Pyrrolizidine alkaloids (PAs) were analysed in 40 species (38 genera, all 14 tribes) of the butterfly subfamily Ithomiinae. The principal PAs found were the epimers lycopsamine and intermedine. These results suggest that ithomiines visit mainly PA sources containing monoester lycopsamine-type PAs, and transform various other diastereoisomers into lycopsamine and intermedine, with the 7R configuration. Other PA-types found in butterflies are probably related to the availability of PA sources. Unknown PAs ([M](+) 297), that resemble the arctiid insect-PA callimorphine, were found in small amounts in 10 species. Copyright (C) 1996 Elsevier Science Ltd243181188