Discovering Minnesota’s Diverse Moth Species

**Phalaenophana pyramusalis** (dark-banded owlet, Family Erebidae, Subfamily Herminiinae).

How many moth species does Minnesota have?

When I first started moth hunting in 2017, I had no idea how many species of moths live in Minnesota. My first experience with Minnesota’s moth numbers was from a moth survey report. There had been a Minnesota DNR moth survey of state parks from 2006 to 2008 along the eastern edge of the state. Its purpose was to document moth species present before LDD moth (Lymantria dispar dispar) control efforts.

Their final list, representing just a small portion of the state, was 768 species, although they believed that statewide, there are about 2,200. I wondered how many of those moths might be where I live.

So many moths are tiny

Early on in my mothing I noticed there were many tiny moth species. I found some moths the size of a thumbtack. Others are smaller than a grain of rice, like the three species below.

*Epermenia albapunctella* (Epermenioidea)

Identification is not so simple

Most people are familiar with the larger charismatic moths, like the luna moth or one of the sphinx moths. But for many of the moths out there, they are just moths. This is understandable. Identifying anything to species is not always easy. With moths, this task is even more challenging given their variety of sizes, colors, and often subtle differences in wing patterns. To make matters worse, some species exist in different forms or look like other species.

Acleris (Superfamily Tortricoidea, Family Tortricidae) is a good example of a genus with intraspecific variation. Some species even resemble others within the genus. I’ve included two photos of Acleris celiana showing two of the forms it exists in. There are also photos of other Acleris species, some of which resemble each other.

So, is that the final count?

By the end of 2019, I had identified 541 moth species. It seemed to me this was close to the upper limit of moth species present. After all, the DNR survey had documented 768 species in thirteen state parks. These parks range from the southeast corner of the state to the northeast corner. I am looking at only a tiny fraction of that territory. About 40 acres, to be exact.

My list surpasses the DNR’s list

Eventually, my species checklist surpassed the MN DNR survey’s list. After rechecking identifications, synonymy, and duplications, my list was at 865 species. That’s 97 species more than the DNR list. How to account for that?

Accounting for the differences

The differences in species counts are most likely due to our respective sampling methods and time available. The MN DNR survey’s list is almost entirely species from so-called macro-moth taxa. It is heavily weighted towards Geometridae and Noctuidae.

It is likely that the smaller moths, the so-called micro-moths, were not within the scope of the survey. It would have taken too much time to identify every moth. This would delay the report and critical action on Lymantria dispar dispar expansion into Minnesota.

So, while our lists overlap for most of the macros, my list also includes micro-moths. These include those from the superfamilies Gelechioidea, Nepticuloidea, Tineoidea, Tortricidae, and other taxa with mostly minute moths.

When I am mothing, I try to photograph and later identify every moth that comes to my moth light. I am not under any time constraints to complete fieldwork or produce a final report. Some unidentified moths have sat in my photo files for years before I figure them out. They needed to present the bigger picture. I am just filling in the details and have plenty of time to do it.

My checklist will continue to grow

I’ve been working on documenting the moths on my land for eight years. I don’t think I am done yet. I also don’t think annual additions to my checklist have peaked.

The rate of new species additions has been about 33 per year since 2020. As of 2025, the species checklist stands at 865 moth species with 34 new additions. This includes macros and micros. If that rate continues, the checklist will reach 1,000 species in about four years.

Mothing into the fall and even the winter

Autumn is upon us now. Soon, almost all insect life outdoors will be gone. In the meantime, I will continue to photograph right up until the snow falls and the lakes freeze. But even in winter, it is possible to find some insect life, including moths, outdoors.

*Operophtera bruceata* (hunter’s moth) flies in late October. It continues into November when night temperatures typically drop into the 30s and upper 20s.

Insects That Mimic Stinging Wasps: A Look at Synanthedon acerni

In a previous post, I wrote about syrphid flies that mimic bees and wasps. But are there other insects with this mimicry superpower? The answer is yes. Other types of flies, beetles, and moths all have species that mimic stinging insects. The moth Superfamily Cossoidea (Carpenter and Clearwing Moths) is notable for the many species that mimic stinging wasps.

Synanthedon acerni (Family Sesiidae, Subfamily Sesiinae, Tribe Synanthedonini) is one such very wasp-like moth. Its wasp-like appearance allows it to be active during the day while it visits flowers, feeding on nectar.

Life history

The larvae of Synanthedon acerni are not quite as benign. Known as the maple callus borer moth, its larvae bore into the trunks of maple (Acer spp.) trees. Eggs are laid near wounds in the bark. Entry into the tree is through these wounds on the tree’s trunk. The larvae bore into the bark and then into the cambium, where they feed on the inner bark and sapwood. Feeding takes place during the summer within galleries. In the winter, they hibernate in the galleries and resume feeding in the spring.

At maturity, the larva constructs an oblong cocoon of wood fragments, frass, and silk within the gallery, close to the surface, covered by a thin escape window. When ready to emerge, the pupa cuts open the cocoon and the escape window. The fully formed Synanthedon acerni moth then exits the pupa, which is left partially stuck in the gallery.

The same tree may be used year after year, weakening it and eventually leading to its demise. A callus will form on the trunk after repeated infestations.

Epermenia albapunctella: The Tiny Moth You Might Overlook

*Epermenia albapunctella* seen on July 21, 2020.

A speck of dust?

This strange looking gray insect is a moth, and it is very tiny, with a wingspan measuring 13 mm and a body length of around 7 mm (~0.27 inches). It belongs to the genus Epermenia. It may be Epermenia albapunctella, a moth in the Superfamily Epermenioidea (Fringe-tufted Moths), family Epermeniidae.

The first time I saw the moth was in July 2020. I almost passed it by, thinking it was a speck of dust. I’m glad I focused my camera on it because it was not dust but a living moth.

I saw this species two more times after that. Once on September 09, 2018, and again on August 01, 2023.

**My third sighting of *Epermenia albapunctella* on **August 01, 2023**.**

Species determination

While the species identity I have determined is provisional, it is a species of Epermenia. Identifying many tiny moths to species (and even some larger ones) is not always possible from a photo alone or even from visual examination of wing patterns and colors. Very often, genital dissection and DNA sampling are required. These techniques help resolve species identification where one or more related species look very much alike. They can also help to discover cryptic species.

There are numerous sightings of Epermenia albapunctella (MPG and iNaturalist), indicating it is a widespread and somewhat common species.

Epermenia larval host plants

The chief larval host plants of Epermenia are in the Apiaceae (carrot family). They feed by mining the leaves, but later feed outside the leaf in silk webs. However, I could not find information on the feeding habits for all Epermenia species.

Several wild plants in the carrot family grow locally: Cicuta spp. (poison hemlock), Heracleum maximum (cow parsnip), Sanicula spp. (snakeroot), Sium suave (water parsnip), and Osmorhiza spp. (sweet cicely). Feral plants of wild carrot (Daucus carota), parsnip (Pastinaca sativa), and caraway (Carum carvi) are found locally, too. And there are, of course, vegetable gardens with cultivated carrots. They are also Daucus carota, but tastier than the wild form, especially in carrot pie.

*Heracleum maximum* (Cow parsnip), a host plant for *Epermenia* moths. Common along the margins of wet woods and in ditches.

The local abundance of wildflowers in Apiaceae makes locating additional Epermenia moths and larvae more likely. Three species growing here in abundance and with the potential to host Epermenia are sweet cicely, spotted hemlock, and cow parsnip.

Future investigations

Next year, after winter has passed, I’ll be examining any plants in the Apiaceae for Epermenia larvae. I might even plant a carrot patch just for Epermenia. Why else would I plant anything if not for the insects that eat them?

Moths and Their Nighttime Floral Visits

*Xestia normanianus*, a dart moth, nectaring on lance-leaved aster (*Symphyotrichum lanceolatum*) at night.

What do moths do at night anyway? Some of them visit flowers for nectar.

Back in August, I was wandering about in the woods at night looking for foxfire fungi. At the head of the trail on my way out, I saw a sunflower plant with something on the flowers. It was a green tree cricket (Oecanthus) eating the stamens in the sunflower florets.

The next night, I went back but this time with my camera, hoping to find more tree crickets. I had my LED headlamp on like the previous night and used it to illuminate the flowers and foliage where I wanted to photograph. I also set the flash of my camera to “on”.

Although I could hear tree crickets in the bushes, I didn’t see any this time. What I did see were lots of moths on sunflowers and asters. Aiming the lamp’s beam at the flowers, I then pointed my camera at the moths and began taking photos. I wasn’t using a tripod, so many were blurry. Some were also overexposed by the bright LED light. But a few turned out.

*Feltia jaculifera* nectaring on a sawtooth sunflower (*Helianthus grosseratus*)

The moth species (Xestia normanianus, Feltia jaculifera, and Nephelodes minians) I found on flowers at night came as no surprise. These and other dart moth species are common visitors to my moth lights. But it was exciting to see them going about their normal activities in a natural setting. I never did find any foxfire this year.