Differences in Neutral Components of the Defensive Secretion in Formic Acid-Secreting Carabid Beetles

The neutral components of the pygidial defensive secretion in formic acid-secreting carabid beetles were identified by gas chromatography, mass spectrometry and infrared spectroscopy. Formic acid made up more than ninety-five percent of the secretion and neutral substances were minor components, less than five percent. There were two types of formic acid-secreting beetles in regard to neutral components : Platynini, Harpaline, Licinini, Lebiini and Odacanthini had 2-tridecanone, while Zuphini and Dryptini had decyl acetate, decyl formate and nonyl acetate. Component amounts differed among beetles of the same type.