Gardening For Ants? Yes, You Can!

This is an idea that is probably well ahead of its time, but after writing about how you can plant a garden to encourage bees last week, I decided to figure out if you can plant a garden to encourage ants. I think the answer is, “Yes!” and if you are interested in ants, you’ve probably already been doing some of these things.

What do you need to provide to encourage ants in the garden? The same things you would provide for butterflies or bees:  food, water and shelter.

1. Plants with extrafloral nectaries provide food and water for ants

Bees collect pollen and nectar from flowers, which is why they are great pollinators. Ants also have relationships with plants, but it often much more subtle. Many plants have nectaries, which are glands that produce sweet fluid fluids, outside of those that reside in the flowers. These nectaries, called extrafloral nectaries or EFN’s, are often used almost exclusively by ants. They supply both water and nutrients.

You are probably already familiar with one well-known example of extrafloral nectaries in the popular landscape plant, the peony. Ever see ants crawling all over peony buds right before the blossom opens?

Peonies have very small extrafloral nectaries along the outside edges of the flat, leaf-like scales of the flower buds. The nectaries provide a mixture of sugars, water and amino acids that attracts hordes of ants. In exchange the ants chase off or eat herbivores that might attack the bud. They also protect the peony “fruit.”

Sunflowers are another example. They have big showy flowers that attract bees.

If you look on the stems, however, you are likely to find ants. The ants are visiting extrafloral nectaries for food. (see another post about ants on sunflowers)

Over 70 different families, from buttercups to violets have extrafloral nectaries. The nectaries may be dripping nectar during definite seasons of the plants’ life cycle, for example for a week or so while the plant is blossoming, or may be available year round.

Here in the Southwest, many cacti have extrafloral nectaries.

It is thought that ants provide various services in exchange for the free meal. (For more information, try these posts about other plants with nectaries:   red bird of paradise, vetch, spurges)

2. Providing food- aphids or scale insects

Now you’ll think I’ve gone over the deep end, but if you are serious about gardening for ants you might want to provide some plants that are hosts to aphids or scale insects.

Leaving a few weeds that are prone to aphids doesn’t necessarily mean your garden will be infested, because some aphids are specific to only one or a few plants. An example is the thistle aphid, Brachycaudus cardui.

Ants definitely benefit from the honeydew the aphids secrete, as do a number of other insects and even birds. You may also benefit, because it is easy to spend hours studying the complex relationships involved.

3. Providing shelter for ants

Can you provide shelter for ants? It might be more simple than you realize. You just need to have a few of these:

Well, maybe not so artistically arranged.

A few flat rocks strewn about your garden are likely to provide a valuable resource for ants. In the cooler parts of the year, ants use rocks that are warmed by the sun as incubators for the larvae. In fact, these particular rocks have a colony of rover ants under them doing just that this week.

4. Get to know your local ants

One of the best ways to develop an ant-friendly garden is to find out what species are found in your area and what their requirements are. Find out which species are keystone species important to your local ecology and which are introduced pests that should be discouraged. You are likely to be a pioneer, so keep records and share what you find out.

Looking back, it seems like gardening for ants could be a real possibility. In fact, if you know of a publisher who might be interested, I would be willing to write up a guide. I can guarantee it would be one of a kind 🙂

Now, you may ask, “Why on earth would you want to encourage ants?”  More about that next…

Nectaries on Red Bird of Paradise

The red bird of paradise, Caesalpinia pulcherrima, is a plant with large, attractive red-orange-yellow flowers. It is a popular plant in desert landscapes.

The flowers have long stamens, and is thought to be pollinated by butterflies, especially swallowtails that flutter their wings while feeding.

This flower also has an ant.

Can you see it now?

It’s a rover ant, Brachymyrmex patagonicus. Any ideas what the ant might be doing?

The swollen gaster might be a clue.

Honey bees and wasps exhibit the same behavior.

Here’s another clue.

Apparently these plants have extrafloral nectaries as well as nectaries within the flowers. Isn’t it funny where all these extrafloral nectaries show up on desert-adapted plants?

R. W. Cruden and Sharon M. Hermann-Parker. 1979. Butterfly Pollination of Caesalpinia Pulcherrima, with Observations on a Psychophilous Syndrome. Journal of Ecology. 67( 1): 155-168

Ants of Tucson, Arizona: Crematogaster opuntiae

There is a story on the Internet of a myrmecologist (unfortunately unnamed) finding 10 species of ants, including army ants, while waiting for a flight at the Tucson, Arizona airport. I had two hours in Tucson on Saturday morning, so I wondered if I could do as well. For the next few days we’ll see if I was up for the challenge.

The first ant I found was a worker of the genus Crematogaster, named for its lovely heart-shaped rear section or gaster. This cutie is Crematogaster opuntiae, a specialist often found feeding on the extrafloral nectaries of cacti. This particular cactus is a cholla, Cylindropuntia.

Although Crematogaster opuntiae workers are known for chasing herbivores away from cacti in defense of the extrafloral nectaries, they are also predators of other insects, such as termites.

For more information, try:

Charles H. Pickett and W. Dennis Clark. (1979).The Function of Extrafloral Nectaries in Opuntia acanthocarpa (Cactaceae) American Journal of Botany. 66(6):618-625.

Discover Life has a photograph of Crematogaster opuntiae raiding termites

Alex Wild also has some fabulous photographs

Finally, if your French is good, Fourmis et Cactus à Nectars Extra-Floraux