Pectinate grooming apparatus on flying ant

rjlittlefield · Post by **rjlittlefield** » Wed Jul 04, 2007 10:59 pm

In my previous post about the flying ants, we got to discussing the "long sharp spur" sticking down from the middle of the ant's front leg. These spurs are used for grooming, but from what can be seen in the earlier post, it's not obvious how that might work. From casual examination at low power, I had thought that the spur was merely thickened. Not so!

At much higher magnification the pectinate (comb like) structure becomes evident. With more detail showing, it's now pretty easy to imagine antennae being brushed clean as they get dragged through that curved gap between the spur and the first joint of the tarsus, where the matching comb is.

Shown here at about 400X on your monitor...

I confess, I find it difficult and tedious to adjust the subject pose and illumination with these high magnification stacks. The problem is, I can't tell exactly what I'm going to get by looking through the DSLR eyepiece -- because all I can see is one slice at a time! So I do the best I can by rocking the focus back and forth while playing with the lights, but I'm often surprised by what the stacked composite looks like. I'm not entirely happy with the illumination in these two shots, but I ran out of time to play with it, so these are what we get.

Hope you like 'em!

--Rik

Technical: Canon 300D with 20X NA 0.40 achromat objective on 150mm extension, stacked using Helicon Focus at 4-5 micron steps (6 or 7 steps per 0.001"). Dual fiber halogen illuminator with Kleenex tissue diffuser.

Planapo · Post by **Planapo** » Wed Jul 04, 2007 11:34 pm

Rik, I am delighted how you´ve documented the cleaning apparatus.

One picture says more than a thousand words, especially when it has been photographed as perfectly as yours! Hence now all know what we were talking about in your previous post.

Best regards,
Betty

Gordon C. Snelling · Post by **Gordon C. Snelling** » Thu Jul 05, 2007 5:24 am

Beautiful

rjlittlefield · Post by **rjlittlefield** » Thu Jul 05, 2007 1:26 pm

Betty and Gordon, thanks for the compliments. It is nice to know that somebody besides myself likes these pictures!

Here's an interesting question posed by a colleague at work:

How big is this structure, compared to individual cells?

From the photos, it looks like the bristle spacing in the combs is around 8 microns.

If I read correctly, that's about the same as the diameter of a human red blood cell. I might speculate that each of those bristles is formed by a single cell, but of course such speculation is much more often wrong than right!

Do either of you know what the right answer is? How does the size of the comb structure correspond to the cells that form it?

Thanks much!

--Rik

beetleman · Post by **beetleman** » Thu Jul 05, 2007 3:06 pm

Wait a minute, Wait a minute. I think these pictures are awesome also

Incredible comes to mind too. Now what I want to know is "are they flexible or rigid" Pure science here.

Mike B in OKlahoma · Post by **Mike B in OKlahoma** » Thu Jul 05, 2007 3:56 pm

Rik, these are amazing!

It looks like the ant has some sort of fluid being held between the fibers of the "cleaner" somewhat like tap water stuck between teeth of a comb. Or is that something else entirely?

rjlittlefield · Post by **rjlittlefield** » Thu Jul 05, 2007 6:54 pm

beetleman wrote:Wait a minute, Wait a minute. I think these pictures are awesome also

Hhmm, somehow what I wrote didn't come out exactly as I intended.

Well, it's not the first time that has happened!

Moving on... Questions, you got questions.

are they flexible or rigid

...some sort of fluid..."

Hah, you guys are good! At the moment, I don't have a clue, but it'll be fun trying to find out.

I guess my expectation is that those teeth on the comb would be about as flexible as bristles of the same size. That means they'll be stiff in comparison to the floppiness of the joint in a dead specimen (the joint will flex before the tooth bends), but capable of being bent quite a bit without damage -- like deflection at the end that's several times their average diameter. How to relate that to the strength of the ant -- do they bend in use? -- now, that's a tricky question!

About the appearance of liquid, I agree, the images sure do look like it. But that specimen had not been exposed to any liquids or vapors other than air, and had also been exposed to warm dry air for quite a while before the pictures were taken. So if it is liquid, all I could guess would be some kind of oil. It's easy to be misled, however, by transparent structures at these magnifications. Sometimes a bit of overlap can look just like fluid merging of the structures. I'll see if I can figure it out from some other specimens. At the moment, I'm inclined to think it's just the visual appearance of overlap.

--Rik

Mike B in OKlahoma · Post by **Mike B in OKlahoma** » Thu Jul 05, 2007 7:03 pm

My earlier viewing was done on a monitor at work. Looking at these on my better home monitor, I think the appearance of fluid is a change in the thickness/nature of the grooming bristles. But not positive of that.

rjlittlefield · Post by **rjlittlefield** » Thu Jul 05, 2007 9:44 pm

And the answer is...

They're dry and flexible.

See followup posting in the Micro forum.

--Rik

Ken Ramos · Post by **Ken Ramos** » Fri Jul 06, 2007 7:39 am

Geez...I'm really late in getting to this post, look at all those replies.

Well all I was going to say is that I like these much better than those over the shoulder, panic stricken ones.

Much more detailed too!

Sven Bernert · Post by **Sven Bernert** » Sat Jul 07, 2007 5:49 am

I'm with Ken!

Rik, very cool stuff technically.

Sven