Masked Biologist: Fireflies In The Northwoods

Jun 22, 2020

The Masked Biologist saw a firefly recently, and it “sparked” an idea that turned into this week’s episode of Wildlife Matters.

I saw a firefly a couple of days ago. This may sound unremarkable to you. This is the start of our firefly season, so maybe you see fireflies regularly. Then again, maybe you can’t remember the last time you saw a firefly and you haven’t really thought about it. In this case, it was a sunny afternoon, and I was on a business call when I happened to look out the dining room window and spy a firefly walking across the window screen.

At first I admit, even though I saw and identified it, I didn’t give it a lot of thought. But now as I think back, I don’t remember the last time I saw a firefly here at my house. This is good news for me; it means my rain garden and my efforts to enhance my yard for wildlife are starting to bear fruit.

The Ojibwa word for firefly is waawaatesi, and it plays a vey important role in their culture. According to tradition, white-tailed deer, or waawaashkeshi are ready for harvest when waawaatesiwag begin making small sparks in the night air. You might note that the names for deer and firefly both start similarly, with waawaa – this is a kind of word picture involving a white flash or a flash of light, which you see when an alarmed deer run away with its tail up or when you see fireflies blinking in the grass at night. As we see our winters moderate and shorten, this will have impacts on the fawn drop, the emergence of fireflies and the Chippewa deer harvest.

Fireflies (or lightning bugs) are actually beetles. There is not just one kind of firefly – there could be two to three hundred species in the United States alone. Our most ubiquitous firefly (in Wisconsin and across the country) is Photinus pyralis, which also goes by “common Eastern firefly” or “the big dipper firefly.” They live for 1-2 years as larvae, sort of a grub, but then take on the adult form to breed. As adults, they may only live 5-30 days. They are carnivores, feeding on soft-bodied insects, worms, snails and slugs. Some fireflies feed as both larvae and adults, but the big dipper feeds only as a larva. So they become an adult, blink, breed, reproduce, and die in the span of a month or less. They get the name big dipper from the flight-flash behavior of the adult male, which makes a sort of lighted upswing “J” in flight, looking a bit like a ladle or dipper. Plus, you know…stars. The females don’t fly. They watch the males fly and flash, and they blink from vegetation, inviting them to land and make magic. The glow they produce is bright for a biochemical reaction, putting out about 1/40th candlepower. However, it is difficult for them to compete with the lights in town, which is part of why I was pleasantly surprised to see a firefly here on one of the three busiest streets in Rhinelander.

Sadly, fireflies are facing a dim future without help. You can go to the website Firefly.org to learn a lot more about these amazing insects. You can read about how to encourage fireflies to take up residence in your yard, and species to plant to benefit them. Install water features in your garden. Keep some mud, leaf litter, or a decaying log in damp soil for the larvae to occupy. Mow your grass tall, don’t use insecticides, and don’t rake up all the leaves right away in fall. Plant native trees and grasses and have some nice dark corners in your yard for the adults to signal and find each other.

If it has been too long since you have seen fireflies, I suggest you head toward the Rhinelander soccer fields or the fence around the airport. Those areas have all the ingredients for prime firefly habitat, and I know my wife and I like to take a drive on a summer night just to keep our own internal lights lit, remembering childhood summer nights filled with darting and blinking fireflies. Make sure you keep a place in your life, in your summer, for the role of the firefly and maybe together we can continue to make a difference for these and other insects before it is too late.