Monday, September 14, 2009

A stinger and a looker

A recent foray to southernmost Ohio resulted in many nice finds of both animal and vegetable matter. Two organisms that fall in the former category are detailed below.

Impossibly cute, as caterpillars go, is the Saddleback Caterpillar, Acharia stimulea. Looking like a tiny sea slug draped in a lime-green horse blanket, the little beasts march about the foliage boldly, even in broad daylight.

You see, they have an effective defense, and know it. All of those columns of bristles may look cool, but this is heavy artillery. The bristles are called urticating hairs (Urtica = a genus of stinging nettle), and they pack a whallop. Handle one of these things and you'll get a big dose of experiential learning that'll probably stick - you won't grab another one. Should you suffer this fate, it is allegedly a good idea to find some sticky tape and plaster it over the stinging hairs that are lodged within your flesh. Then rip the tape off and with it perhaps the hairs. The tape-ripping process will hurt, too.

Anyway you slice it, this little 2 cm bag of colorful goo will cause pain should you molest it.

We were very excited to find this orange and black beauty. It's a long-horned beetle, but we all were flummoxed by its identity. And I was with some people that have long explored the haunts that we were in, and only one of us had ever seen one and then only once, but had not figured out what it was.

Searching my guides yielded no good answer, so finally in desperation I tossed a photo out to the boys on Bug Guide.net. The answer came back quickly - we had found a beautiful specimen of the Amorpha Borer, Megacyllene decora. The specific epithet, decora, means showy and the moniker is well deserved.

The borer was feeding on the nectar of Late-flowering Thoroughwort, Eupatorium serotinum. I have always thought of this native plant is rather coarse and weedy, but have revised my opinion. It formed a large stand on the banks of the Ohio River, which is where we found the beetle, and the collective blossoms emitted a pleasant, sweet-smelling aroma. The odor must be a good lure, because the patch was lousy with bugs drawn in by the fragrance.

The first part of the common name of this borer, Amorpha, refers to its host plant, False Indigo, Amorpha fruticosa. This woody shrub reaches its northern limits in Ohio, and is thought to only be native along the banks of the Ohio in our state. Populations to the north of that mighty stream are non-native, spread from cultivation or otherwise introduced.

So it makes sense that the beetle would occur where we found it. But I wonder how rare it might be, as it seems hardly anyone has seen one, at least in these parts. It may be that their span as an adult is a short one, and the window is short to go out and find one. Or perhaps they truly are rare here, scattered populations at their northernmost outposts, living where the scattered patches of indigo grow.

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6 comments:

Jared said...

Really cool Saddleback...and the beetle is neat, too! I've been finding some cool caterpillars myself, but this Saddleback is really a show-stopper.

Jack and Brenda said...

A couple really good finds. Thanks for the information.

dAwN said...

Oh my! Love that saddleback!
I have internet after two weeks without it!!! So nice to visit your blog again!
Have you seen this?
http://www.telegraph.co.uk/news/picturegalleries/howaboutthat/6167314/11-year-old-boy-finds-pink-grasshopper.html
competition for your pinky!

Coleoptera said...

Hi! Small correction to your borer article. The other Megacyllene species that you collected on your Amorpha excusion is Megacyllene robiniae, the locust borer.

You were super close; Megacyllene caryae looks nearly identical to M. robiniae, with a few obscure morphological differences. The give-away is that M. caryae is active in the spring (late March) and M. robiniae is active in the late summer/fall.

M. decora is a terrific beetle! Great find!

Coleoptera said...

Nice find! M. decora is a fantastic beetle.

I have one small correction. The other Megacyllene species that you found is actually M. robiniae, not M. caryae. They look almost identical, except for some differences with the overall form, the coloration, and the length/color of the antennae of males. The dead give away is that M. caryae is active from late March until early June, and M. robiniae is active in August/September.

Happy hunting! Just about a month until beetles start hopping around!

Jim McCormac said...

Hi Coleoptera,

Thanks for the comments but I'm confused. I don't think I mentioned any other Megacyllene in this post.

I've made posts about both M. robiniae and M. caryae in the past, and am aware of their differences, but didn't see where I alluded to either in this post...

M. decora, of course, was the topic and is far rarer than those two in these parts...