Wednesday, September 25, 2013

Beautiful slugs!

Someone's finger points out a tiny slug moth caterpillar. It appears to glow, and it does. A tactic for upping the odds of finding caterpillars, especially little ones, is to use a blacklight flashlight. Many species glow quite brightly when so lit, and the searcher can spot them from afar.

From this photo, the uninitiated could be forgiven for thinking that slug caterpillars are nothing. Inconsequential little specks hardly worthy of notice. Nothing could be further from the truth, as we shall see. Most of these photos were taken either this fall, or the last. All of these species are at least fairly common in parts of Ohio and occur throughout much of the Midwest.

To learn more about the fascinating world of slug moths, get your hands on a copy of The Slug Caterpillar Moths (Lepidoptera: Limacodidae), and Other Zygaenoidea of Ohio. You can get one RIGHT HERE. Sounds a bit heavy, I know, but it's easily understood and includes a wealth of info about the interesting world that follows in this post. One of the book's authors is Dennis Profant, who lives in the Athens, Ohio area and manages this EXCELLENT BLOG.

This is a Stinging Rose Caterpillar Moth, Parasa indetermina, and it is one of the more distinguished of the slug moths. Most of them are just little brown jobs. Cool, if you are into moths, but not extraordinarily flashy. The caterpillars from which they are spawned are a whole other story.

This is a Stinging Rose Caterpillar, and what an extraordinary insect it is. They remind me of sea slugs - something far too exotic to be wandering the leaves of an Ohio forest. These cats aren't finicky eaters - they are polyphagous: capable of eating the foliage of many species of woody plants. This one is on American Beech, Fagus grandifolia.

One of the better known slug caterpillars is the Saddleback Caterpillar, Sibine (Acharea) stimulea. Those columns of spines will getcha! Many a person has learned just how painful the chemically fortified spines of caterpillars can be after touching one of these.

If not the most bizarre of our slug cats, the Monkey Slug, Phobetron pithecium, would be ranked near the top of the list. They don't even resemble caterpillars, or any other animal for that matter. One theory is that Monkey Slugs mimic the shed skin of a tarantula. That seems absurd here in Ohio - where we have no tarantulas - but this group is primarily tropical and found in areas where tarantulas are common. Why look like the cast skin of a giant spider? Well, who wants to eat such things? Looking untasty can be an excellent defense in the caterpillar world.

The Spun Glass Slug, Isochaetes beutenmuelleri, is undeniably outrageous. They are opaque, and the caterpillar's inner workings can be seen through the exoskeleton, like some sort of science exhibit come to life. The appendages are copiously beset with glassine hairs, and I suppose they can sting although I've never handled one to find out.

Tiny but beautiful, this Purple-crested Slug, Adoneta spinuloides, is about the size of the illuminated slug in the first photo. Blown up via macro photography, it becomes a thing of great beauty.

The well-named Elegant Tailed Slug, Packardia elegans, poses for your narrator.

Skiff Moth slugs, Prolimacodes badia, have an unmistakable shape. It may be that they mimic a leaf gall to better blend in. This species is quite variable in the coloration of the dorsal (upper) surface.

Here's another Skiff slug, and this one is clad in brown above. This coloration causes it to look like a patch of dead leaf tissue, and it would be incredibly easy to overlook this small animal.

Subtly beautiful, a Yellow-shouldered Slug, Lithacodes fasciola, feeds on a maple leaf.

Always a crowd pleaser, the Crowned Slug, Isa textua, looks a bit like a snowflake. This caterpillar is an outstanding example of the rewards of looking closely at VERY SMALL THINGS.

Finally, we'll end this slug parade with an utterly astonishing species, the Spiny Oak Slug, Euclea delphinii. They can vary in coloration from orange to pink to red, green, or yellow. No matter what color, it is a spectacular beast and sure to cause anyone to stop for a moment and inspect it.

There is still a week or two of good caterpillar hunting in this part of the world. Next time you're out and about in a wooded area, take time to inspect the undersides of leaves and you may run across some of these spectacular slugs.


Anonymous said...

I had no idea there were such wonderful caterpillars here in Ohio. I need to look more closely in the plants when I am out hiking.

I also wanted to pass along a link to one of my Flickr Contacts. He lives in China and posts a lot of images of caterpillars. If you like this blog article, you will like his images. (I sent him a link to this website.)

Even though the images I've seen from China are really nice, I am quite certain that the Ohio caterpillars could hold their own in a beauty contest with those from China.

Ken Andrews

DenPro said...

Thanks for the plug Jim. Very nice Spun Glass Slug. the moth is common, but I've yet to photograph the larva in the field.