My wife and I were walking the dogs down our country road. Out of the corner of my eye, I noticed a dark-coloured blob slowing making its way across the pavement to the gravel shoulder. A blueish-black blob, actually. A SHINY blueish-black blob. A sluggish wasp, perhaps? No, better. BEETLES!
“AAAAH! I want them!!!”, I yelled, handing off the yellow dog and crouching down to get a closer look.
Oil beetles! A pair…heavy-bodied, short-winged and gleaming; the larger female carried the male on her back. “Why don’t I have my camera?”, I bemoaned.
I scootched them into the baseball cap I was wearing and pinched the fabric closed into a sort of bag.
“Should we head back home?”, my wife asked. “Yes please”. She wrangled all three dogs as I held my prize with both hands.
When I got in the house and peeked in my cap, they had uncoupled. Rats. So much for an arthroporn shoot. I popped them in the fridge to chill out while I got my camera and scoped out a well-lit and not-too-windy nook in the yard.
I removed my little subjects from where they sat next to the pickle jar and brought them outside. The male soon sufficiently warmed to remember what he’d been up to before I’d so rudely interrupted them, and immediately got back to business. The female did not appear too impressed, but relented to the piggy-backing.
I carefully placed them on a large wind-fallen branch and watched them for a bit as they roamed. Soon they stopped, and the male began to flirt, delicately touching the female’s head with his mouthparts and stroking her antennae with his own. One of the most remarkable things about the male oil beetle is his highly modified antennae; they have a distinct “C” of enlarged and oddly-shaped segments near the mid-point.
Modified male antennae
Occasionally he would draw her antennae into the crook of the “C”, seeming to grasp them within. On BugGuide, I saw someone refer to this action as “antennal foreplay”. I only observed this particular behaviour a handful of times, and didn’t manage to get great pictures, but here’s one that shows it well enough so you can get the idea:
Foreplay or no, his efforts apparently weren’t cutting it for the female. She soon shrugged him off and trundled off on her own. He took the hint and did the same. Since they’re flightless beetles, I used the opportunity to get a few portraits:
At one point, I must have handled the female a little too roughly, as I noticed yellow beads of oil on her leg joints and on/around her head (see image below). Oil beetles are named for this defense mechanism. Droplets of hemolymph, containing cantharidin, are extruded; cantharidin can be a serious irritant, causing blisters in some (oil beetles are also called “blister beetles”). I’ve handled beetles of this genus (Meloe) a couple of times now, with no ill effects.
Female, with oil (and a snack)
The photoshoot concluded with me getting this image of the male, which I just love. Here’s lookin’ at you, kid:
Heres lookin at you...
What an awesome start to the bug season!!!