Pest ControlWhat's This Bug?

What’s This Bug? The Fiery Searcher Beetle

Brought to you by ARBICO Organics

This beautiful beetle is the Calosoma scrutator, commonly known as the Fiery Searcher or simply Caterpillar Hunter. As their name(s) suggests, these beetles are tireless and aggressive predators. Luckily for us humans, the foods they love best are some of the most crop-damaging pests. They will prey upon a variety of insects in varying life stages, although their favorite is the caterpillar stage. Their dinner of choice depends on whether they are larvae or adults, as they hunt in both stages. Fiery Searcher larvae, since they are not as agile as the adults, prefer to target insects in their pupal stages while adults are way less picky (here’s more on their feeding preferences). According to this article, they favor the all-star list of crop pests which includes the larvae of imported cabbage worms and gypsy moths, the larvae, pupae and eggs of root maggots, as well as the Colorado potato beetle, diamondback moths, cutworm and cabbage loopers, aphids, asparagus beetles, slugs and flea beetles. Some species even eat snails. Fiery Searchers are exceptionally long-lived for an insect; they can live 2 years or more. And during their lives they can consume hundreds of insects. So, these are clearly helpers that you want to have in your yard and garden.

Fiery Searcher Larva (R) eating Pipevine Swallowtail larva.

These beetles live throughout North America, but their numbers are largest in eastern states. They are nocturnal, so even if you live in an area where they are prolific you may not see them. They spend their daylight hours in crevices, under leaf litter, logs and rocks and venture out in the dark. This nightlife suits them well; it allows them to stay hidden from those animals that like to prey on them and the insects that they like to eat are also hiding in daylight for the same reasons. As pests come out at night with a false sense of security and their eyes on your plants, the fiery searchers are ready to snatch them up.

Fiery searchers are usually found in fields and gardens, although some live on forest floors. These beetles have wings, but rarely fly. Instead, they use their long legs to scamper up branches and tree trunks to grab a meal. They are especially fond of tent caterpillars and gypsy moth larvae, which they find up in the trees. Fiery searchers don’t just use their long legs to climb trees, their legs allow them to run very fast to chase down prey. Their burst of speed in pursuit of prey is similar to a cheetah, so much so that they have been called the cheetah of the insect world.

If you come across a fiery searcher, it is best to give it a wide berth. These are large insects (about 1-1½ inches) with big, sickle-shaped mandibles. They will not hesitate to give a nasty bite if you mess with them. And if that doesn’t do the trick, they can and will emit a foul odor when handled. Clearly, they have some tools that help them be the predator and not prey.

Fiery searchers are around from May through November but are most active from May through June when trees have leafed out and caterpillar populations boom. In the fall, they will be scuttling around getting the last of the bug goodies before it gets too cold and it’s time to overwinter. They like to spend their winters under some bark or under a rock.

These beetles are glorious – not just in how pretty they are, but in their hunting game. They literally take no prisoners. Here’s an informative video that shows them in action and this article contains three separate short illustrative videos. Enjoy the glory that is the fiery searcher on the hunt.

 Pam Couture is the Lead Content Writer at ARBICO Organics. She lives in Tucson, Arizona, where she is surrounded by family, friends, and nature.

ARBICO Organics can be contacted at 800.827.2847 and you can visit their website at

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