Painted Hickory Borer

It's not often that one gets a "life bug" while in their office, but it happened to me today. Colleagues at work know that I'm interested in a wide sphere of things in natural history, and routinely deliver specimens of flora and fauna, curious as to their identity. I appreciate their curiosity, because I always learn a lot from identifying mysteries, too.

I had stepped away from the office briefly, and upon returning noticed a thick glass jar sitting on my desk. "Ah, a bug of some sort!" thought I, seeing a small moving shape through the opaque glass. Unscrewing the lid brought clarity to the situation, and I quickly realized there were two gorgeous Painted Hickory Borers, Megacyllene caryae, within the jar! I'm no Eric Eaton, and the reason that I knew its identity so quickly is because this was a bug high on my most wanted list.

A type of long-horned beetle, the Painted Hickory Borer is a stunner. And a bit of a mystery. In all of my poking about I had never seen one, and the person that brought them to me had never seen them before, in ten years of living on their Knox county property. Painted Hickory Borers look nearly identical to another, apparently much more common species, which I'll get to. It seems that in most texts and references, this one is hardly mentioned and often just as a brief footnote in accounts of its more common relative.

This borer and some others of its ilk are thought to be wasp mimics, and they do look the part. When they do emerge from their woody haunts, Megacyllene borers spend time nectaring at flowers, and looking like a stinging nasty is probably a good ploy. As you have no doubt inferred from the common name, this beetle utilizes hickory trees (genus Carya) in the subadult stages.

I wonder if this is an irruptive species. In other words, many years can pass with populations remaining at very low levels, and then, for whatever reasons, the population explodes and we get a conspicuous outbreak. The finders of this specimen report that dozens were around their yard. And coincidentally, I was told of yet another large concentration of Painted Hickory borers today, near Chillicothe in Ross County.

This is the apparently much more common look-alike, the Locust Borer, Megacyllene robiniae. Note that all of the dorsal stripes are bold yellow; on the hickory borer the M-shaped stripe is whitish as are two dots on the carapace towards the rear. These don't emerge until early fall, and are quite fond of nectaring on goldenrod. I shot this one last September on Canada Goldenrod, Solidago canadensis. The host tree is Black Locust, Robinia pseudoacacia. I see scads of these every year, and once I learned about the existence of the apparently far less frequent Painted Hickory Borer, I've wanted to see one.

Finally, our third? Megacyllene borer in Ohio, and perhaps the showiest, the Amorpha Borer, Megacyllene decora. This one may actually be the rarest, but I think I know how to find them now. Some of us will be mounting an expedition this August to look specifically for this beauty; should be quite the adventure.

Keep your eyes peeled for Painted Hickory Borers, and let me know if you find any. Or, if you know any interesting info about them, I'd appreciate hearing it.