Late in the summer, I was hiking along a trail in southeast Ohio when I found something very unexpected. I glanced down at some blooming Butterflyweed alongside the trail and noticed that the plant held two orange caterpillars with tufts of gray hairs. They were Unexpected Cycnias, a rare species of moth that is endangered in the state of Ohio!
I absolutely love moths, and I’m a big fan of all things unusual and rare. The Unexpected Cycnia checks both of those boxes, and I’ve been wanting to see them for years now. However, not only are they difficult to find because they’re rare, but they’re not even supposed to be in southeast Ohio. These two Unexpected Cycnia caterpillars were county records (for Athens County, Ohio), and one of the handful of records from southeast Ohio at all.
To say I was excited to find these two caterpillars would be an understatement. This has, by far, been one of my most noteworthy finds to date. In this post, I’ll spend some time digging into what this little-known moth is, why it’s rare, and what it suggests about the history of the area it was found in.
The Unexpected Cycnia
The Unexpected Cycnia (Cycnia collaris [formerly C. inopinatus]) is a moth in the family Erebidae, also known as the tiger moths. It is found scattered throughout the eastern United States, with populations in the Great Plains, Midwest, Southeast, and along the Atlantic Coastal Plain. But despite its wide range, it’s not common anywhere, and is often quite rare where it is found. This is especially true here in Ohio, where it is extremely rare. In fact, up until recently, the Unexpected Cycnia was only known from two locations in Ohio: the Oak Openings Region of northwest Ohio and Lynx Prairie in southern Ohio. Since then—often thanks to the work by community scientists—more individuals have been reported in southwest and west-central Ohio.
The Unexpected Cycnia is rare due to habitat destruction and degradation. This is a species of open grasslands. Sadly, countless acres of prairies, savannas, and other open grassland ecosystems across the eastern United States have been lost over the past 200 years. Many such areas converted to farms, cities, and other land uses, while other areas were degraded or converted to other ecosystem types—such as dense forests—because of fire suppression and other changes to the natural disturbance regimes. As the habitat for the Unexpected Cycnia decreased, so too did the global population.
The habitat of the Unexpected Cycnia is but one piece of the larger picture. Like many species of moths and butterflies, the Unexpected Cycnia has a narrow set of plant species on which the caterpillars will feed. In this case, the Unexpected Cycnia is a milkweed-dependent species, similar to the Monarch butterfly. And it’s not just any milkweed species that the caterpillars will feed on, either. The Unexpected Cycnia feeds primarily on Green Milkweed (Asclepias viridis), Butterflyweed (A. tuberosa), and Whorled Milkweed (A. verticillata). These three milkweeds are all species of prairies, savannas, and other similar grassland ecosystems.
Because the Unexpected Cycnia requires a certain subset of milkweed species to be available for the caterpillars to feed on, you will only ever find this moth in areas where these milkweeds are growing. Historically, this meant the moth would have been found in ecosystems where such milkweeds were part of the normal plant community, such as tallgrass and mixed grass prairies, savannas, barrens, glades, and the likes. This explains why one can find this species living in the oak savannas of the Oak Openings region of Ohio, or the shortgrass cedar glades of Adams County in southern Ohio.
However, I did not find these two caterpillars in a prairie or similar “natural” ecosystem. Instead, I found these two munching on a Butterflyweed that was growing in an old field that used to be a train depot. This train depot was used for loading coal from nearby mines in the late 1800s and early 1900s, but when the mines closed, so too did the train depot. After the depot was abandoned, a field slowly took over. The field resembles a prairie, and it contains a population of the host plant Butterflyweed, and so it functions as an appropriate habitat for the Unexpected Cycnia. This isn’t a new phenomena, as “old fields” have been noted to be an appropriate habitat for the Unexpected Cycnia—as long as their milkweed hosts are available.
Luckily, this old field is not in any immediate danger of being converted to something that the Unexpected Cycnias cannot persist in. The field belongs to a village in southeast Ohio, and is the site of a trail system. However, without any eco-management to maintain this field as a prairie-like system, there is a longer-term concern that natural succession will ultimately lead to this field turning into a young forest system, which will cause the Butterflyweed population to be shaded out of existence—ultimately rendering this area ineffective at sustaining an Unexpected Cycnia population. But that is an issue for another time.
An Insight into the Past
So why was a moth of grasslands found in an old field in southeast Ohio, a rugged part of the state known for its extensive forests? You might initially think that some adults—which can fly—simply moved in from some area that held a population, a process called dispersal. And while that is true at face value, there’s some very important nuance to unpack.
The Unexpected Cycnia is a terrible disperser. In fact, adults are only thought to be able to disperse around 900 yards, or half a mile, max. This suggests that there had to be a source population somewhere within half of a mile of this field in order for some of those individuals to disperse into this new location, which is less than 100 years old. But southeast Ohio is known today for forests and not grasslands. It seems contradictory that a grassland species with poor dispersal capabilities would find its way into a small field nestled within a primarily-forested region, but the answer lies in history. This region wasn’t always primarily forested, and the presence of these two caterpillars isn’t a new phenomenon, but is instead a relic of the past.
The Prairie Peninsula
Beginning around 8,000 years ago, the climate in and around Ohio became hotter and drier as a post-glacial xerothermic period began. The water-loving forests that were covering most of Ohio at the time struggled in this new climate, and vast swaths were replaced by grasslands that moved eastward into Ohio from the Great Plains. This phenomenon is known as the Prairie Peninsula, and for several thousands of years much of Ohio featured grassland systems like prairies and savannas. And as the grassland plants—including milkweeds—moved east into Ohio, the Unexpected Cycnia followed.
The Prairie Peninsula extended into parts of southeast Ohio as well. In fact, pollen records a few miles away from the field where I found the Unexpected Cycnias suggest that this broader area was more prairie than forest from around 1,000 BCE to roughly 1400/1500 C (note: there still would have been patches of forests, but these would have been limited to areas that were more conducive to them, such as along streams and in moist ravines). It was undoubtedly during this period that the first Unexpected Cycnia moved into what is now the Athens County area. While this shift from a tree-dominated landscape to a grassland-dominated landscape was originally kicked off by a climatic change, these grasslands were later maintained by fires set by the American Indians for eco-management purposes after the climate shifted back to a cooler and wetter regime around 1 CE.
However, a series of events—including pandemics and the Beaver Wars—led to much of southeast Ohio being abandoned by American Indian settlements from roughly 1500 CE to 1700 CE. During this period, the trees re-exerted control, shifting the grassland-dominated landscape to open woodlands (which we now know were more widespread during this period than previously thought) and more closed forests.
However, some specific locations throughout this area resisted this woody encroachment due to factors like harsh soil conditions, bison wallowing and grazing, and fires set by first by the Haudenosaunee Tribal members using this area for trapping and later the Shawnee and Lenni Lenape (Delaware) Tribes which moved back into this part of southeast Ohio in the early 1700s. These scattered remnants of the Prairie Peninsula that were maintained through various ecological disturbances and geologic “good luck” undoubtedly harbored a population of Unexpected Cycnias and helped bridge the time from when they first moved into this area to the present.
When Euro-Americans first began pushing into this area in the mid to late 1700s, they made mention of the openness of the trees, the scattered “meadows” in the bottomlands, and the “barrens” in the uplands. The area between what is now Nelsonville and The Plains had a particularly high concentration of these “meadows” and “barrens,” and the locals collectively referred to these areas as “buffalo beats” due to the fact bison liked to graze in them. These buffalo beats were actually remnants of the original Prairie Peninsula grasslands. Sadly, nearly all of these buffalo beats have since been lost over the past 200 years. One high-quality example does remain in the Wayne National Forest, which is known as the Buffalo Beats Research Natural Area.
Because of the poor dispersal capabilities of the Unexpected Cycnia, and because of the history of the land in this part of southeast Ohio, it seems rather likely that these “buffalo beats” grassland remnants acted as refugia for these rare grassland moths. While the Unexpected Cycnia was probably more widely-distributed throughout this region during the height of the Prairie Peninsula period, only a few areas here maintained the habitat features needed into the present day, and it was in these areas that they maintained a foothold. They aren’t the only such grassland species to persist into the present thanks to these refugia. This broader area also features uncommon grassland species like Rattlesnake Master (Eryngium yuccifolium), Savanna Blazingstar (Liatris scariosa var. nieuwlandii), and others that are more typically encountered in more westerly or southerly prairies and savannas. These, too, are relics from another time.
However, without regular ecological disturbances to beat-back the encroaching trees, the open, grassland areas scattered throughout this area are in danger of transitioning to shady forests. If that happens, any and all species that require sunny, open areas either directly (such as the rare Rattlesnake Master) or indirectly (like the Unexpected Cycnia) will find themselves fading away. Luckily, some of these open areas happen to fall within the Wayne National Forest boundary and are actively managed by the Forest Service to maintain their openness. This eco-management will help sustain the uncommon and rare species that call these open areas home into the future.
Are There More?
While finding these two caterpillars was noteworthy, it’s not the end of the story. This record only raises more questions. Butterflyweed is not uncommon in this general area, and it can often be found growing along roadsides, in fields, in right-of-ways, and in small grassland remnants of the Prairie Peninsula. Do these areas hold Unexpected Cycnias as well? If so, how widely distributed throughout this broader area are they? The Unexpected Cycnia is well-camouflaged, and can be easy to miss if people aren’t looking for it. Maybe people have just missed an entire population—albeit very fragmented and in a region you wouldn’t expect—right under their noses.
Come summer 2021, I will be venturing into public places throughout this area and trying to see if there are any other places I can find this rare moth. This species is easiest to find when searching for the caterpillar, so there is a relatively easy path forward: 1. Find all open areas within 0.5 miles of the field that held these two caterpillars, 2. Search those areas for Butterflyweed populations, and 3. Search all Butterflyweed plants for caterpillars. If I find more caterpillars in a new area, I’ll map all open areas within 0.5 miles of that new area and search those. Repeat as much as possible (there’s a lot of private land I won’t be able to search). If I find any other places harboring the moths, I’ll pass that information along to the Ohio Department of Natural Resources Division of Wildlife.
As simple of a plan as that is, this species isn’t always a reliable find when surveying for them. If disturbed, they will drop to the ground and hide in the duff, and so you might search a Butterflyweed plant and miss a caterpillar. That means each open area with Butterflyweed will need to be visited several times to be thorough. But given the current world circumstances, there’s not much else I’ll be doing!
Thanks for reading!