Thaumetopoea-processionea
Guides
Calosoma sycophanta
forest caterpillar hunter, Agreeable Caterpillar Hunter
Calosoma sycophanta is a large, metallic ground beetle renowned for its specialized predation on caterpillars. Adults reach 21–35 mm in length and display striking iridescent green elytra with a bluish scutellum, though coloration shifts with light angle to show blue, bronze, copper, gold, or black tones. Both adults and larvae are arboreal hunters, ascending trees to prey on caterpillars including Lymantria dispar (gypsy moth), Thaumetopoea processionea (oak processionary), and Thaumetopoea pityocampa. The species is diurnal and visually orients toward dark objects and tree bases in forests. Native to Europe, it has been introduced to North America for biological control and is now established in the northeastern United States.