Friday, June 17, 2011

What is attracting these ants? The Answer

In my last posts I asked if you can guess what is attracting these ants?
 I also showed a close-up of what the ants were after.
   I did have an unfair advantage because I could investigate where the little droplets were coming from.  All I had to do was look up and look for an ant farm.

Ants farming aphids
    Right above the leaves in question, the ants were farming aphids on the underside of a leaf.  Ants farm aphids by herding them, protecting them, and milking them.

Ant tending aphids
   Ants farm aphids so they can "milk" the honeydew the aphids excrete.  This sweet substance is a waste product of the aphids.  Since the aphids feed on plant sap they need to process a lot of sap to get enough essential amino acids. All that sap gives them too much sugar so they excrete the excess, the sugary liquid waste called honeydew.      In the photo below there is a group of aphids on the right side of the photo and concentrated on a leaf vein.  A small aphid is tipped up and is excreting a glistening drop of honeydew from its rear end.  Below the small aphid and to the left a bit is a larger aphid doing the same thing.

Now back to the question, "what is attracting these ants?" the answer is, "aphid honeydew".

   The ants weren't milking the aphids fast enough and so they just "let 'er fly".  The honeydew droplets landed on leaves lower down on the bush where other ants were imbibing the sweet honeydew drops.
   My backyard is a bonanza of astounding natural phenomenon.

Here is a link to an article on how ants herd aphids.


  1. Dana, the image of the aphid excreting the honeydew is amazing. Followed the link to learn more. Thanks for not keeping me hanging for long on the answer to your question.

  2. Sybil,
    Someday maybe I'll be able to photograph an ant actually "milking" an aphid. If I do, I'd like to use my Nikon with some kind of macro lens.

  3. Anonymous7/26/2015

    Very nice and interesting discovery.