Sunday, September 7, 2008

Did you "Flip A Rock" today?

Today is International Rock Flipping Day. In celebration, I went outside to flip a rock and see what lived beneath.

Here is the rock, in situ (in place), at the edge of my pond in southwest Ohio:

When I flipped it over, the first thing I saw were two aquatic "bugs" on the underside of the rock. (One crawled away before I could take the picture.) They reminded me of pill bugs (woodlice, sowbugs, "rolly pollies," pick your local nickname) so I assume they are an aquatic form of this crustacean. The head is green and the body a purplish-brown. My macro function isn't too great, so enlarging this picture will just get you an out-of-focus view, but if anybody can ID this critter, I would appreciate it.

[Edit: In looking more closely, I see legs.
I now realize this is insect-like, not an isopod.]

As I started to replace the rock, I saw something moving. At first, I thought it was a bit of plant matter, twirling in the residual vortex created when I flipped the rock, but then I realized it had purposeful movement.

Here is the thing enlarged.

I even got a little video clip of the grub-thing in action.

It made me think of a warble, the larval form of the rabbit botfly Cuterebra, which I sometimes see in cats. Does anyone know what this "water grub" might be?

[Edit: Thanks to a comment by Cestoady, I have ID'd the grub-thing. While researching the suggestion of tipulid, or Crane-fly larvae, I found it on What's That Bug? (5th image as you scroll down) It is the larva of a horsefly, which I have in abundance here since the Purple Martins left. Good thing I didn't try to touch it - they bite, injecting a toxin which causes extreme and prolonged pain and swelling, according to this entry at Bug Guide.]

If you would like to participate in the second annual International Rock Flipping Day, please click here for the guidelines. Then, go flip over a rock and see what you can find. Come back and share your observations with the rest of us, by posting your link in the comments section or by sending a link to your post to Dave.

Don't forget to put the rock back!


Here's a list of recent rock-flipping sites to visit:

Pohanginapete (Pohangina Valley, Aotearoa/New Zealand)
Blaugustine (London, England)
Nature Remains (Ohio, USA)
Pensacola Daily Photo (Florida, USA)
KatDoc’s World (Ohio, USA)
Notes from the Cloud Messenger (Ontario, Canada)
Brittle Road (Texas [?])
Sherry Chandler (Kentucky, USA)
osage + orange (Illinois, USA)
Rock Paper Lizard (British Columbia, Canada)
The Crafty H (Virginia, USA)
Chicken Spaghetti (Connecticut, USA)
A Passion for Nature (New York, USA)
The Dog Geek (Virginia, USA)
Blue Ridge blog (North Carolina, USA)
Bug Girl’s Blog (Michigan, USA)
chatoyance (Austin, Texas)
Riverside Rambles (Missouri, USA)
Pines Above Snow(Maryland, USA)
Beth’s stories (Maine, USA)
A Honey of an Anklet (Virginia, USA)
Wanderin’ Weeta (British Columbia, Canada)
Fate, Felicity, or Fluke (Oregon, USA)
The Northwest Nature Nut (Oregon, USA)
Roundrock Journal (Missouri, USA)
The New Dharma Bums (California, USA)
The Marvelous in Nature (Ontario, Canada)
Via Negativa (Pennsylvania, USA)
Mrs. Gray’s class, Beatty-Warren Middle School (Pennsylvania, USA)
Cicero Sings (British Columbia, Canada)
Pocahontas County Fair (West Virginia, USA)
Let’s Paint Nature (Illinois, USA)
Sleeping in the Heartland (Midwestern U.S.)
Three Oaks (Ohio, USA)


cestoady said...

Hi, I saw your comment on Nature Remains so took a peek at your site.

That "water grub" reminds me of a tipulid or Crane fly larva that matures into the familiar flies that look like hugh mosquitoes. Check it out .

Deborah Godin said...

Amazing - a whole little world under that unassuming rock...but then I guess that's the whole point of IRFD! Enjoyed you post.

Lynne said...

I forgot to flip a rock today. It's such a fun idea I might just have to do it later.
I have to say that I get totally creeped out at the mention of botfly larvae.

Dog_geek said...

Looks like you picked a good rock to flip! Buyt, horsefly larvae - yikes!

Jen said...

Well I was thinking you found something very cool until you said horsefly. I know they have their place in the world, but I hate them sooooo much. Glad you didn't touch it, but part of me wants you to go back and find something to feed it to so it won't grow up and make more. Beautiful pictures, thanks for sharing your flip with us!

Susan T. said...

Oooh, I like that larva pic. Very neat. I need to learn to get closeup shots like that!

Susan Gets Native said...


PJ said...

I really enjoyed this scientific narrative. Each rock flip is so different and so interesting.

Mary said...


If I had not been hiding under a rock, I would have participated. I love flipping rocks around the pond!

The horsefly...they bite, injecting a toxin which causes extreme and prolonged pain and swelling," Yikes. I tend to touch what I find...

Thanks for not lecturing me on serving rawhides...



KatDoc said...

I know the rules of IRFD say to put the rock back gently, so as not to disturb the natives, but when I found out the grub-thing was a horsefly larva, I was tempted to go back out and SMASH the rock down.

if horseflies (and their larvae) have a useful place in nature, I don't know what it would be.


pohanginapete said...

Kathi, that's a cool horse fly larva. I might be wrong, but I doubt you were at any risk from the larva — it's the adult flies that bite. However, the larvae are predatory so they might be able to bite humans, although I suspect you'd have to work hard to get them to do so. We have tabanids (horse flies) here in New Zealand, but the adults feed on nectar; on the other hand, I've been bitten by spectacular horse flies in Mongolia, and I can confirm that it hurts!

KatDoc said...

Thanks, Pete, for traveling all the way from New Zealand to visit my blog. I have been bitten by many a horsefly (so have my horses!) and I agree that it hurts, but according to what I read on "" the larvae bite, too! They are carnivorous, and they inject a substance from their salivary glands that paralyzes their prey. Two people reported being bitten and said it is very intense, and that the pain and swelling lasted for 18 hours to 3 days.

I don't care to find out! (shiver)