The host specificity of phytophagous beetles (by the aid of Cucurbitaceae-feeding beetles

葫芦科取食甲虫的寄主特异性可以用寄主植物中葫芦素的存在来解释。研究了以葫芦科植物为食的海绒螯虾（Epilachna admirabilis）、黄绒螯虾（Aulacophora femoralls）、黑绒螯虾（A.nigripennis）和绿绒螯虾（a.l lewisii）的取食刺激物。葫芦素能刺激前3种植物进食，而葫芦素不能。从一种海绵葫芦中分离出一种摄食刺激物，路易丝虫病菌以其为食。一种分离的化合物是一种类固醇。该化合物不作为一种喂养刺激物对E。这种化合物是路易丝瓜以海绵葫芦为食的关键物质。Trichosanthes kirilowii Maxim。变种日本人更倾向于以鱼为食。但该植物不含葫芦素。饲喂性兴奋剂鉴定为甾体类，2a -二乙基5 - a胆碱-7、22e -二烯3 β-醇和木犀草素-7-o-葡萄糖苷。摄食刺激活性因物种而异。上述结果表明，这些物质是3种昆虫取食姬斑蝽时的关键物质。其主要寄主植物为绞股蓝。从葡萄属植物中分离得到一种促食剂，经鉴定为三萜葡萄糖苷。据认为，许多植食性昆虫不受寄主植物中特定物质的刺激而取食。这一调查可能揭示植虫以不含特定物质的寄主植物为食时使用了什么样的物质。

The host specificity of Cucurbitaceae-feeding beetles is explained by the existence of cucurbitacin in the host plants. The author investigates the feeding stimulants of Epilachna admirabilis, Aulacophora femoralls, A.nigripennis and A.lewisii which feed on Cucurbitaceae. The former 3 species are stimulated to feed by cucurbitacin, but the latter is not. A feeding stimulant was isolated from a sponge gourd which A.lewisii preferably feeds on. A isolated compound was a kind of steroids. This compound did not act as a feeding stimulant to E..adomirabilis, A.femoralis and A.nigirpennis This compound is a key substance when A.lewisii feeds on a sponge gourd. Trichosanthes kirilowii Maxim. var.japonicapreferably feeds on by. E.admirabilis A.femoralis and A.ninigripennis, but this plant dose not contain cucurbitacines. Feeding stimulants were identified them as a kind of steroids, 2A-diethyl 5 a cholesta-7,22E-dien 3 β-ol and luteolin-7-o-glucoside. Feeding stimulative activity was different from species specify. These results indicate that these substances are key substances when 3 species feed on T.kirilowii Maxim var.japonica. The main host plant of Paridea angulicollis is Gynostema pentaphyllum. A feeding stimulant was isolated from G.pentaphyllum, and was estimated as a kind of triterpenoid glucoside. It is thought that many phytophagous insects are not stimulated to feed by specific substances in the host plants. This investigation may reveale that what kind of substances are used when phytophgous insects feed on host plants not contained specific substances.