Are Ants Cherry Farmers?

May 22, 2011 8:48 AM

What are these ants doing in my cherry tree? Difficulty: no aphids.

We have a young black cherry tree that's about 7 feet tall. It has ants all over it. Not swarms of tiny ants but a regular scattering of "standard" ants. They do not appear to be harming the tree. All the leaves are healthy.

They'll wander up to the little nubs (as in this picture), waggle their antennae about for a bit, and then wander away. They don't appear to be harvesting any sap or biting the nubs, but I could be missing it.

The vast majority of my general googling on the topic is people suggesting they're farming aphids. There is absolutely no sign of aphids.

If they're not hurting the tree I'm fine leaving them; I'm just extremely curious as to what they're doing.

Dumb secondary question: those little nubs are where cherries grow from, right? The tree is new to us and has not yet born fruit (are the ants somehow keeping it from bearing fruit?)

posted by carlh to home & garden (4 answers total)

No, the nubs are probably galls. Galls may ooze sap, which the ants collect. The ants are not harming the tree, but they do benefit if the tree is sick.

You will start seeing cherries when your tree starts to flower. If you've seen apple, pear, apricot, or peach trees flowering and bearing fruit, you know what cherry tree flowers look like.
posted by Nomyte at 9:58 AM on May 22, 2011

That makes sense about the flowers...yeah, I wasn't thinking.

In my research I had seem some references to galls and other infestations but for the life of me I can nearly guarantee that they are a natural part of the tree somehow. I have looked up lots of pictures of tree galls and they look random, ugly, and definitely parasitic. These nub-pairs are regularly spaced and at the base of every single leaf, and only at the base of every single leaf. The picture I posted shows two different leaves, but really every leaf on the tree is like that.

Also, to update my original post, I think we have a BlackGold Cherry tree, not a Black Cherry tree, if that matters.

I'm going to email my pictures to the nursery from which we bought the tree. They might know if it's a natural feature.

Hmm.
posted by carlh at 10:20 AM on May 22, 2011

Nomyte is nearly right. The nubs are nectar glands. The ants are attracted by the nectar, and will tend to drive off other more harmful insects. Ants in the absence of aphids are more of a help than a problem.

Galls, on the other hand, are created by wasps. Some galls produce a kind of nectar which encourages ants to tend the galls. But these are not galls.
posted by le morte de bea arthur at 10:35 AM on May 22, 2011

Brilliant! That sounds spot on. Very cool.
posted by carlh at 11:32 AM on May 22, 2011