Lifestyle

When you see a wildflower, thank an ant

Posted May 28, 2020 6:00 am

Valerie Blaine

This ant is feasting on the food packets (elaiosomes) of Dutchman's Breeches seeds. When she's finished her meal, she will discard the seed nearby - and with luck, that seed will become a wildflower next spring. Courtesy of Valerie Blaine

Ants have never made it to the “most loved insect” list. I venture to guess that the average Joe hates ants. While ants inside our homes means trouble, the presence of native ants in the woods and prairie is a good thing.

One big job that ants perform this time of year is seed dispersal. Several species of wildflowers in our area rely on ants to take their seeds and spread them about the woods. (In case you need a new Scrabble word, the term for this is myrmecochory.) Worldwide, this strategy is found in 80 plant families.

To attract ants, plants like Dutchman's Breeches offer a tasty treat. The food packet, called an elaiosome, is irresistible to hungry ants in the spring. Courtesy of Valerie Blaine

Plants entice ants to do the heavy lifting by offering a reward. Attached to each seed is a tasty, power-packed treat called an elaiosome. Filled with lipids and proteins, the elaiosome draws hungry worker ants, who carry the seed to their nest. This often occurs early in the year when other food sources for ants are scarce. Calorie-loaded elaiosomes provide the energy needed to build new colonies in spring.

Food packets (elaiosomes) are attached to Bloodroot seeds to attract ants. Here, an ant begins to sample the menu. Courtesy of Valerie Blaine

After the ants have consumed the nutritious elaiosomes in the nest, they discard the seeds in their trash pile, outside the nest.

Voilà! The seeds have not only been spread; they've been planted. The soil near ant nests is often very fertile - so the seeds have a great start in life.

To prevent the seed itself from being eaten, many plants produce seeds with very tough coats. Ants can easily eat the elaiosome that's attached to the seed, but the seed is coated in protective armor.

This is similar to fleshy fruits like cherries and apples. Animals eat the sweet stuff on the outside, and eject the seed, or pit.

The delicate flowers of Hepatica are favorites in early spring. This is another species that relies on ants to disperse the seeds. Courtesy of Valerie Blaine

An estimated 30% of spring wildflowers in eastern North America are dispersed by ants. Some of our most beautiful spring wildflowers are among this group. There's Hepatica, Dutchman's Britches, Bloodroot, and Wild Ginger, to name a few.

Bear in mind that there are native ants, and there are nonnative (exotic) ants. The latter include nuisance species that annoy us indoors. These pests are the ones that give all ants a bad name. However, according to biologists James Trager and Laura Rericha, there are “relatively few” exotic ants in Illinois, particularly among outdoor ants.

Dutchman's Breeches bloom in April in northeastern Illinois. These wildflowers often carpet the woodlands in breathtaking displays. Courtesy of Valerie Blaine

The native ants are the good guys. Trager and Rericha wrote that 129 species of these have been documented in Illinois. Many of these native ants are dispersing seeds of our most beautiful wildflowers, right now.

Ants in your plants can be a good thing. When the first spring wildflowers appear next year, thank an ant!

Valerie Blaine is a naturalist in St. Charles. You may reach her at natvblaine@gmail.com.

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