It's National Moth Week!
A celebration of my favorite community science event, including Notes from Both Porches - After Dark Edition.
One of my favorite annual community science1 events, National Moth Week takes place during the last full week of July, plus the weekends that bookend that week. This year, it ends on Sunday, July 28th, so we still have a whole weekend to celebrate!
To participate, you can attend an event, host your own (even if it’s just you on your back porch), or simply notice and photograph the moths that you encounter. To contribute to National Moth Week community science data, upload your findings to a platform such as iNaturalist or BugGuide.
Notes from Both Porches — After Dark Edition
Reader, I had big plans for this post, that it would recount the results of nighttime mothing from July 2o-24, the first half of National Moth Week. I envisioned my backyard light sheet, glowing and ghostly in the dark, and upon closer inspection, fully decorated with insects. There would be moths, of course — the fringed white T’s of plume moths, the folded triangles of tubeworm moths, the distinctly geometric wings of tiny tortricids, and the surprising, shimmering gold detail on the white wings of otherwise unassuming grass-veneer moths.
Joining the moths would be miniature wasps and winged ants, electric green lacewings, and lots of beetles — weevils, perhaps a single colorful longhorn beetle, and the ubiquitous chafers: the light brown, round beetles that fly around on summer nights, banging into objects and people, later found in the morning desperately swimming in bird baths, dog dishes, or any vessel that has collected water.
But this year, the back porch light is broken, the front porch light refuses to stay on, and the last couple of nights it has rained, drenching the light sheet before any insects could land.
Regardless, it started out promising on the first night of National Moth Week, July 20th. Just above the front stoop, I spotted an orange-red moth. I managed one clear photo of Pyrausta rubricaulis (Variable Reddish Pyrausta Moth) before it flew away.
Taking this as a sign, my husband and I set up the front stoop for mothing, hanging a pale blue bed sheet across the entrance, with a reading light clipped to the overhang and pointed at the sheet. We checked at midnight, at 2:00 a.m., and just before sunrise.
The sheet was empty.
On the evening of the 21st, I noticed moths fluttering around the front yard, so I set up the light again. Awake before dawn on the 22nd, I went straight to the front stoop.
Nothing awaited me but darkness.
I decided to try a new approach — moth bait. According to the Internet, a paste of sweet old fruit and something fermented (such as alcohol) smeared on the trunks of trees would attract moths that may not care about artificial light. This is a recommended way to moth in winter, but it can be done at any time of year!
I scanned the kitchen, searching for ingredients. An extremely ripe banana lay, spotted and slouching, on the counter. Perfect. Into a mason jar it went!
In the pantry, I found a container of chopped dried guava purchased at the DeKalb Farmers Market in 2015. I think the project it had been destined for was “tropical” granola, an experiment that turned out overly sweet yet underwhelmingly bland. I cannot explain why we kept this dried guava, which we did not like and was purchased while I was still a law student. I added the dried guava to the banana mush.
Next, to the liquor shelf! Here I found a small hot sauce bottle containing leftover wine of indeterminate age, with a masking tape label in my handwriting that read “Cooking Wine.” Into the mason jar it went! I topped off the mixture with some sarsaparilla whiskey from a Toco Giant clearance sale. I decided that my husband would not miss the sarsaparilla whiskey that, like the dried guava, was purchased while Obama was still the president.
I let the mixture sit for a day or so before blending it to paste. Shortly before sunset on the 22nd, I applied the paste to the trunks of trees around my yard.
A few hours later, I went out with a flashlight to check the trees. The moth bait did not attract moths. I think you can guess what I found instead.
Cockroaches. Big, dark brown Periplaneta2 with long, waving antennae. Half a dozen or so crowded around the whiskey-guava paste. I stared, frozen, as more joined, crawling down the trunk of the tree. I glanced up, spotting giant cockroaches slowly marching along a leafy branch, heading down towards the feast I had unwittingly prepared for them. That was how I learned that Periplaneta cockroaches hang out in the tops of trees.
Meanwhile, the reading lamp and pale blue bedsheet waited on the back porch, so I left the roaches to their bounty. When I arrived on the back porch, dozens of chafers awaited me. Some rested, perfectly still, on the sheet. Some roamed around on the floor of the porch, in the golden circle where the reading lamp cast its glow. One circled the reading light, occasionally banging into the bulb with a faint ringing sound. Another zipped across the porch to greet me, crashing into my chest like a happy dog.
Although moths fluttered in both the front and back yard, disappearing into the darkness of the trees overhead, none were near the light sheet.
Each subsequent night this week, it has rained, and a respiratory illness has kept me indoors. Thus ends the first half of National Moth Week 2024 with very few moths observed by me. Instead, I’m providing general moth and general moth-observing information, with photos of some of my favorite moth discoveries over the years.
What are Moths?
Moths are all insects in the order Lepidoptera (which means scale+wing) that are not butterflies (Superfamily Papilionoidea.) But what does that mean in practical terms? How do I know, when I observe an insect, particularly during the day, whether it is a moth or a butterfly?
I thought I knew the answer to this question. From a Rutgers entomology class in 2006, a faint and hazy memory surfaces — something about “wing hinges.” When I turned to Google to double check this, I found myself in a spiral of confusion and misinformation based in overgeneralization — for example, butterflies are always diurnal and moths are always nocturnal. We know that’s not true! Just last week, I wrote about Ailanthus webworm moths (Atteva aurea), one of many diurnal species.
I turned to my field guides.
“The easiest way to tell them apart,” according to Seabrooke Leckie and David Beadle, writing in the Peterson Field Guide to Moths of Southeastern North America, “is by the antennae: if they are clubbed at the tip, it’s a butterfly; if they are threadlike or feathery, it’s a moth.”3 How do we tell the difference if we are not close enough to examine their antennae?
Unlike moths, butterflies usually rest with their wings folded, standing up straight above their bodies. Except when butterflies spread their wings flat to warm in the sun.
Whereas moths have chubby bodies, butterflies have slender bodies. (I think immediately of bulky-bodied skippers, butterflies in the family Hesperiidae.)
I turned finally to a butterfly field guide, the recently-published Butterflies of North Carolina, South Carolina, Virginia, and Georgia: A Field Guide by Harry E. LeGrand, Jr., Jeffrey S. Pippen, Derb S. Carter Jr., and Pierre Howard. Here I found my answer!
Besides clubbed antennae, what separates butterflies from moths is the lack of frenulum. This is the “wing hinge” from my distant college memory. The authors explain, on page 4 of the field guide, “The frenulum connects the forewings to the hindwings in moths. Butterflies lack frenula. While these structures are not observable in the field, they affect flight styles . . . butterflies have more control over all four wings independently.”
The guide continues on the next page, “Moths appear to fly much more erratically than butterflies, in part because their forewings are attached to their hindwings by frenula. Butterflies appear to fly purposefully and land purposefully. Moths look like they are flying out of control and crash landing into vegetation.”
Yikes. Aside from this unflattering description of their flight, the frenulum could explain why the wings of some moths (unlike those of butterflies) appear to fold, tentlike, over the moth’s body, and why for many moths, when the wings are outspread, the forewings (the set of wings closest to a moth’s head) obscure most of the hindwings (unlike those of butterflies.)
Why Care About Moths?
I’m hesitant to point out their aesthetic value, that not all moths are brown and boring, that many are as beautiful as butterflies — because beauty should not be a determining factor in whether or not a living thing is worth caring about. But there’s nothing wrong with appreciating them.
Like all insects, moths are an important part of biodiversity, in addition to the services they provide to our ecosystems. Many moths serve as pollinators. Moths also serve as food for birds, bats, and other predators. Without moths our backyards would be devoid of birdsong; many birds rely on moth caterpillars to survive. Moths and their ecological importance are a driving force in environmentally friendly gardening — or at least, they are for me. Planting a wide variety of mostly native plants—host plants for larvae— increases the abundance and diversity of moths, ensuring a food source for my backyard birds. Leaving the leaves (unshredded fall leaves) on the ground provides shelter for moths, especially in winter.
How To See More Moths
You can set up a moth sheet, as I described above, or leave an outside light on. But if you don’t want to stay up late, there are plenty of ways to see moths during the day.
Check flowers for daytime pollinators like the white-lined sphinx pictured at the top of this post or the Ailanthus webworm moth described last week. Check for moths resting flat against the sides of surfaces, like the luna moth pictured above on a tree, or the tulip-tree beauty resting on my house (pictured second in this post.) Look for signs of moths, tracks or structures they have left behind, such as pupae or leafmines.
On a walk in the woods, pay attention to the fluttering creatures that take flight when you approach. Litter moths (referring to leaf litter, not trash) lack the bright colors of more charismatic species — they will not likely be mistaken for butterflies — but with the intricate patterns of lines, curves, and spots on their brown wings, they have their own subtle beauty.
I hope I have convinced you to take a look at our underappreciated lepidopterans over the next three days (and beyond!) Even though my nighttime mothing has been a failure this year, I’ve got a whole weekend of daytime mothing ahead of me!
A note on language: I started using the phrase “community science” instead of “citizen science” after learning that many consider the former a more inclusive term. I cannot find the piece of writing that introduced me to the term and convinced me to use it, or I would link it here.
Periplaneta are the “outside kind” of cockroaches in the Southeastern U.S. They still find their way indoors but are not as distressing as Blattella, the pale brown cockroaches which can cause indoor infestation.
Except when they fly. The fact that Periplaneta seldom fly makes it all the more distressing when a mouse-sized insect alights from the wall and heads towards one’s face.
Page 9 of Peterson Field Guide to Moths of Southeastern North America.