It’s Christmas Eve, so today’s Friday 5 will have a winter theme! If you live somewhere outside of the southernmost parts of the United States like I do, you have probably been experiencing some real winter weather. This usually means that the insects have hunkered down for the winter and very few things are active. However, there are several insects that are still active even when it’s close to zero degrees and the ground is covered with several feet of snow! These are 5 insects that you could see running around on top of the snow on a white Christmas, assuming you live in the areas where they are found:
Rock crawler. Image by Alex Wild, from myrmecos.net
1. Rock crawlers. Grylloblattodea is a funky order of insects that contains very few, highly specialized species. These insects are very well suited to living on snow and have all sorts of adaptations that allow them to do so. In fact, they are typically only found at very high elevations, high latitudes, or on glaciers! These insects are scavengers that run around on top of the snow and collect aerial plankton that is swept into their cold habitats on the wind. Few people even know these insects exist, let alone have actually seen one. Want to see them in action? There’s a great, short video on YouTube created by a rock crawler researcher that’s definitely worth watching!
Small winter stonefly (family Capniidae). Photo by Tom Eisele and from http://bugguide.net/node/view/175731.
2. Winter stoneflies. Stoneflies in at least two families (Capniidae and Taeniopterygidae) have adults that actually emerge in the winter and are commonly seen on top of the snow. Unlike most of the other insects in this post, these insects actually have wings. Whether they fly around on very cold days is an entirely different matter though. These are cold blooded animals after all, and insect wing muscles require a certain amount of heat to function. If they can’t warm up their wing muscles, they can’t fly! But even if they can’t fly, there are certain advantages to being an insect that emerges in the winter. Probably the most important is related the fact that very few animals are active outdoors when it’s very cold, including many animals that might like to eat a sluggish insect that can’t warm it’s wing muscles up enough to fly.
Snow fly (Family Limoniidae, Genus Chionea). Photo by Cosmin Manci, from http://iz.carnegiemnh.org/cranefly/limoniinae.htm.
3. Snow flies. Snow flies are close relatives of the crane flies and are active during the winter. They are wingless, though like all flies they do exhibit halteres. These flies run around on the snow and have been observed sucking the snow with their mouthparts to drink. Like their crane fly relatives, they are not thought to feed.
Snow scorpionfly. Photo by Stephen Luk, from http://bugguide.net/node/view/169476/bgimage.
4. Snow scorpionflies. Like the rock crawlers, I would dearly love to see one of these wingless scorpionflies on the snow! These insects belong to the order Mecoptera, though, unlike the rock crawlers, the entire order is not adapted for life in cold weather. Instead, there are just a handful of species within the family Boreidae that survive well on the snow. But those species need the cold weather. Supposedly, the heat from your hand is enough to kill one of these bugs!
Snow flea. Photo from http://www.wild-facts.com/wild-fact-846-fleas-in-the-winter-snow-fleas/
5. Snow Fleas. These aren’t technically insects, even though they have 6 legs, and therefore aren’t real fleas. However, they are hexapods, so they’re very closely related. Snow fleas are members of the order Collembola, the springtails. The snow fleas are quite active, sometimes in very large numbers, during sunny winter days and look like pepper on the snow. Though it’s not exactly known what these creatures do on top of the snow, they’re thought to be eating algae that grows on the surface of the snow. How’s that for specialized?!
There you have it! If you’re out and about on a sunny white Christmas in the northern parts of North America, keep an eye out for these insects running across the snow!
I wish all of my readers who celebrate Christmas a very happy holiday. And to the rest of you, I wish you a happy winter!
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The Dragonfly Woman 
Very cool! I knew about snow fleas and snow flies, but the others are new for me. And the heat from a hand is enough to kill some snow scorpionflies? Wow. That’s sensitive.
I admit I love cold weather and wintry precipitation, but living in Texas affords me a good trade for milder winters: plenty of critters active right through the season. I figure if I can’t have snow, I can at least have a variety of wildlife to watch.
I wholeheartedly agree with you about living in a warmer climate! However, I always have a hard time getting in the mood for Christmas in AZ because it’s just not cold. I spent most of my memorable childhood Christmases in Colorado, so it’s supposed to be cold at Christmas darn it! (Or at least less than 60 degrees.) The trade offs are great though – being able to get into streams all winter, seeing insects in the middle of January, and not having to drive in the snow.
Greetings from Florida, where I have lived 38 years and have never once seen snow. You just had to go and make a post about all the neat animals I’ll never get to see, didn’t you? : – )
If it makes you feel any better, I don’t get to see them in southern Arizona either! It does snow here on occasion, but I am pretty sure it’s only stuck to the ground 4 times since I was born. However, that doesn’t keep me from yelling “It’s snowing! It’s snowing!” every year when we get our 10 flakes falling out of the sky. :)
The snow insects are so interesting I had to do a post about them. Perhaps you should consider this post inspiration to travel to a place where you could actually see these insects? If you’re like me, you’ll go running screaming back home to warm back up after a few days!
Well, I was in Kentucky a few weeks back, but it didn’t snow.
But Florida has some neat bugs, so I’ll just have to be happy with what I can find instead of what I can’t.
That’s a great attitude! And you do have some fabulous bugs in Florida. I bought a book on the big bugs in Florida when I was there a few years ago and there are some really excellent insects in there! Granted, I didn’t get to see that many in real life, but I was there at the wrong time of year too.