CHEMISTRY OF THE SCROPHYLARIACEA .13. IRIDOID GLYCOSIDE CONTENT OF EUPHYDRYAS-ANICIA (LEPIDOPTERA, NYMPHALIDAE) AND ITS MAJOR HOSTPLANT, BESSEYA-PLANTAGINEA (SCROPHULARIACEAE), AT A HIGH-PLAINS COLORADO SITE

The checkerspot butterfly, Euphydryas anicia, utilizes mainly Besseya plantaginea and only occasionally Castilleja integra as a larval hostplant at Michigan Hill, a few kilometers from a site where C. integra is used by over 90% of the butterflies. The B. plantaginea leaves that are consumed contain 9-22% iridoid glycosides, composed mainly of catalpol and catalpol esters, while larvae from the same plants contain 6-18% iridoids, mainly catalpol and no esters. Field-collected adult butterflies contain 0.5-4.3% iridoids. Laboratory-reared adults secrete iridoids in the meconium upon eclosion and retain similar amounts. The adult and meconium iridoid content is considerably lower than in the larvae, and metabolism in the pupal stage may be occurring. © 1990 Plenum Publishing Corporation.