Feeding specialization and host-derived chemical defense in Chrysomeline leaf beetles did not lead to an evolutionary dead end

Combination of molecular phylogenetic: analyses of Chrysomelina beetles and chemical data of their defensive secretions indicate that two lineages ind ependently developed, from an ancestral autogenous metabolism, an energetic ally efficient strategy that made the insect tightly dependent on the chemi stry of the host plant. However, a lineage (the interrupta group) escaped t his subordination through the development of a yet more derived mixed metab olism potentially compatible with a large number of new host-plant associat ions. Hence, these analyses on leaf beetles document a mechanism that can e xplain why high levels of specialization do not necessarily lead to "evolut ionary dead ends."