Megachile pugnata, commonly known as the pugnacious leafcutter bee, is a species of solitary bee belonging to the Megachilidae family. It is found in various regions of North America. These bees are known for their aggressive behavior and distinctive leaf-cutting habits, where they use their strong mandibles to cut circular pieces of leaves for constructing their nests. They are important pollinators, particularly for plants in the Asteraceae family.