Good Bugs: Calosoma Scrutator

About five years ago, Romie walked into the house one evening and brought in a hitchhiker. He wasn't aware of it, but there was a menacing-looking beetle hanging out on his shoulder. It takes a lot to rattle him, but this particular beetle elicited an excited response from him. Yeah, excited. That's it.

We corralled that beetle long enough for me to look closer and look it up. We found that it was a Calosoma scrutator, more commonly known as "caterpillar hunter" or "fiery searcher." This past weekend, he found another one - only the second time we've ever seen one - clinging to the floating chlorinator in our pool. The man is a beetle magnet.

I grabbed the beetle so that I could get a good photo of it. As I was carrying it into the house, it not only bit me with its pincers (mildly uncomfortable), it emitted a really unpleasant odor all over my hand. It was every bit as offensive as the one that those annoying lady Asian beetles give off.

Calosoma scrutator

Calosoma scrutator is one of the largest ground beetles and is native to southern Canada and the US. They're most active during the months of May through November, but are more likely to be seen in May, as trees leaf out and caterpillars are munching on the new growth. They are known to climb trees in search of their prey. Caterpillars are their favorite food and this qualifies the C. scrutator as a beneficial insect.

These big boys are quite alarming when you first see them. They typically measure 1-1½ inches in length and an inch wide. And while you might think they'd be slower than most insects, they move very fast! The only way I could get a good photo was to contain it in the bottom of a drinking glass.

Adults can live for as long as three years and they're ground dwellers. Don't be alarmed if you see one. Count yourself as lucky!