A while back Diane Anderson discovered this rare moth at her house and shared this picture with Cook County News-Herald readers. David MacLean, an expert in moths and butterflies, saw the picture and got in touch with Diane, who gave the moth to him. It turns out that Diane was right; it is a Black Witch moth, which has never been recorded in Cook County. But how did it get here? Did it ride on the antlers of a fast running deer then hop onto the back of a smooth swimming duck, hitchhiking its way on beasts and birds from the deep south to Cook County? Photo courtesy of Diane Anderson
Just what you have been wondering, right?
Sitting around the supper table, the question begged to be asked, “Just how many types of moths are there in Cook County anyway?” No answer. “Cat got your tongue?” I ask rhetorically to my cat.
To answer my question, I emailed David B. MacLean, Cook County’s resident moth expert. My interest in moths was piqued after Dianne Anderson sent in a picture of a Black Witch moth (Ascalapha Odorata), never seen before in Cook County. And, as it turns out, is only the 16th black witch moth ever recorded being cited in the state of Minnesota.
Dave offered up tons more information than my purring cat.
“There are 521 moth species in Cook County,” he replied.
Huh? Thinking back to my high school biology days, where I learned how to yodel and apparently not much else, I was coming up with six: little ones, little bit bigger ones, bigger still, bigger yet, really big and so big that they terrify you when they land on your light, and the room goes black. As for the colors of moths, in my not so scientific opinion, there are two colors, grey and almost grey.
Turns out David, who is a not very retired, retired lepidopterist entomologist, knows a few more things than either my cat or I know about moths.
Different types of moths live in various kinds of areas. David looks for moths in aspen-birchspruce fir dominated forests and openings. He finds the little winged creatures living in dry-mesic black spruce-jack-pine dominated woodland openings and searches for them on the Lake Superior shoreline. David finds moths in dry-mesic spruce-firaspen– birch dominated woodlands, wet meadows, rich peatlands, acid peatlands, in his back yard, pretty much everywhere, and everywhere he goes, David keeps an eye out for moths.
From 1988 to 2006, David recorded and reported in The Great Lakes Entomologist that he (and others) had found four hundred and sixty-five species of butterflies, skippers, and moths in Cook County.
In 2012, reporting in the Michigan Entomological Society newsletter, Dave and two other lepidopterists, Robert Dana and Kyle Johnson, added seven species of butterflies and skippers and 123 species of moths to the 2006 Cook County list.
Those new lepidopteron species by family additions included Hesperidae (3), Lycaenidae (1), Nymphalidae (3) Drepanidae (1), Geometridae (42), Sphingidae (1), Notodontidae (2), and Noctuidae (77).
Some of those specimens were caught and are housed in the Grand Portage Monument. Some are now in David’s private collection. Others have been preserved in the University of Wisconsin Insect Research Collection, with some duplicates in the University of Minnesota Entomology Collection.
Those 2012 additions brought the number of butterflies and skipper species reported from Cook County to 73 and the number of moth species to 521.
This latest addition by Diane Anderson, who agreed to share her find with Dave, will make it 522.
But how did the Black Witch moth get to Cook County? The Black Witch range is from Brazil to the southern United States.
To answer that, Dave looked to the weather and sent this reply to Diane.
“In preparing my 2019 Cook County, Minnesota Seasonal Summary for the Lepidopterists Society, I have looked into weather conditions that might have helped carry your (Diane’s) Black Witch specimen which found its way from, who knows where, to your home in Hovland. Perfect for Halloween, don’t you think?
“I was able to access data from the NOAA Duluth Airport online for October 2 and 3, 2019. On Wednesday, October 2, the barometric pressure in Duluth was falling and reached 25.54 in. by midnight. Wind speed ranged from 8-21 mph with gusts from 22-36 mph. A stormy and windy day to be sure with wind mainly out of the East after 10 a.m.”
On Thursday, Wednesday, 3 (the day Diane discovered the moth), barometric pressure continued to fall and reached 28.48 in by 10 a.m. after which pressure rose to 28.81 by midnight. Wind continued out of the East, northeast until 10 a.m. at 17-8 mph.
“My reason for doing this is to provide evidence that a large low pressure system over northeastern Minnesota with strong winds out of the East played a role in carrying the Black Witch from the far south up the East Coast and over Lake Superior to your house in Hovland. Certainly not proof, but If Ascalapha Odorata can get all the way to Hawaii, why not Hovland? Your record of the Black Witch is only the 16th from Minnesota and the first from Cook County. Entomology Rocks. Congratulations, Dave.
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