Becker N, Zgomba M, Petric D, Beck M, Ludwig M
German Mosquito Control Association (KABS), Waldsee, Germany.
J Am Mosq Control Assoc. 1995 Sep;11(3):329-34.
The influence of larval cadavers of Culex pipiens on recycling processes of Bacillus sphaericus was investigated by bioassays and spore counts in the laboratory. Studies conducted with 3 different B. sphaericus concentrations (0.005, 0.01, 0.05 mg B. sphaericus/liter) indicated that the presence of cadavers in the water contributed to the maintenance of toxic levels of B. sphaericus. Larval cadavers seem to contain all the nutrients necessary both for vegetative multiplication and for toxin synthesis associated with the sporulation process. Bioassays of B. sphaericus revealed that the mortality of Culex pipiens remained on a high level over a period of 26 days when larval cadavers were added every second day to the test vessels. This result was supported by a sharp increase in spore density when cadavers were added at the same interval. The test series showed B. sphaericus recycles in intact cadavers of Culex pipiens, whereas this phenomenon could not be observed when crushed cadavers were used in the trials. Therefore, our results demonstrated that for successful recycling processes it seems of crucial importance that infected cadavers remain intact at least for a certain time and also that the dosage of the applied B. sphaericus plays a major role in recycling processes whereas larval density is only of minor importance to these processes.
通过实验室中的生物测定和孢子计数，研究了致倦库蚊幼虫尸体对球形芽孢杆菌循环过程的影响。对3种不同浓度（0.005、0.01、0.05毫克球形芽孢杆菌/升）的球形芽孢杆菌进行的研究表明，水中存在尸体有助于维持球形芽孢杆菌的毒性水平。幼虫尸体似乎含有营养繁殖以及与孢子形成过程相关的毒素合成所需的所有营养物质。球形芽孢杆菌的生物测定显示，当每隔一天向试验容器中添加幼虫尸体时，致倦库蚊的死亡率在26天内一直保持在较高水平。当以相同间隔添加尸体时，孢子密度急剧增加，这一结果得到了证实。试验系列表明，球形芽孢杆菌在致倦库蚊完整的尸体中循环，而在试验中使用碾碎的尸体时则未观察到这种现象。因此，我们的结果表明，对于成功的循环过程来说，受感染的尸体至少在一定时间内保持完整似乎至关重要，而且所施用的球形芽孢杆菌的剂量在循环过程中起主要作用，而幼虫密度对这些过程的重要性较小。
