Abstract: 　Objective To explore possible physiological and biochemical mechanisms of Lagenidium giganteum infection in killing mosquito larvae. Methods The content of lipid and the activities of esterase and lipase between the normal and infected mosquito larvae were observed with histochemical method. The results were photomicrographed and analysed by image analysis using computer. Results In 24 hrs after infection, the content of lipid in the infected Culex quinquefasciatus larvae was lower while the activities of esterase and lipase in the larvae were higher than the control. In 48 hrs and 78 hrs after infection, the content of lipid in the infected larvae of C. quinquefasciatus and Ae. albopictus were significantly lower while the activities of esterase and lipase were significantly higher than those of control. Conclusion The content of lipid in the mosquito larvae decreased while the activities of esterase and lipase increased after the infection of Lagenidium giganteum . The disorder of lipid metabolism might be part of the killing mechanisms to C. quinquefasciatus and Ae. albopictus larvae.

Key words: Lagenidium giganteum, Culex quinquefasciatus, Aedes albopictus, Larva, Histocytochemistry