To me, any time I go outside I am walking through new terrain, and am forced to slow down, pay attention and learn something new (and old). This is what a hike means to me. I want to always be able to hike in nature-not through it.
I find I have to constantly keep my knee-jerk reactions to certain insects in my garden in check. I tend to have an us vs them mentality when it comes to insects that I find feeding upon the foliage of plants I hold near and dear to my heart. I planted a hedgerow a number of years ago that is just starting to flourish. In it grow a variety of native shrubs-spicebush, elderberry, chokecherry, serviceberry. The idea is to create safe harbors and food sources for native insects and birds. Last week two different caterpillars showed up on the serviceberries. These two caterpillars perfectly illustrate my sometimes conflicted reaction to the insects that eat my plants-a tiger swallowtail caterpillar and some yellow-necked caterpillars (Datana ministra).
Tiger swallowtail caterpillars are adorable: medium-sized plump green caterpillars with a swollen thorax (the segment right behind the head, which in this case covers the head) sporting two prominent false eye spots used to scare away would-be predators. The flying adults are large yellow and black butterflies with the dangling tails, fairly common in this area. There are two similar tiger swallowtails found in this area. The range of the Eastern tiger swallowtail (Papilio glaucus) extends further south and the Canadian tiger swallowtail (Papilio canadensis) further north. To make things more confusing, these two species hybridize in central New England-so this particular caterpillar might be a cross between the two species. Since it is difficult to distinguish hybrids from Eastern and Canadian tiger swallowtails, I have referred to this caterpillar as a tiger swallowtail-that much I’m sure of.
Yellow-necked caterpillars are cute in their own way-dark heads, a bright yellow segment just behind the head (hence the name), with sporty brown and yellow stripes running the length of their bodies. But they lack those engaging cartoon eyes and, more importantly, they are very gregarious-I counted at least 50 on the serviceberry bush. Groups of ten or more were clumped on the branch tips, actively stripping the serviceberry of its outermost leaves (unlike the low-key solitary tiger swallowtail). Later this summer they will burrow into the ground to overwinter before emerging next spring as small moths. Instead of the delight I felt upon seeing the tiger swallowtail caterpillar I immediately began planning their demise.
If you do a search on tiger swallowtail caterpillars you’ll find lots of interesting life-history, nothing about ‘control’ since these are not considered a pest species. Yellow-necked caterpillars, on the other hand, are considered pests. They can cause damage to planted fruit and shade trees, but in their natural environment, in a forest for example, they do not significantly damage their host trees.
The purpose of my hedgerow is to provide food and shelter for native species. Both the tiger swallowtail and the yellow-necked caterpillars are doing what comes naturally, feeding on the leaves of the trees and shrubs in my hedgerow. Both of these species provide food for birds, predaceous bugs and parasitic flies. As I considered the fate of my yellow-necked caterpillars I realized that removing them meant removing a food source for others as well as contributing to the decline of a native insect. I figure that if the yellow-necks feed according to plan they will defoliate just the outer branches of my serviceberry bush. If I’m lucky some robins (robins evidently love yellow-necked caterpillars) will discover them and provide a little bit of control. But if not, my serviceberry should survive this natural pruning, and hopefully next year will support even more backyard diversity.
The following are three separate articles I wrote about the giant Polyphemus moth. 2 from the summer of 2009, one from this week. My Polyphemus moth sightings are few and far between! All three published in area newspapers and online with Seacoast Media Group
The Giant Polyphemus Moth is in the woods near you
Published July 13 2021 by Seacoast Media Group, Foster’s Daily, the Portsmouth Herald, York Weekly, York County Coast Star and more
Who doesn’t get excited upon finding a huge moth? While we don’t have the diversity of butterflies and moths found in the tropics, we do have some remarkable species up here. The one I found the other day isn’t colorful, but it is huge with striking markings–the Polyphemus moth. The Polyphemus moth (Antheraea polyphemus) is the most widely distributed of the giant silk moths in North America. The ethereal luna moth (Actias luna) is another large, common and well-known silk moth. These aren’t the kind of silk moth that are used commercially to spin silk, instead the giant silk moth’s silk is exclusively used to spin cocoons.
Adult Polyphemus moths don’t have mouths! Their only goal is to mate.
While these are common moths, I have seen very few and my experience is tinged with tragedy (the last one I found had an unfortunate encounter with my dog’s water bowl, before that I found one forlornly wandering the woods with a missing wing) so it was nice to find a fairly healthy specimen. He looked old to me, one of his wings had a big chunk missing (yet he could still fly quite well). Given that the adult Polyphemus moth typically lives for less than a week he must of had an exciting time in his brief existence as an adult moth. I knew this moth was a ‘he’ because Polyphemus moths exhibit differences in their antennae (sexual dimorphism), the males’ have big bushy antennae–giving the antennae lots of surface area to help detect pheromones released by the females (females have less bushy, more slender antennae). This is important because Polyphemus moths need to find each other quickly. Polyphemus moths overwinter in their silken cocoons, the adult moths emerging in late spring and early summer. Adults don’t eat, they don’t have mouths (which is weird to think about) their only point in life from here on out is to mate and lay eggs. Mating usually takes place within a day after emergence.
The females lay their eggs (singly or in groups of 2 or 3) on a host plant. The caterpillars feed on a wide variety of deciduous trees, for example, oaks, maples, willow and birch, all of which readily available around here. The young don’t descend as a horde like some caterpillars, instead Polyphemus caterpillars are solitary, eating the entire leaf and then snipping it off at the petiole (stem). It is believed that this is a protective measure against predators that look for leaf damage as a sign of potential caterpillar prey. Eventually the caterpillar will spin its cocoon-you can find these attached to a leaf on the host tree or sometimes among debris on the forest floor – and spend the winter getting ready for its finale as one of the largest moths in North America (wingspans can reach almost 6 inches!). It’s giant silk moth cousin, the cecropia moth, which also can be found in New England, is the largest with wingspans that can reach 7 inches across.
Polyphemus moth ID
How to identify a Polyphemus moth? The adults can vary a lot in color-from tan to reddish brown to dark brown. To me the defining feature is the large eyespot on each hindwing. All four wings have a transparent eyespot surrounded with yellow. However the hindwing eyespot is further outlined with a deep blue that deepens to black, it really looks like an eye. In fact, the species and common names for this species, come from the giant cyclops, Polyphemus, who had a single eye in the middle of his forehead. This was the cyclops who trapped Odysseus and his men in a cave and proceeded to eat them until the wily Odysseus blinded him and escaped. The eyespots on the moth are used to scare away predators. With the wings folded up the moth is expertly disguised as a dead leaf. If that doesn’t work, flashing those huge eyes at a predator will often scare it away.
I know going to the beach or a lake seem like more summery things to do here in New England, but how about a moth hunt? Many of the giant silk moths are most active right now-look for them clinging to a windowsill or the side of a shed during the day and flying around lights at night. They are one sign of summer you don’t want to miss.
From Caterpillar to Moth
Published October 1, 2009
In June I wrote a column about an unfortunate Polyphemus moth that hatched out of its cocoon in my kitchen and failed to survive a fall into the dog water dish.
Fortuitously a reader in Pennsylvania read this column and wrote to me after rescuing a beleaguered Polyphemus moth from a parking lot. She, Carol Guenther, jewelry designer and now caterpillar-wrangler, built an enclosure for the moth, watched it lay eggs, 78 in all, followed along as the eggs hatched into gorgeous caterpillars and recorded their growth and development from egg to cocoon to moth (usually these moths have to overwinter as pupae).
Polyphemus moths are one of our largest moths, they can attain a 5½-inch wing span. Their name comes from the eye spots on their wings, after the one-eyed Cyclops, Polyphemus, from “The Odyssey.” These eye spots are a nice example of a defense strategy called mimicry. They hide out, looking a lot like a dead leaf or dead wood, but if this disguise doesn’t work, they flash the eyespots on their hindwings, mimicking an owl’s eyes, and hopefully, startling would-be predators.
Aside from mating, the majority of a Polyphemus’ life is spent as a caterpillar; as a caterpillar they eat and grow. They will molt four times before spinning a cocoon. With each molt they increase in size.
Carol, lucky and patient person that she is, had the opportunity to observe the whole process.
“As I was putting some of them back in the cage I noticed one who’s head plate was half way down the new head. I knew that it was going to happen soon so I took it to my studio and set up to watch. As I looked closer, I could see that the skin looked funny, like tiny white wrinkles running vertically. I then realized that it probably was beginning to move about inside the skin in order to molt. I grabbed my chair and the camera and sat there. It indeed happened and I shot photos during the whole process. I forgot to check the time but I think it took about an hour.
″ … They apparently attach and secure themselves to whatever they are hanging from and then slowly move forward. When it’s over the skin is attached to the twig.”
Like all caterpillars, Polyphemus caterpillars are vulnerable to a slew of predators. Aside from being green to help blend in with the leaves they eat, after munching on a leaf they chew through the petiole, the leaf stem, disposing of the “evidence.” Smart predatory birds often use holes in leaves and chew patterns to target their caterpillar prey.
Carol’s caterpillars stayed with her for a few months, eating and growing. Finally, they were ready to pupate; to construct a cocoon within which they would undergo their transformation into adult flying moths. To do this they wrapped themselves in a leaf, bound into a case with silk. The case then hardened and turned brown.
Once metamorphosis was complete, the Polyphemus moths in all their glory emerged and flew off into the night.
Wouldn’t it be wonderful if we could all get to know an insect as intimately as Carol did? Polyphemus moths and thousands of other beautiful beings share our backyards, largely unnoticed. I think all of us could learn a lesson here; to stop and really look at something, explore, find out about what is out there and try to understand it.
Catch (and release) your own Polyphemus moth
Published July 9, 2009
This story with a tragic ending started with an egg case given to me by a friend in the dead of winter. We thought it belonged to a praying mantis so I kept it on the kitchen counter, eagerly awaiting the “birth” and dispersal of hundreds of baby mantids; not too thoughtful on my part, since emerging into a kitchen isn’t quite the same as the garden of insects these baby predators instinctively expect.
But instead of praying mantids, at some point a moth hatched from the cocoon. I missed the event but did notice later what I thought was a leaf in the dogs’ water dish. The leaf turned out to be a large moth that must have struggled out of its cocoon, walked a few halting steps to the edge of the counter and plunged down into the water dish.
Tragic enough if it had ended there, but the moth was still alive, a beautiful, giant fuzzy brown moth with crinkled wings. The wings were glued shut, probably because it had floated in the water dish instead of perching on a branch. There is a lovely yet sad part in the Annie Dillard book “Pilgrim at Tinker Creek” where the author remembers a similar event from her childhood, her last memory being ” Someone had given the Polyphemus moth his freedom, and he was walking away …; crawling down the driveway on six furred feet, forever.”
My doomed moth, I believe, based on its size and the hints of color I could see in its devastated wings was also a Polyphemus moth. These are magnificent moths, named for the eyespots on their hindwings; Polyphemus was the one-eyed Cyclops from Greek mythology.
Part of a larger family of moths, known as the silkworm moths or the Saturniidae, the Polyphemus is North America’s most wide-ranging Saturniid (wing spans can reach 6 inches) living east of the Rockies from Canada to Mexico. A familiar cousin is the stunning Luna moth, a ghostly pale green inhabitant of the deep woods.
These moths exhibit something called sexual dimorphism, meaning differences in the genders. Female bodies tend to be a bit larger than the males, especially when carrying eggs, and have smaller antennae. The males have strikingly large, feathery antennae which they use to detect the pheromones given off by the females. My moth was a male. I didn’t have a female to compare him to, but the antennae were unmistakable.
Polyphemus moths do not eat; like the rest of the Saturniids, they emerge from their cocoons with vestigial mouthparts. Their adult lives are devoted to reproduction. Finding a mate is a special event as this is the short-lived (the moths live just one week) last gasp of the Polyphemus life cycle.
My moth’s life ended in tragedy. I couldn’t bear to let it crawl away, dragging itself to its doom, to be killed by a chipmunk (the image evoked in Annie Dillard’s book was just too haunting and sad), so I froze it and left it by a log to be gently decomposed and returned to the earth.
It is relatively easy to find Polyphemus cocoons as they stand out against the snow of winter, and many people have successfully hatched out the moths. If you want to try this, make sure to house the cocoon in a container large enough to allow the moth to unfurl its wings before they dry shut.
If you would rather see a Polyphemus moth in the wild, check your outside lights at night, or better yet, make a moth trap by stretching a white sheet between some trees in front of a light bulb. You will, hopefully, be amazed by the throngs of unusual nocturnal insects that are attracted to the light and settle on the sheet. (07-13-21 note-as I learn more I become more uncomfortable with attracting wildlife. Nocturnal moths life cycles are already highly disrupted by outdoor lights, why add to the problem? I also now think it is a bad idea to raise moths in captivity. This definitely disrupts a monarch butterfly’s ability to migrate and might, similarly, interfere with natural cues necessary for moth survival. )