Cobalt Milkweed Beetle

Natural Habitat

Found in western North America in meadows, gardens, and hillsides where milkweed or dogbane is present.

Diet & Feeding

Herbivorous. Adults and larvae feed on the foliage and sap of Milkweed (Asclepias species) and Dogbane (Apocynum species).

Behavior Patterns

Active during daylight hours in late spring and summer. These beetles practice 'reflex bleeding' where they secrete foul-tasting compounds from their joints when threatened. They are known for their striking metallic blue or teal iridescence.

Risks & Benefits

Harmless to humans; they do not bite or sting. In the ecosystem, they serve as a food source for some predators, though they are often avoided due to their chemical defenses derived from the toxic plants they eat.

Identified on: 3/11/2026