Moth or butterfly? Butterflies like this Leonard’s Skipper are moths! Photo by Joshua Mayer
When I think of the order Lepidoptera, it’s easy for the images of brightly colored butterflies to overshadow the generally night-flying and dull-colored moths. However, it is important to acknowledge that the butterflies we see in daylight hours are just the tip of the iceberg as nearly 90% of species in the order Lepidoptera are moths. When asked about the distinction between moths and butterflies, Kyle replied that there wasn’t one: “owls are a group of birds, and butterflies are a group of moths.”
The goals of the Goose Pond moth survey are to develop a baseline moth list, determine what species restricted to prairies have found their way to Goose Pond, and learn about one of the most cryptic and diverse assemblages of organisms on the planet. What group of herbivores do you think eats the most plant matter in an average terrestrial ecosystem? No it’s not deer, rabbits, mice, or even all mammals lumped together. It’s butterflies and moths! This group of insects contains 180,000 described species which comprises about 10 percent of all described species recorded. Their immense influence on plant communities cannot be overstated.
Kyle Johnson is an expert on moths and butterflies of the boreal forest and fens, and works as a private contractor mostly in Minnesota on their DNR’s moth and butterfly inventory. During Kyle’s last visit to Goose Pond in September 2015, he confirmed the state-endangered Silphium borer moth and their robust population, and identified 66 additional species during that survey.
We were also fortunate to have Angus Mossman help survey moths while Kyle was here on June 29, 2022. Angus lives in Sauk County with his parents Mike and Lisa, and has surveyed moths on their property over 100 times and has identified over 500 species, including the state-endangered Silphium borer moth. He predicts that the Silphium borer moth may be downgraded from state-endangered due to the large number of prairie restorations and their mobility. Although Angus has only been studying moths for about three years, Kyle was very impressed with his knowledge.
Kyle, Angus, and Goose Pond staff and volunteers gather around the light trap to look at incoming moths. Photo by Maggie Honig
Kyle and Angus set up light traps in Wood Family prairie and Browne prairie to attract the moths for identification. The light traps utilized ultraviolet and mercury vapor lights to attract insects to a white sheet hung between two poles. However, moths were not the only late night visitors to the sheet! We also attracted and identified insect species found in wetlands such as water boatmen, mayflies, caddisflies, wasps, ants, hoverflies, and more. Although most of Goose Pond’s moth species fly and pollinate plants at night, a few species are day-fliers and are not likely to be seen during night surveys. Day-flying moths observed at Goose Pond include the eight-spotted forester moth, the chickweed geometer (this species was also observed during the night survey), and the Virginia ctenucha moth, which was seen in large numbers during Goose Pond’s butterfly count.
Mark’s favorite moth of the night, the ‘Bird-poop moth’, among smaller moths, caddisflies, and other insects. Photo by Maggie Honig
Kyle and Angus found several moth species at Goose Pond who rely on specific host plants like Silphiums (cup plant, compass plant, prairie dock, and rosinweed), lead plant, meadow rue, rattlesnake master, etc. For example, Mark’s favorite moth of the night was the ‘Bird-poop moth’, Eucosma giganteana, that mostly feeds on the roots of cup plants and compass plants, both of which are abundant at Goose Pond. It is a mostly white linear moth with a brown splotch at the end of its body, aptly named as it resembles a bird dropping. A number of these moths were seen throughout the night, and they were one of the few moths that were easy to identify!
Another frequent visitor that was easy to identify was the tent moth, which quickly became a favorite due to its large size and cute, fuzzy body. Although this species’ moth form was loveable, many view their larval stage, the tent caterpillar, as a pest due to the abundant web-like nests and high densities that can rapidly defoliate trees in the cherry and apple family including plums. Most trees can recover and produce a new crop of leaves, and the tent caterpillars provide a nutritious food source for birds like black and yellow-billed cuckoos.
A close-up of the ‘Bird-poop moth’, Eucosma giganteana, a Silphium specialist restricted to prairies, including restorations. Photo by Kyle Johnson
Kyle’s highlight was identifying two new species that he has not seen before, which is quite a feat for someone who has been catching moths and butterflies since he was five. Although it will be winter before Kyle’s report is complete, he predicts that this survey will add 100 new species of moths to the Goose Pond list. Moths fly every month of the year (yes, even January), so this June survey only captures a small portion of the species present at Goose Pond. Kyle suspects there are 900 to 1,000 moth species at Goose Pond Sanctuary.
Goose Pond volunteer, Jim Otto sums up the night well:
“It was a wonderful night to be out at the Goose Pond Sanctuary prairies to participate in the moth survey. The weather was nice, and fireflies were out. I was amazed how Angus and Kyle were able to identify moths by sight. The moths seen ranged in size from “micro-moths” which were not much larger than a mosquito, to the Achemon sphinx, which had a wingspan of almost four inches. The Achemon sphinx moth was my favorite of the moths observed. It arrived at our survey location north of the Browne Prairie bench just before 10:00 pm, landing first on my shirt, then moving over to the light and sheet setup where it remained for the better part of an hour.”
Jim Otto’s favorite moth of the night, Achemon sphinx, hanging on the sheet by the Browne prairie bench with caddisflies. Photo by Jim Otto
So we’ve got a lot of species of moths. What are the implications? Disturbance, mainly prescribed fire, is a key component to maintaining prairie ecosystems. Fire maintains prairies, but kills a very high percentage of invertebrates. Burning an area entirely without refugia (small unburned patches) is “the worst thing you can do” for invertebrate populations, especially those without wings. Most of our prairies are burned every two to four years, though a few haven’t been burned in seven or eight years. We will continue to leave places unburned for several years to retain our strong moth diversity along with birds like Henslow's Sparrows and Sedge Wrens, and we’ll consider a higher degree of variation of our intentional disturbance in the future.
Pyrausta signatalis, a moth particularly fond of sandy habitats; occurs in a variety of prairies, but is not restricted to them. Photo by Kyle Johnson
Thank you to Kyle and Angus for your enthusiasm, expertise, and patience to respond to, “what moth is this?”, even when we asked about the same species 5+ times! We would also like to thank volunteers, Jim Otto, Maggie and Bob Honig, Miles Roth, Calla Norris, and Seth Steinhauer for joining us for the survey and providing excellent photos!
Written by Emma Raasch,Goose Pond Staff; Graham Steinhauer, Land Steward; and Mark Martin Co-resident Manager
