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3. Tiny Stoneflies?

I walked a few lesser know Steelhead streams today checking water levels and temps. The Steelhead haven't poured into the smaller streams here yet. BUT! I noticed bugs are really starting to show themselves everywhere I looked. I found these curious little insects that appeared to look like puny stoneflies. They were incredibly small! I could put about 20 of them on my thumbnail and not cover it. I was wondering if anyone knew what they might be.

Hi Jim,

You are right, they are very tiny stoneflies. They look to be Allocapnia, probably pygmaea (Little Black Snowfly). The males are brachypterous (short winged) like this. I bet they probably looked black to the naked eye. Notice how under magnification their true Dk. chocolate brown color is revealed?

BTW, nice photos. The female's setting is pretty cool.:) Too bad there seems to be a little moisture on a part of the lense or something. Such are the limitations of inclement weather photography.

Regards,

Kurt, would you rule out Allocapnia minima ?

No, it very well could be. It's hard to rule out a number of species definitively working with just these photos alone. Based on how many Jim said he could get on his thumbnail, pygmaea is the logical choice. A. minima is small as well, though reportedly not nearly as populous. It is also usually a little lighter (or more obvious) brown, sometimes even amber at the thoracic margins and on some of the terga as in this photo http://bugguide.net/node/view/506620
But, even this is not a rule.

Actually it was the size that got me to wondering, because when I compared all the adult pictures between minima and pygmaea here:
http://bugguide.net/node/view/39481/bgpage I noticed very little difference in the size as stated. Both, depending on the pictures, showed variation in color and depicted resemblances in the thoracic margins and terga.

P.S. Sorry Kurt, we got caught between my post and your PM.

Aggh! We were posting at the same time. You are absolutely right, Al. Minima is also tiny and color doesn't seem to be a very dependable character. I was hoping to edit my post before you saw it, but I was too slow.:)

Thanks for your input guys. You're a huge help. I couldn't BELIEVE how tiny they were. I couldn't get my camera to stay in macro they (and I) were scrambling around. Are these the smallest of the stones? I have sharp eyes (especially to movement) and noticed one on a rock by the water line. I looked along the shore for more and found them in good numbers in certain areas. You can see the hair on my arm where I put on one my skin for better contrast.(Or so I thought)

My camera takes some abuse... I must admit.

Thanks again you guys!

If that first one had been in a little sharper focus, we're talking award winning in my book. With everything a guide has to do, you must be commended for grabbing photos like this of something so tiny in weather. Kudos!!

Jim,

For your stream lore file, Allocapnia pygmaea is incredibly abundant on many of your streams. Some studies mention that their numbers can be so great that they can outnumber all other species with the possible exception of some midges or black flies. One of the reasons they show up so infrequently in angler stream samples is because they live really deep in the substrate most of the year, sometimes measured in feet not inches! They can hatch well into the spring, and many people running into swarms of them along the banks mistake them for forest termites or ants that they closely resemble.

@ Entoman, this is one of the main reasons I love this forum. You fine fellows possess such a wealth of knowledge and are willing to help someone like myself.

I did have some slight film on the lens of my camera. I will need it charged and clean for another day of Steelheading tomorrow.

As I was saying, I couldn't believe their size. I checked out the links you provided above. That definitely is the bug in question. I had one on me at first but he fell off. It almost looked like a tiny duck louse at first glance, but upon further investigation I could see he had some tell tale signs of a stonefly.

Don't go thanking me on my shoddy camera work now! Haha!

Once again, thanks for helping me out on my Entomology.

Ha! Flattery will get you everywhere.:)

BTW - if you are able to get a good closeup from the side and from overhead of the last 4 abdominal segs of the male (short wings), I'm pretty confident we can nail down the species with certainty as the two possibilities are pretty different there.

Al-

As luck would have it, DiscoverLife.org has the two species side by side
http://www.discoverlife.org/mp/20q?search=Allocapnia.

Comparing the wing venation of the females and the conformation of the males with each other and then against these specimens, I think they show pygmaea the better match. Let me know what you think.

pygmaea it is. Thanks for the link, I don't know how I missed it on my many searches, but it's bookmarked now.

Good work as usual Kurt.

Al-

Well, as the old saying goes,"I'd rather be lucky than good." :) Thank's for questioning my false color and size assumptions. It seems like we learn something new with every one of these. The collaboration we share is a big reason why this forum is so valuable & fun!