Defensive secretions in three ground-beetle species (Insecta: Coleoptera: Carabidae)

Abstract

The adults of three ground-beetle species were induced to discharge defensive secretions into vials. The secretions were obtained by CH2C12 extraction. Altogether 11 compounds were identified by GC-MS analysis. Calosoma sycophanta possesses 10 defensive compounds, Carabus ullrichii seven, while Abax parallelepipedus has six compounds. Methacrylic, tiglic and isobutyric acids were present in all samples. The first two organic compounds were predominant in the extracts of Abax parallelepipedus. Methacrylic acid and salicylaldehyde were the major compounds in extracts of Calosoma sycophanta. Methacrylic and angelic acids were the major components in extracts of Carabus ullrichii. Propanoic acid was detected for the first time in the family Carabidae and in all animals. 2-Methyl butyric, angelic and benzoic acids were found for the first time in the subfamily Carabinae. Our finding of butyric acid is its first precise identification in the Carabinae subfamily. 2-Methyl butyric, angelic, crotonic, senecioic and benzoic acids were found for the first time in a European groundbeetle species. The compounds detected in the defensive secretions serve as protection against predators.