“My daughter found this insect in the bathroom, and I haven’t been able to stop thinking about it since. I’m trying to figure out what it is, whether it’s dangerous, and what you should do if you find one in your home.”

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What exactly is a cockchafer?

The cockchafer (Melolontha melolontha, if we’re being scientific) is a chunky, scarab-like beetle that usually appears in late spring across Europe, mainly in May and sometimes into June—hence the name “May beetle.” It grows to about 2–3 cm (0.8–1.2 inches) long, which doesn’t sound very big until it’s buzzing right past your face. Males have distinctive fan-shaped antennae that look like tiny satellite dishes. They use them to detect females. Very sophisticated.

Its flying style? Imagine a wind-up toy trying to navigate through a hurricane. It doesn’t really fly so much as lurch from one surface to another with alarming confidence and almost no coordination.

How can you tell it’s a cockchafer?

If you spot a large beetle-like insect bothering your plants in May, there’s a good chance it’s a cockchafer. Here are the main identifying features:

• Color: Reddish-brown wing covers with a dark, almost black underside.
• Antennae: Large, fan-shaped antennae on males, making them look like they’re dressed for a masquerade.
• Size: Larger than the average beetle—not horror-movie huge, but definitely big enough to ruin your evening.
• Markings: Small white tufts or patches along the sides of the abdomen that look like bits of lint stuck to its shell.
• Behavior: Loud, clumsy, very active at dusk, and irresistibly attracted to lights.

Also, if you’re in Europe and it’s spring, it’s likely a cockchafer. In North America, the name “May beetle” is commonly used for a different but closely related beetle species. They behave similarly, but they’re not the same species.