What Are Snow Fleas?

Mar 27, 2019

A Snow Flea with anti-freeze activated.
Credit Wikimedia Commons Plantman2

We're continuing our Curious North series today with a listener question about something you may or may not have heard of.

An anonymous listener in the Rhinelander area recently asked: What are snow fleas? Where do they live and what do they eat?

Ken Krall relayed the questioned to P.J.Liesch. Here's their conversation...

"I'm P.J. Liesch, (UW) Extension emtomologist and Director of the UW-Madison insect diagnostic lab. "

Krall: "Someone came up with a question about snow fleas, so tell us what they are..."

PJL:"You might have noticed them before. Maybe you were out cross-country skiing and snowshoeing and it's about a millimeter long dark creature you can see out on the snow. They're found in large numbers and they're a relative of insects...commonly called spring ails. They get the name spring tails because they have a little structure on their bodies that works like a spring-loaded Pogo stick that allows them to jump around. If you look at them closely, they look like flakes of pepper that someone dumped out on the snow. They're about to bounce and jump and move around."

Krall:"They're one of the few creatures up here visible in the winter, right?"

PJL: One thing about snow fleas is they are really present year-round. With the snow on the ground they really stand out with the contasting colors. These creatures are typically found in damp areas and feed on decomposing stuff, fungal spores and stuff like that. They're around year-round, but with the snow on the ground. They're really well adapted to our cold conditions in the winter months."

Krall: "Tell us what their (role) in the eco-system is..."

PJL: "...they help break stuff down in the environment. If you went out in the forest and just took a scoop of leaf litter and other plant materials and took a look at that you'd be amazed at the sheer number of creatures you would find. Snow fleas and other types of springtails. There might be mites...and other types of beetles and other insect. There is this microscoping, nearly invisible community beneath our feet when you go out into the woods. Springtails play an important role in that as they help break stuff down. They, themselves. are serving as a food source for tiny predators. They're part of the tiny ecosystem beneath your feet going on out in the woods."

Krall:"..and common, I assume, in the Upper Midwest area..."

PJL:"Springtails are extremely common. If you sifted through that soil you would undoubtedly find some of these. You can find them in rich soil, decomposing leaves, rotting logs. fungi and things like that. You're going to find some of these Springtails close by. When it comes to winter survival, these snow fleas have a really 'cool' adaptation. The reason we don't have many creatures active in the winter months is they're at risk of freezing to death. Snow fleas have an adaptation. They make their own natural anti-freeze molecules that are a type of protein in their body. That prevents them from freezing and that allows them to be active at some surprisingly low temperatures. I've seen them when I was cross-country skiing in the high single digits. They have some unique  adaptations that allow them to be active at some surprisingly cold temperatures."

UW-Extension entomologist P.J. Liesch with Ken Krall.

This story is a part of our listener question series, Curious North. Submit your own Curious North questions below. Your question may be featured in a future story.

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