Thursday, September 18, 2014

Of two-tailed bugs, absent salamanders, and flipped rocks

Well, we've gone out and flipped our rocks (or not - one of us cheated took an alternate approach.)

It has been a quiet year, probably because I forgot last year, and we lost momentum. In spite of that, we made some interesting finds.

VERY IMPORTANT UPDATE: I just checked Twitter; there are a bunch more Rock Flippers over there. I'll add them to the list in a new post.

Here is the lineup, as it is now, copied from Heather's blog, At the Edge of the Ordinary:

Over in the International Rock Flipping Day Flickr group, many more interesting things have been discovered:

And this was a handy tip: Heather had found a pillbug under one of her rocks. "Or maybe a sowbug," she said; she finds them confusing. So do I, unless I pick them up; pillbugs roll themselves into a ball; sowbugs don't. (Here's a sample pillbug.)

But Sara Rall, in the comments on Heather's post, gave us a quick way to tell the difference, even from a photo.

To tell a pill bug (which can roll up) from a sowbug (which can’t), look at the back end. If it has two “tails” that stick out you have a sowbug (which would be my guess in the photo, but I can’t really see well enough to be certain).

Here's a family of sowbugs I found under a paving stone next door:

"Two-tailed" woodlice, aka sowbugs.

Zooming in. See the tails?

BugGuide has a photo of pillbugs side-by-side with a sowbug for comparison.

Thanks, Sara!

As usual, there were a couple or more Rock Flippers who did the "work" but didn't pass on their findings. If you're one of them, either Heather or I would be happy to add your name to the list; just give us a shout.

And many thanks to Heather for hosting this year. And I hope it rains soon and she finds a salamander; she well deserves it!


  1. I love rock flipping day, in part because people find classes and even subphyla of critters that they've never encountered before.

    The "centipede" Paul Fehringer found is a polydesmid millipede (you can see the two pairs of legs per body segment that makes it a millipede, and the flattened shape with sort of "winged" edges over the legs (and pretty colors) make it a polydesmid.

    The "springtail" Rob Cruikshank found is actually a paurupodan. You can see 7 legs on one side, which rules out springtails (they are actual insects with only 3 legs per side). The short antennae and rounded back end are and easy way to distinguish it from the symphulans and centipedes it resembles.

    Love these things!

  2. Thanks! I passed on your comments to Paul and Rob on the Flickr pool.

  3. I was sort of wondering about that flat millipede.


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