著者

兼久 勝夫

出版者

岡山大学資源生物科学研究所

雑誌

岡山大学資源生物科学研究所報告 (ISSN:0916930X)

巻号頁・発行日

vol.4, no.1, pp.9-23, 1996

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The secretion of defensive substances by more than 250 species of carabid and brachinid beetles was investigated, and discussed from a phylogenetical viewpoint. The morphological of secretion glands and secreted components were identified in the genus level. Specific subgenus and species had peculiar characteristics. The pair of defensive organs consisted of many small synthetic lobes, large reservoirs, collecting ducts from lobes to reservoirs and secretion ducts from reservoirs. The pair dust opened at the last sternal intersegmental membrane. There was species specificity in the reservoir shape, synthetic lobe shape and entering site of the collecting ducts into reservoirs. The spherical shape lobes produced short chain fatty acids, the elongated shape lobes produced m-cresol and the thick board shape lobes produced benzoquinones. Two types of fatty acid-secreting beetles were found, one secreted formic acid, and the other mixed short chain fatty acids. These short chain fatty acids were metabolized from some amino acids, methacrylic acid was from valine; tiglic acid, α-ethyacrylic acid and angelic acid were from isoleucine; senecioic acid was from leucine and crotonic acid was from lysine. These unasaturated acids were sometimes detected with a trace amount of corresponding saturated acids. A few species secreted larger amounts of saturated acids with a trace amounts of unsaturated acids. Fatty acid composition was generally genus-specific. In a few cases, however, species-specific acid composition was also observed. m-Cresol-secreting beetles were observed only in Panagaeni and Chlaeniini except subgenus Chlaenius Chlaeniini except subgenus Chlaenius Chlaeniellus beetle. 1,4-Benzoquinone and 2-methyl-1,4-benzoquinone-secreting beetles were observed in subgenus C. Chlaeniellus. This beetle secreted these substances at body temperature from a reservoir with no sound. Brachinidae beetles, called bombardier beetles, have a pair of brownish reaction chamber connected with a reservoir. They sprayed the two benzoquinones at about 100℃ making sound.オサムシ科とクビボソゴミムシ科の防御物質の分泌について系統分類学の視点から250種以上を調べた。属レベル共通性が見られたが、中には亜属や種での特異性のある成分が検出された。防御物質の分泌に関する器官は左右一対の多数の小型の生合成器官、大きな貯蔵囊、それをつなぐ輸送管と末端環節間膜に開孔する分泌管より構成されていた。体の大小、管の嵌入場所や貯蔵囊の形などで、種による特徴があったが、生合成器官の形に相応して生成物質に特徴があった。すなわち、球形器官は短鎖有機酸を、紐状器官はメタクレゾールを、板状器官はベンゾキノンを生成した。有紀酸の分泌種としてはギ酸分泌種があり、この類にあっては副成分として2トリデカノンを含む類とエステルを含む類があった。オサムシ族、ナガゴミムシ族その他かなり多くの種類は分岐アミノ酸であるバリン、イソロイシンとロイシンやリジンから生成されるメタアクリル酸、チグリン酸、エチルアクリル酸、セネシオ酸やクロトン酸と各々の飽和酸の幾つかを構成成分としていた。一般的に属レベルで同じ成分が多かったが、例外的に種の特異性成分もあった。メタクレゾールはキベリアオゴミムシ亜属を例外とするアオゴミムシ類とヨツボシゴミムシ類で検出された。ベンゾキノン類はキベリアオゴミムシ亜属が分泌し、亜属で特徴を示した。この類は貯蔵囊のみからの体温での分泌であった。クビボソゴミムシ科もキベリアオゴミムシ類と同じ組成のベンゾキノンを分泌するが、貯蔵囊に接して茶褐色をした酸化反応室を有し約100℃の高温噴射を爆発音と共に行った。