Cardiac Glycosides in the Defensive Secretion of Chrysomelid Beetles: Evidence for Their Production by the Insects

The defensive secretions of some chrysomelid beetles belonging to the genera Chrysolina , Chrysochloa , and Dlochrysa contain complex mixtures of cardenolides. The spectral data for some of these compounds suggest that they are monohydroxylated digitoxigenin derivatives linked to a pentose (such as xylose or arabinose). Evidence indicates that the beetles do not sequester these steroid glycosides from their host plants.