CHEMICAL ECOLOGY OF INSECT DEFENSE CHEMICALS AGAINST ENVIRONMENTAL MICROORGANISMS

本研究表明，在62种已报道的昆虫防御物质中，有32种对7种常见真菌有或多或少的抑制作用。其中对凤蝶幼虫的防御物质马兜铃酸和对拟步甲和步甲的苯醌类化合物的活性最高，而脂肪族化合物大多没有活性或活性较低。另外，还观察到具有防御性分泌物的瓢虫Rodolia limbata幼虫的有机溶剂提取物对这些真菌的生长具有抑制作用。但对麻点芋螺、家蝇和毛雀鲷幼虫提取物的抑菌活性不明显，其防御分泌物的抑菌活性尚不清楚。但这三种昆虫的正己烷提取物对6种供试真菌的活性较弱，这表明这三种昆虫体内可能也含有一些防御真菌侵袭的化学物质，这些结果强烈提示昆虫防御化学物质可能对环境微生物作为昆虫的天敌具有有效的抵抗作用。

This work showd that of 62 chemicals which have been reported as insect defense substances, 32 chemicals have more and less antifungal activites agaist 7 species of common fungi which were cultured in an agar medium. The most effective chemicals were aristrochic acid as defense substance of swallowtail butterfly larvae and benzoquinones of tenebrionid or carabid beetles, but most of aliphatic hydrocarbones were not or less active. And also larvral extracts with organic solvents of a lady bug, Rodolia limbata which have defensive secretions against their predetory enemies, were observed to inhibit growth of these fungi. But no prominent antifungal activies were found in larval extracts of Conogethes punctiferalis, Musca domestica and Pascothea hiralis, which have not been known their defensive secretions. However, hexane extracts of these three insects were slightly active agaist 6 species of fungi tested, suggesting a possibility that these insects also have some chemical agents for defensing fungal attack.These results were strongly suggestive in that insect defense chemicals may be effective agaist environmental microorganisms as a natural enemy of insects.