe nymphal duration of G. pallidipennis fed on artificial was24.5days significantly shorter than onprey27.4days. The oviposition predation on artificial diet was also significantly longer than on prey.The G. pallidipennis fed on artificial diet performed excellently at weight and longevity. But thecumulative survival rate of each instar on prey was significantly higher than on artificial diet..2. The protease (including protease, typsin, chymotrypsin-like and aminopeptidase enzymes),carbohydrates enzyme (including trehalase and amylase) and lipase activity of G. pallidipennis fed onartificial diet and prey were measured. The results showed the food had no significant effect on the totalprotease while the significant influence on the special protease. G. pallidipennis on artificial diet showedhigher activity of trypsin-like enzyme while the lower level of chymotrypsin-like and aminopeptidaseenzymes. The male adult had higher activity of trehalase than female adult. And there was higher onprey than artificial diet. The male adult on artificial diet had the highest activity among the treats. Thefemale adult had higher level of lipase than male adult. Different food conditions produced differenteffects on the enzyme activity of G. pallidipennis.3. The content of protein, carbohydrate and fat of G. pallidipennis reared on artificial diet and preywere assayed. The results showed there was a significant increasing of the protein of female adult, butno significant difference of male adult. The content of yolk protein of each female adult was687.3ngand679.0ng having no significant difference on artificial diet and prey, respectively, accounting for37%and34%of the soluble protein. There was no significant effect of artificial diet on the content ofglucose, while a significant decrease of glycogen. The female adult had higher level of fat than maleadult. There was a significant difference between the male adults but the female adults under thedifferent condition.4. The results showed that all the stages of G. pallidipennis attacked the M. persicae had a potentialcontrol on the aphids, showing a type Ⅱ functional response at the prey densities tested.The nutritional history had significant influence on the predation ability of G. pallidipennisnymphs but the female adult. The predation of3rdand4thinstar nymphs of G. pallidipennisobtained from M. persicae on M. persicae at the high density of M. persicae was higher thanreared on artificial diet, while the5thinstar nymphs of G. pallidipennis showed inversely.The search ability of G. pallidipennis on M. persicae increased with the growth of G.pallidipennis and decreased with the density increased of M. persicae. The female adults of G.pallidipennis showed an outstanding performance than other stages whether on M. persicae or artificialdiet. There was a strong interference effect of G. pallidipennis. The predation of each predator andpredatory rate decreased with its density increased.