关键词: 后斑小瓢虫, 竹茎扁蚜, 捕食功能, 控害潜能, 生物防治

Abstract: [Objective] In order to understand the potential control capacity of Scymnus (Pullus) posticalis against Pseudoregma bambusicola, the optimum predator density, the maximum predatory amount, interference coefficient, instantaneous attack rate and treating time of S. (P.) posticalis fed on Pseudoregma bambusicola were studied. By measuring the life table of S. (P.) posticalis, I investigated the population growth trend of S. (P.) posticalis after feeding with P. bambusicola, to provide a scientific basis for utilizing S. (P.) posticalis to control P. bambusicola. [Method] Under laboratory conditions (temperature (23±1)℃, relative humidity (70%-73%), feeding with fixed time and fixed quantity in plastic cases was conducted to observe and measure the predation of S. (P.) posticalis on P. bambusicola, and to test S. (P.) posticalis's interference effect of its own density. With the application of Data Processing System, I used methods of insect ecology, such as the model of Holling-Ⅱ, the new model of Holling-Ⅲ functional response developed by Wang Shize, and statistic model of functional response of predator to prey developed by Jin Kaizheng, for matching. Furthermore, I analyzed parameters of the optimum predator density, the maximum predatory amount, inference factor, instantaneous attack rate and treating time of P. bambusicola being preyed by S. (P.) posticalis, for studying the regulating effect of S. (P.) posticalis on P. bambusicola. I also used the rearing method of setting veil screen in the forest to measure the life table of experimented S. (P.) posticalis, in order to study S. (P.) posticalis's quantitative characteristic of inner increase capacity. [Result] Under the controlled conditions, the predatory function responses showed that the average predation was able to amount 75 max per day for the 3^rd instar S. (P.) posticalis on P. bambusicola, and 81 max per day for adult S. (P.) posticalis, both the 3^rd instar and adult S. (P.) posticalis were strong predators of P. bambusicola. The interference effect test on S. (P.) posticalis's density showed that the pest control capacity of S. (P.) posticalis could reach the maximum when the release ratio was 1∶38.8; and the parametric measure result of life table showed that the survival rate of indoor rearing female imagoes was able to reach 63%, and after a generation, the population increased by 85.3638 times. Meanwhile, within the test temperature range, when the reproductive rate (λ) was larger than 1, the population of lab reared S. (P.) posticalis increased in a geometric ratio. By comparing the parameters on life tables, and analyzing the models of functional response, it was shown that S. (P.) posticalis was a strong predator of P. bambusicola, and it had strong reproductive ability, and S. (P.) posticalis had strong pest control capacity against the population of P. bambusicola. [Conclusion] This study indicated that the population of S. (P.) posticalis fed with P. bambusicola grew exponentially, and it had a great potential of preventing and controlling P. bambusicola.

Key words: Scymnus (Pullus) posticalis, Pseudoregma bambusicola, predatory function, control potential, biological control