Anthraquinone
Guides
Trirhabda geminata
Encelia Leaf Beetle
Trirhabda geminata is a skeletonizing leaf beetle in the family Chrysomelidae, commonly known as the Encelia leaf beetle. It is a specialist herbivore strongly associated with brittlebush (Encelia farinosa) and related Encelia species in the Asteraceae. The beetle is univoltine, with adults emerging in spring to feed, mate, and oviposit on host foliage. Larvae feed gregariously on leaves, passing through three instars before pupating in soil. The species is notable for accumulating hydroxylated anthraquinones (chrysophanol and chrysazin) through apparent de novo biosynthesis, as these compounds are absent from its host plant and retained rather than excreted.