Fiery Hunter Beetle

2014 April 19

Sandy was digging a post-hole in the yard on June 29, 2013, and Sam happened to notice this fine, large beetle falling into the hole.

It is clearly predatory. Those mandibles are obviously best suited for, say, dicing caterpillars and slugs into bite-sized chunks.

A bit oddly, the beetle didn’t seem to inclined to use those mandibles for defense. It made threatening poses, but didn’t seriously try to bite me.

As it happens, this is probably the same kind of beetle as one I posted way back in May 2007. The thing is, there has evidently been a name change since then. At the time, it was Calosoma calidum, but the current name on BugGuide is Callisthenes calidus. I had thought it might also be the Black Caterpillar Hunter, Calosoma Sayi, but the pronotum (the segment right behind the head) is a slightly different shape.

These beetles have strong legs, and a body shape that lets them squeeze under things to go after their preferred prey (mostly slugs, caterpillars, and worms). These beetles are therefore quite useful to have around in the garden if you have slug or cutworm problems.

The wing cover spots are quite striking, and are also variable in color. The one I caught in 2007 had gold spots, while this one has bright red spots. One would think that the color variation would indicate two different species, but apparently not.

Anyway, we see these around here in Houghton with fair frequency, but I don’t recall ever seeing any in southern Michigan when I was a kid. I guess the local environment is just more congenial to them up here.

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