As always, click the photo to enlarge
An American Dagger (Acronicta americana) moth caterpillar noshes on the leaf of a Red Maple (Acer rubrum). We saw many of this species on this evening. American Daggers are polyphagous - they can eat the foliage of scores of plants. It is often one of the most common caterpillars we find on night prowls, if not the most common.
Last Saturday, August 22, Shauna and I headed southeast and into the hills of Jackson County. This is one of the most biodiverse counties in Ohio. We headed towards the property of Julie and Rod Sheets, friends that we met last spring during a flying squirrel research project that took place on their 195 acres. After traipsing over some nice swaths of the place during the squirrel project, I probably commented to Rod and Julie that "this place would be great for moths/caterpillars!"
And there we were, returning at a peak time for lepidopteran subjects. While the mothing (if you're new to the term, "mothing" entails luring moths to an illuminated sheet) was a bit tepid, their larvae were quite robust and put on a great show. And some of these caterpillars are featured here.
Usually, between keeping an eye on the sheet for moths, we search nearby habitats for caterpillars. Our efforts are greatly aided by the use of blacklight flashlights ("UV BEAST" is a good brand). A great many caterpillar species fluoresce, often quite brightly, when caught in our purple beams.
We didn't make it 20 feet from the sheet when Shauna shouted "look!" She had found not one, or two, but three!! Saddleback Caterpillars under a single redbud leaf. That fortuitous find proved to be a good omen, and we went on to find many more interesting larvae. Some photos of those follow.
A Banded Tussock Moth caterpillar (
Halysidota tessellaris). This species vies with the American Dagger for the most frequently found cat. It, too, is polyphagous and can seemingly ingest anything. Such a catholic diet is not the norm for caterpillars. Far more caterpillars are specialists, eating only one family of plants, one genus, or even only a single species. Nonnative plants species do very little for caterpillars. Most can't eat them, due to long-evolved chemical compatibly with only their host plant(s).
We were pleased indeed to discover this fully grown Elm Sphinx Moth caterpillar (
Ceratomia amyntor). This species is a hyper-specialist, eating only plants in the elm family, and only those in the genus
Ulmus. The Sheets' property has plenty of American Elm (
Ulmus americana) and Red Elm (
U.
rubra), and I was watching for one of these four-horned beauties. In my photo, it is rearing up in what appears to be a defensive posture that they often adopt when disturbed.
If you noticed how leaf-like the Elm Sphinx cat is in the first shot, this one should reinforce that. The larva clearly mimics the elm leaf both in color and venation. I couldn't get this one to cooperate very well, as I was trying to pose it so that its raised white stripe that runs the length of its back was aligned perfectly with the leaf's central midrib. That's how they often rest when not feeding. The caterpillar's angled lateral lines then mesh perfectly with those of the leaves.
This is a Hackberry Dagger Moth caterpillar (
Acronicta rubricoma) and it wasn't even on my radar. I'd never before photographed one and can't remember even seeing one. But I don't keep a list and there are LOTS of bugs and I can't remember them all.
Anway, the aptly named Hackberry Dagger is a hackberry feeder, and hackberry is also in the elm family. It also apparently eats elm, and weirdly, it is claimed that they will also consume sumac (unrelated family). I checked Ohio records in iNaturalist, and while the species has been recorded statewide, records were rather sparse and scattered and probably the vast majority of those records were of the adult moth phase rather than caterpillars.
I've long wondered about the vertical stratification of caterpillars feeding in trees, and whether there might be a suite of species that typically feeds in the crowns. It may be that there are certain cats that are hard to clap eyes on because they are usually high overhead and out of sight. Maybe the Hackberry Dagger is one of them. There, now 43 people will tell me about all of the Hackberry Daggers that they encounter :-)
An Io Moth caterpillar (
Automeris io) makes an artistic stinging edge to a dogwood leaf. Those envenomating spines will make you rue touching one. I did so accidentally once, and it was akin to an especially potent Wood Nettle (
Laportea canadensis), the most painful of our nettles. The Io cat is also polyphagous and probably the most commonly encountered silkmoth caterpillar, at least for me.
We did well with the always interesting slug moth caterpillars such as this Jewel-tailed Slug (
Packardia geminata). Some species resemble snails, as this one does. Its head, on the right, is extended; it's frequently not visible.
The reason for the insertion of "slug" into the name of this group is due to their curious method of locomotion. Instead of a series of central prolegs, slugs have sets of paired suckers. They glide along on a thin film of silk, much like a slug moves.
Here's the trio of Saddleback Caterpillar Moth caterpillars (
Acharea stimulea) that started off the night prowl. In the words of entomologist and caterpillar expert Dr. David Wagner, slug caterpillars are "more fantasy than reality".
This species has one of the most painful stings of any North American caterpillar, so look but don't touch. Those columnlike extensions are bristling with envenomating spines. There is a venom sac at the base of the spine, and when triggered it blasts the hot sauce into the interloper like an injection from a hypodermic syringe. While stings will probably hurt anyone that experiences it, some people can react very badly.
A Saddleback cat resembles a little tubular chestnut horse draped with a lime-green horse blanket. Unfortunately for the larva in my photo, it is a walking dead caterpillar. Near the top left of its body, where there is a thin band of green, it looks like someone put a tiny cigarette out. That's either an air exchange hole for the larva of a tachinid fly, or its exit hole. Either way, the caterpillar won't survive the internal ravages of the fly maggot. Such parasitoidism is very common in the caterpillar world.
Yet another slug moth caterpillar and it isn't the last (almost, though). This is a White Flannel Moth (
Norape ovina), and it is an outrageous insect. Check out those uber-long setae, and the showy jewel-like studding on the body. Those "jewels" are also studded with envenomating spines, and the sting is said to be quite painful (I could talk no one into getting stung so that we could learn about this).
Finally, insofar as the slugs go, here is our grand finale: the utterly bizarre Lesser Parasa Moth (
Parasa chloris). Dr. Seuss himself couldn't make this thing up. To me, from certain angles, they look like hippopotami. This parasa is actively feeding and its head is tucked out of sight.
This is a White-dotted Prominent (
Nadata gibbosa) and it's primarily an oak feeder. This one is apparently preparing a temporary bivouac by spinning a thick layer of silk. As the silk dries, the leaf will fold over the cat, concealing it. White-dotted Prominents are pretty common but always interesting. When agitated, they can perform an amazing act that suggests snake mimicry. I show a photo of one so engaged and describe that behavior
RIGHT HERE.
Saddled Prominent Moth caterpillars (
Cecrita guttivata) may be common, but they are quite showy. When one presents itself as nicely as this one did, I find it impossible to resist making photos.
Caterpillars grow through phases termed instars, and each instar stage is separated by a molt. Most of our larger species go through five instars excepting the slug caterpillars which typical have seven or even nine instars.
This is a Sycamore Tussock Moth caterpillar (Halysidota harrissii) and it is fairly young in its growth, probably in its third instar. At this stage, it eats holes from the centers of leaves of its host plant. And that host plant is the Sycamore (Platanus occidentalis). Nothing else will do for this extreme specialist.
Lastly, a fine pair of leaf-edge mimics. This one is the Checker-fringed Prominent caterpillar (
Schizura ipomoea). We caught this one in transit, but when ensconced along the edge of a leaf dappled with browning necrotic tissue, the green and brown caterpillar can be quite hard to spot. The jagged back extensions provide further disruptive camouflage.
This one may one-up the previous species in the leaf camouflage department. It is a Red-washed Prominent caterpillar (
Oligocentria semirufescens). From any distance, the cat - which usually hangs out on a leaf's edge - can be remarkably difficult to see, as it so greatly resembles senescent browning leaf tissue.
Major thanks to Julie and Rod for inviting us over to explore, and for all of their conservation efforts which include many fine cats.