Ant milking aphids

Bruce Williams · Post by **Bruce Williams** » Wed Dec 06, 2006 7:57 am

Hi folks,

This is one of my first macro shots that I took back in April 2004 with my Fuji 6900z. The young stinging nettle had taken root in an old brick wall at about head height. The plant was absolutely covered in aphids, all busily feeding on its sap. There were quite a number of ants in attendance (as is usually the case, mostly on the inaccessible side of the plant). Anyway by "carefully" rearranging the stems a bit I managed to get a few close-up shots of the action.

The ants are "milking" the aphids by stroking them with their front legs and antennae. In response the aphids excrete a clear, nutrient rich substance calle honeydew -you can just make out a drop of honeydew in the ant's mandibles. It's a mutually advantageous arrangement as the ants help protect the aphids from other insect predators.

Anyone know why some of the aphids are light green and fat?

Bruce

Mike B in OKlahoma · Post by **Mike B in OKlahoma** » Wed Dec 06, 2006 5:57 pm

Good job for an early macro attempt. I suspect this shot would do well with some more USM, looks like perhaps you originally had it at a smaller size and "uprezzed" it?

The subject here is wonderful, one of the better scenes of this type I've seen. The masses of aphids are very cool.

Ken Ramos · Post by **Ken Ramos** » Wed Dec 06, 2006 6:26 pm

Bruce asked:

Anyone know why some of the aphids are light green and fat?

Maybe they came from a better or more affluent neighborhood?

I really don't know Bruce but a good question and a very good photograph.

beetleman · Post by **beetleman** » Wed Dec 06, 2006 8:17 pm

You probably "are what you eat" extends into the insect world also.

rjlittlefield · Post by **rjlittlefield** » Wed Dec 06, 2006 8:28 pm

Bruce,

I don't know a lot about aphids, but here are a couple of ideas. One possibility is that the large light green aphids have just grown to the limit of their skins, and they're either ready to molt or they've assumed adult coloration. Another possibility is that they've been parasitized and are on their way to becoming "mummies". See here and here for more about that possibility. I suppose there are other diseases and/or parasitoids that would look the same, but I don't know any details.

--Rik

Mike B in OKlahoma · Post by **Mike B in OKlahoma** » Wed Dec 06, 2006 8:48 pm

My guess would be they are two different species, but it may be something as simple as two different generations. Don't know much about aphids here.

Bruce Williams · Post by **Bruce Williams** » Thu Dec 07, 2006 10:34 am

Thanks for your comments guys.

Doug and Ken,

Rik, Thanks for the links - fascinating info and some nice pics too.

Mike, your suggestion re USM had me going back to check out the original image.

Having had another "play" on Photoshop I have come to the conclusion that the lack of crispness is essentially due to lack of inherent image detail - probably due to a combo of camera lens, camera shake, image movement and less than perfect focus.

Anyway, out of interest I have posted a crop showing (top) the untouched original and (bottom) a reworked version with levels adjustment, USM (70/1.4/0) on red and green channels and intrusive halos on the ant's body cloned out. I also used the history brush to remove USM from the background.

Bruce