These gorgeous caterpillars were discovered during the Creative Creatures camp with the Montana Natural History Center. They all sport a “horn,” but look different depending on what stage they are in. Young larvae are variously patterned with green, yellow, and black; older larvae have a distinctive red, black, and yellow pattern with a double row of white spots on each side and white speckles. In any stage, they are a welcome sight. They are a non-native species that’s been released in the fight against leafy spurge. They can be found in several western states (MT, ID, and OR) as well as eastward to at least Michigan. Their range continues to grow. There can be one to two generations a year.
Size: Mature larvae may approach 10 cm. in length
Photos by: Carolyn Taber on 7/13/22 near Clinton, MT