Quinquennial Snow Flea Session

After my “In Search of Snow Bugs” post a few days ago, Lang Elliott asked if I had any great pictures of snow fleas. I checked my files, and I found that my last attempt to photograph snow fleas on snow was the week I got my Canon macro lens, five years ago (I do have several shots of them on other substrates, like the group I found under bark this past December).  Those pictures are decidedly not great. Snow fleas on snow are about the most difficult things to photograph, because in addition to their being only about 1.5 mm long and jumping out of sight as soon as I find them in the viewfinder, photographing a dark object on a bright white background inevitably results in an underexposed subject or an overexposed background. Plus, with the blindingly bright snow on a sunny day, I can never be sure how the pictures are coming out when I review them on the LCD. But, since it was so nice out the other day, I decided to kneel in the snow for an hour and a half in a group of snow fleas and see what I could come up with. The results are still not exactly great, but possibly the best that can be done with this combination of camera, lens, subject, and photographer. Possibly if I had a better photo editing program I could create the illusion that I had taken great photos. Anyway, here are some of my favorites, out of the 300 or so I had to choose from. IMG_0419 IMG_0421 IMG_0438  IMG_0448 IMG_0464 IMG_0556  IMG_0356


In the photo above, you may recognize yesterday’s mystery object:


It turns out that when a snow flea is getting ready to jump, it everts these three sticky vesicles from its anus, which help keep it from bouncing around when it lands. Another interesting feature in the above shot is the pair of dorsal spines. Their relatively large size indicates that this not Hypogastrura nivicola, the common species that snow fleas are usually assumed to be. It is probably H. harveyi, but I still need to run these photos by Frans Janssens to verify that. In addition to the size of the anal spines, snow flea identification requires examining the number and arrangement of setae (hairs) in various places, e.g. above the eyes and on the fourth abdominal segment. These photos, while certainly not National Geographic quality, should suffice for that purpose.


This is the one photo I got that shows the furca, which is the “tail” with which snow fleas and other springtails do their “springing.” Five years ago I had managed a shot of a true H. nivicola (note the lack of prominent anal spines) that shows the furca a little better.


When I was just about done with my hour and a half of kneeling in the snow, I suddenly realized that the “baby snow fleas” I had been ignoring were actually a totally unrelated kind of springtail:

IMG_0490 IMG_0559 IMG_0567

As you can see, they came in a variety of colors, and I’m not certain they’re all the same kind, but it seems possible that they are. A quick look through BugGuide suggests the genus Proisotoma (Isotomidae), which belongs to a different order from snow fleas. I’ll update this post when I learn more. These were all around 1 mm long, or two-thirds the size of a snow flea.

Added 9/10/2015: Frans Janssens has identified the smaller ones as Vertagopus pseudocinereus (Isotomidae). He also confirmed that the long anal spines identify the snow fleas as Hypogastrura harveyi.  There are two other Nearctic species in the H. nivicola species group, both with much smaller spines. In H. tooliki the spines are placed on large papillae, and on H. nivicola they are not.

About Charley Eiseman

I am a freelance naturalist, endlessly fascinated by the interconnections of all the living and nonliving things around me. I am the lead author of Tracks & Sign of Insects and Other Invertebrates (Stackpole Books, 2010), and continue to collect photographs and information on this subject. These days I am especially drawn to galls, leaf mines, and other plant-insect interactions.
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15 Responses to Quinquennial Snow Flea Session

  1. I have often wondered about the color difference when I’ve seen patches of snow fleas, usually grey-blackish, but occasionally that reddish brown. Look forward to your conclusions.

  2. toadsong says:

    This is great beyond great! I am so jealous. Snowfleas are one of my all-time favorite critters, after seeing them in great numbers in the Adirondacks years ago, where they would fall into shoe prints and turn the snow black. At times I found great numbers of these springtails floating on water at the edge of ponds. And on one occasion I found a column marching through the woods like army ants. I only found them because i noticed a darkish line across a trail and realized it wasn’t a shadow. The column was about 1.5 inches wide and extended into the forest at least 15′ before breaking up into smaller columns. Ever heard of that? A column of countless marching (hopping) springtails?

    • No, I’ve never heard of such a thing! I’d love to see that. I’m also still waiting to find one of these columns of fungus gnat larvae.

      • toadsong says:

        I figured it was some kind of military maneuver, a lilliputian army of snowfleas preparing to attack a neighboring army.

        Did you know that if you put a lot of snow fleas in a tin can (along with some dry leaf fragments), you can put your ear to the can and hear the springtails hopping! I did this years ago in the Adirondacks, having scooped up a bunch from a boot-print in the snow, and then carefully herding them into the jar. I also viewed them under a spotting scope and learned quickly that they are exceedingly prone to drying up when the heat of a light is applied. They’re very delicate and need constant moisture.

        As I understand it, their appearance on snow is maladaptive, an accident having to do with moisture gradients. They come up through little micro-passageways and if the snow beings melting, the passageways disappear and they become stuck on top of the snow, where they will die. Is this the correct interpretation? I seriously doubt they actually want to be on top the snow, when their real livelihood is pursued in the leaf litter under the snow.

        • Sometimes when there isn’t snow, I can hear them like falling rain on the leaf litter.

          It may be true that they come up through micro-passageways… I was guessing that they mainly come up along stems and tree trunks, but it could well be that they do both. From what I can tell, you’re right that it doesn’t do them any good to be up on the snow. I’ve never seen them mating, or really doing anything other than just jumping around at random and accumulating in footprints and other depressions. After spending all that time with them the other day, I’m confident that they are unable to burrow down into snow (at least not dense snow on a warm day). They would start to wander into little mini-caves in the snow but would always get stuck and have to come back out.

          On the other hand, I don’t ever see masses of dead snow fleas lying on the snow. I don’t think I’ve seen even a single dead snow flea. So it’s a little mysterious what happens to them if they all die… I don’t think there are enough birds and spiders out there to make them all disappear. Maybe at some point somebody finds an exit and they all form a big column and file into it.

          Speaking of making snow fleas disappear: After hearing Lynn Rogers’ observations of bears lapping up snow fleas, I gave it a try one time when I found them congregating on sap dripping down a sugar maple. They’re very peppery!

  3. toadsong says:

    Great, great, great, great, great, great, great ……… !

  4. Kathie Fiveash says:

    Bravo! Do they have twice 7 or 8 eyes? I like their faces.

  5. Cassie Novak says:

    Seeing these guys on the snow during warm days is one of the ways I make it through a tough, long northern MN winter. They are a really wonderful ‘bug ambassador’ since they are so numerous, small and harmless.

  6. Chris Renna says:

    Totally amazing. Love the sticky landing gear.

  7. Russell Hopping says:

    Hi Charlie,

    This is great stuff!



    Russell Hopping
    Ecology Program Director

    The Trustees of Reservations
    113 Andover Street | North Andover, MA 01845
    rhopping@ttor.org | 978.840.4446 x1927 tel | 978.390.4218 cell

    Web: thetrustees.org | Facebook: facebook.com/thetrustees | Twitter: twitter.com/thetrustees

  8. lisa says:

    GREAT post! Made even greater by the questions and answers in the comments.

  9. Pingback: Specks in the Snow | Northeast Wilderness Trust

  10. Pingback: The Long-Lost Snow Fly | BugTracks

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