A Water Bug - Identification Help Appreciated

Walter Piorkowski · Post by **Walter Piorkowski** » Wed Sep 03, 2008 8:48 pm

Images 1 through 3
35mm Canon Macro lens at f/8 to f/11, one 30mm tube
Horizontal F.O.V. 9.0 mm
Image 1 dual reflected and transmitted illumination
Images2 and 3 reflected illumination

Canon 10D
Photoshop processing

This photogenic little bug was found in my local pond. It hangs upside down just below the waters surface. I found unexpectedly that it likes to eat insect larvae when I added one to the watch glass it was in. It pounced upon it so fast the larvae was knocked clear out of my field of view.

Walt

rjlittlefield · Post by **rjlittlefield** » Wed Sep 03, 2008 9:24 pm

Looks to me like a "Backswimmer", one of the true bugs, family Notonectidae.

They're aggressive little guys, liable to take a chomp out of you too.

I especially like images 2 and 3. Excellent capture of those fine filaments on the side of the abdomen. I have no idea what those do -- never noticed them before I saw these images, but now I see them in some of the BugGuide shots too.

--Rik

lauriek · Post by **lauriek** » Thu Sep 04, 2008 6:13 am

Over here we call these guys "Water boatmen", I think because it looks like they are paddling oars...

Harold Gough · Post by **Harold Gough** » Thu Sep 04, 2008 6:38 am

The genus Corixa swims the other way up (back uppermost) and its, rear, swimming legs are not so elongated, being of similar length to the middle pair. The UK species is C. punctata, the Lesser Water Boatman.

Harold

P_T · Post by **P_T** » Thu Sep 04, 2008 6:54 am

Oh wow, that is a funky little fella there!! How big is it?

Walter Piorkowski · Post by **Walter Piorkowski** » Thu Sep 04, 2008 10:34 am

Thank you gentlemen for your help and knowledge. The term boatman does stir some old memoeries of that title being given to this subject. P_T, I try on most of my images to put a horizontal field of view or FOV size to help with this type of problem. To answer, maybe 7mm "leg tip to leg tip.
Walt

NikonUser · Post by **NikonUser** » Thu Sep 04, 2008 11:02 am

rjlittlefield wrote: Excellent capture of those fine filaments on the side of the abdomen. I have no idea what those do -- never noticed them before I saw these images, but now I see them in some of the BugGuide shots too.

--Rik

I believe these are hydrofuge hairs and function to hold the bug on the surface while it takes in a bubble of air; all part of its physical gill and plastron respiration.

Harold Gough · Post by **Harold Gough** » Thu Sep 04, 2008 11:27 pm

Such long, fine filaments (setae or hairs), in aquatic arthropods generally have the function of supporting the insect on/under the surface film of the water by using the surface tension.

Harold