Thursday, August 1, 2013


Yup, it was kinda like that.

I was clearing out an overgrown area of our garden when I reached in to cut a tall weed, a goldenrod. Instantly, my arms began to sting and I thought I'd rubbed against stinging nettles. When I looked down, I was horrified to see dozens of ants swarming over my bare arms, biting away to beat the band.

After I finished a vigorous arm-waving dance, I thought, what kind of fresh gardening hell is this? My next thought was, KILL THEM ALL! (This from a woman who never uses pesticides or herbicides and displays a certified wildlife habitat sign in her yard.)

I used a garden tool to drag the still-swarming plant onto a sheet of newspaper to get a better look.

These speedy, medium-sized ants looked ordinary enough. Why were they suddenly attacking me? In forty years of gardening, I have never before encountered aggressive ants like these and I did not like this new development one bit.

Looking closely, I could see that the ants seemed to be either eating or tending to some kind of larvae on the plant.
Off to the Internet I went. It took a bit of digging, but I think I have solved the mystery. It turns out, this was more about the goldenrod than about the ants.

According to Don and Lillian Stokes* goldenrod produces a great deal of nectar and pollen, which in turn attract myriads of insects.
Two kinds of insects feed on the leaves of goldenrod.

The Stokes write,  "These are treehoppers (Pubilia, Membracidae), which poke into the leaves and feed on the sap, and goldenrod beetles (Trirhabda, Chrysomelidae), which eat the leaves as larvae and adults.  An interesting relationship exists between these two insects and certain ants.  In one study it was shown that a species of treehopper, Pubilia concave, lays its eggs on goldenrod plants that are near the mounded homes of Formica ants.  The young treehoppers exude excess sap as they feed, and the ants crawl up the goldenrod and feed on this sap.  The ants and treehoppers thus form a mutual relationship that benefits both:  the treehoppers give the ants their excess sap, while the ants protect the treehoppers from predators."

 The Stokes go on to say that when the ants and treehoppers are on a plant, the ants are aggressive.
So there I had it. The ants were protecting their goldenrod feeding buddies. Aggressively.

I read further in other sources that this variety of ant (pronounced FORM' ic a) is actually good for a garden, feeding on lots of garden pests. They also never come into the house. So maybe I won't be killing them all after all and I can keep my wildlife habitat creds.

But I tell you one thing, I'm not letting the goldenrod get away from me again. And if I do, I won't be blithely clipping it back with garden shears. It can just sit there until the depths of January.

 * From A Guide to Enjoying Wildflowers, by Donald and Lillian Stokes.   Stokes Nature Guide Series.  Little, Brown & Company.