April, 2007

Fiery Searcher

Our featured beast this month is the beautiful fiery searcher (Calosoma scrutator). This ground beetle is also called the caterpillar hunter, which aptly describes its dietary preferences. Many ground beetles are small and dark colored, but the fiery searcher is a metallic rainbow. With green elytra (wing coverings), a blue pronotum (the area that connects the head and the body) ringed with red, and purple legs, this insect cannot be mistaken for any other. The underside, though rarely seen, sports orange and green stripes and blue spots, all equally metallic. Its large size, about 1 inch long, and quick movements make it easy to spot, if one can be found during the day. In common with many other ground beetles, this predator is nocturnal.

Although most ground beetles are found where you would expect, i.e. on the ground, some species do climb trees. The fiery searcher is one that does this, as its main prey, caterpillars, are found high up in the branches. This beetle is considered beneficial, but it is not harmless. The same jaws that can tear apart a caterpillar can also deliver a painful bite if the insect is handled. The caterpillar hunter has another, even better defense, though. I found one of these beetles walking on a sidewalk next to a shopping center several years ago. It had probably been lured at night by the lights. Thinking it might get stepped on, I picked it up and moved it to some shrubs nearby. I could feel it spray something on my hand and the next thing I knew, my fingers smelled TERRIBLE, with a very nauseating odor. Like many ground beetles, including the bombardier beetles famous for their chemical gas protection, the fiery searcher has a noxious spray to deter predators.