Identification of warning odour components, bitter principles and antifeedants in an aposematic beetle: Metriorrhynchus rhipidius (Coleoptera: Lycidae)

Abstract

2-Methoxy-3-isopropylpyrazine was identified as the most characteristic odor component of M. rhipidius (Macleay), higher and lower homologs of this compound, cineole and a series of n-alkanals are also present. 3-Phenylpropanamide and 1-methyl-2-quinolone are the major bitter principles of the hemolymph and series of highly unsaturated, acetylenic acids and their glycerides are also present. The roles of these substances in the biology of the species and their bearing on possible odor-based Muellerian mimicry are discussed.