| In this paper, biological characteristic, ecological characteristic, predacious function and the effect of different factors, the system of S. impressicollis and its preys, population spatial pattern, have been studied. In order to increase the numbers of S. impressicollis, Provide a theoretical basis for the protection and the use of artificial. The main results are as follows:1. The growth and survival of the larvae stage of S. impressicollis was observed at the temperature range of 19-31℃. The results show: As increasing temperature at the range of 19-31℃, developmental duration of each larvae satge of S. impressicollis was decreased, while growth rate of each larvae satge of S. impressicollis was increased. As increasing temperature survival rate of each larvae satge of S. impressicollis increased at the range of 19-28℃and survival rate of which decreased at the range of 28-31℃. while as increasing temperature survival rate of the whole larvae satge increased at the range of 19-25℃and survival rate of which decreased at the range of 25-31℃. Regression equations for the developmental duration of each larvae stage of S. impressicollis against temperature and that for the survival rate of each larvae stage of S. impressicollis against temperature were developed. The threshold temperature of development and effective accumulative temperature of generation of the larvae stage were also ascertained, which were 9.76℃and 2120.11 day-degrees by a linear regression model, 13.48℃and 1564.92 day-degrees by a direct optimization model, respectively.2. In the situation of lack of prey, the average survival time of first instar larvae of S. impressicollis, whose growth stages are Oh, 12h, 24h, 48h and 72h, are 2.77d, 3.42d, 4.47d, 5.19d and 5.48d, respectively. The higher starvation endurance ability is beneficial to the increase of survival opportunities, the increase of opportunities encountering prey as well as the control of aphid.3. The first quantitative study of environmental temperature and spatial heterogeneity effects on the predation of the adult female of S. impressicollis, The predation ratio of the adult female of S. impressicollis is the lowest at 19℃and the predation ratio at 22℃, 25℃, 28℃and 31℃are not different. Space heterogeneity has the great effects on predation of the adult female of S. impressicollis. There are mutual interference among the adult female of S. impressicollis, the intensity of scrambling competition increases with increase of its density and the searching efficiency decreases with its own density and density of prey, but predator density effects on searching efficiency larger than prey density4. In this experiment, we use HollingⅡand newⅢfitting the formula of the functional response of all stages of S. impressicollis on O. furnacalis and aphid based on the data from experiment. The results suppose that HollingⅡis better fitting the functional response that the each stage of S. impressicollis prey on O.furnaealis and aphid.5. The selective predation of the female adult of S. impressicollis to O.furnacalis and aphid was studied in laboratory. In the one-predator-two-prey system, the results showed that the adult female of S. impressieollis to O. furnacalis had positive preference and to aphid had no preference in all degrees of total prey density. In the one-predator-three-prey system, the adult female of S. impressicollis to the third instar larvae of O. furnacalis had positive preference, and to aphid had negative preference in the total density of 90. The total amount of prey and the amount of each prey captured by the female adult of S. impressicollis were simulated, and the searching efficiency of the female adult of S. impressicollis to the each prey was also analyzed.6. Spatial distribution: By estimated with the suitable degree of spatial distribution and x~2 test spatial distribution pattern of adult conformed to either the pattem of aggregation or the negative binomial distribution. It was also tested that the distributionpattern of adult were all aggregative by aggregation indexes including I-value, M~*/M -value, Ca-value, Diffusive coefficient, K-value. It was further conformed by m~*-m regression analysis law and Toylar power rule and C~*-m power rule. Meantime,the models of the oretical sampling of adult had been set up, too.
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