Semiochemicals derived from pyrrolizidine alkaloids in male ithomiine butterflies (Lepidoptera: Nymphalidae: Ithomiinae)

Analysis of male hairpencil components of 54 species in 30 genera of Ithomiinae, butterflies showed the presence of 13 volatile compounds formed by hydrolysis, oxidation, lactonization and/or methylation of both necic acid and pyrrolizidine base portions of lycopsamine, an alkaloid widespread in nature and known to be specifically sought, ingested and stored by these insects. Six of these compounds have not been reported before from insects. Comparison of occurrence of components with proposed phylogenies of the 50 or more genera in the subfamily did not give clear patterns, though simpler derivatives well known in other Lepidoptera occurred throughout the subfamily, while more specific structures, including a lactone resulting from specific oxidation of an unactivated methyl group, were more typical of apomorphic genera. (C) 2004 Elsevier Ltd. All rights reserved.