Fate of ingested iridoid glycosides in lepidopteran herbivores

Thin-layer chromatography was used to follow the fates of iridoid glycosides ingested by four species of lepidopteran herbivores. These four species differed in their feeding strategy, ranging from generalist to monophagous specialist; and in their predator avoidance strategy, ranging from cryptic and palatable to aposematic and unpalatable. The fates of the iridoid glycosides ranged from sequestration by the unpalatable specialist,Euphydryas phaeton (Nymphalidae); to passage into the hemolymph and eventual elimination in the meconium by the specialistsJunonia coenia (Nymphalidae) andCeratomia catalpas (Sphingidae); to elimination of the intact compounds in the feces of the generalist feeder,Lymantria dispar (Lymantriidae).