Thistle Tortoise Beetle Cassida rubiginosa

This beetle is a fortress wrapped in color. Its bright green, rounded shell makes it look like a tiny armored turtle, and it has defenses to match: a flexible shield protects against predator bites, while a clever protective excretion guards its eggs from harm.

Found on thistle plants across North America and Europe, it has fascinated scientists since first being documented in Quebec in 1902. Researchers are still discovering details of its life cycle—the mature larva wasn't fully described until 1931, and the instar larva wasn't recorded until 2004, showing how much even common beetles still teach us.