竹林金针虫对绿僵菌及其代谢产物的行为反应

Behavioral responses of bamboo wireworm,Melanotus cribricollis to Metarhizium pingshaense and its metabolites

绿僵菌(Metarhizium spp.)是地下害虫重要的生防真菌,为了明确绿僵菌对金针虫的驱避作用,本文以平沙绿僵菌WP08菌株为研究对象,通过Y型管等嗅觉生测方法测定了筛胸梳爪叩甲幼虫对绿僵菌分生孢子、非挥发物和挥发性物的行为反应。结果表明:金针虫的选择行为与土壤中平沙绿僵菌分生孢子浓度密切相关,当土壤中绿僵菌孢子浓度达到5×10~8个·g^(-1)干土时,绿僵菌对金针虫表现出极显著的驱避作用(P<0.001),随着浓度的降低,驱避作用减弱,当浓度达到5×10~6个·g^(-1)干土时,驱避作用消失;平沙绿僵菌孢子发酵液(浓度为1×10~8个·mL^(-1))对金针虫驱避作用极显著(P<0.001),而挥发物对金针虫驱避作用不明显(P>0.05)。本研究结果为揭示绿僵菌驱虫的内在机制提供了重要的基础信息。

Metarhizium spp. are very important entomogenous fungi for the biocontrol of soil insects. In order to clarify the repellent effect of Metarhizium spp. against wireworms,we tested the behavioral responses of Melanotus cribricollis wireworm towards the conidium,volatiles and nonvolatiles of Metarhizium pingshaense WP08 using Y-tube olfactory bioassay in the present study.The results showed that when the concentration of M. pingshaense WP08 conidium was 5 ×10^8conidia·g^（-1）dry soil,wireworms were repellent significantly by the conidium（ P〈0.001）,and the repellency was weakened with the decrease of conidium concentration in the soil. There was no repellency against the wireworms when the conidium concentration was 5×10^6conidia·g^（-1）dry soil. The fermentation broth of M. pingshaense WP08 conidium（ 1 ×10^8conidia·mL^（-1）） showed significant repellency against the wireworms（ P〈0.001）,while the VOCs emitted from M. pingshaense showed no significant repellency against wireworms（ P〉0.05）. Our results provide important basic information of chemical mechanism of fungi-repellency against insects.