Lucanus capreolus

Reddish-brown stag beetle
Lucanus capreolus

Here’s a big little beast. This reddish-brown stag beetle is about an inch long, with a thick, deep red body and huge mandibles. They look like an over-grown, over-armored army ant, but in fact the jaws are not terribly powerful. (From what I hear — I haven’t been pinched by one personally.) The beetle doesn’t need them to be: the adults feed on tree sap, and the females have little nubbins instead. Well, really the females have normally-proportioned mandibles for a beetle of their quite large size, but in comparison to the males’, they look a bit dwarfish.

Given that these oversized mandibles are useless for foraging and impractical for defense, and that it’s the males who lug them around, you can immediately guess what they’re for: wrestling. They fight over breeding territory, and the biggest mandibles gets the ladies. After mating, the female lays her eggs in rotten wood, which feeds the larvae as they grow over the next few years.

I found this particular guy upside-down on the sidewalk, fairly early in the morning. They’re crepuscular animals, meaning they come out at dawn and dusk, so he was probably wrapping up his morning activity. No idea how he got flipped over, but they’re not very graceful fliers, and he may have just tired himself out. They seem to play dead when on their back, like many insects, but I wonder if that’s a defensive response or if they just take a moment to gather their strength. At any rate, I brought him home and stuck him in a clean plastic cup, with some paper towels for cover, and gave him a few drops of sugar water later on.

To shoot him, I turned a small cardboard shipping box into a lightbox, by cutting away a few extra sides and flaps, taping white printer paper along the inside, and covering the top with Rosco 1/4 Tough diffusion paper. I put the 430EX II on a light stand directly overhead, and used the WhiBal to nail the color temperature down and get the exposure in the right ballpark. I took a few shots at 1:1 with the 100mm Macro, and made a series of four verticals to merge into a hi-res horizontal, but he moved around a bit as I was shooting and they don’t have a consistent focal point. This is one of them.

Identification was simple. Any huge beetle with huge mandibles is probably one of the stag beetles (Lucanidae), and we only have a few in New England. Lucanus capreolus is dark red, with a lighter yellow thigh. I was pretty confidant after flipping through Marshall’s guide, and then checked the key on bugguide.net to confirm it. There’s another species, L. elaphus, with even larger mandibles, but the ones on this guy are only about as long as the pronotum (the head). It’s not visible in this image, but he has fan-shaped clubs at the end of the antennae, the eyes are slightly divided by a little protrusion called a canthus, and the surface of the pronotum and the elytra (the wing covers) are pretty smooth. All these things say Lucanus, and rule out other related stag beetles.