by Emma Murphy, Master Gardener

Ants are everywhere, but only occasionally noticed. They run much of the terrestrial world as the premier soil turners, channelers of energy, dominatrices of the insect fauna ~ Bert Holldobler

This spring I noticed that my patches of native bloodroot (Sanguinaria canadensis) and large-flowered bellwort (Uvularia grandiflora) appear to have spread to places where I didn’t plant it. So that got me wondering “how did that happen?”

Apparently the answer is myrmecochory, which is defined as the dispersal of seeds by ants. Many plants have evolved to depend on a specific group of insects to disperse their seeds—in this case ants!

Plants that use ants to disperse their seeds have a fat-filled structure on the seed exterior called an elaiosome, which is a super snack for an ant. These structures or “food bodies” are rich in lipids, amino acids or other nutrients.

Elaiosome (e-lay-o-zome)
(Greek: elaion=oil + soma=body) literally meaning ‘oil body’

Plants that use this technique include many of the spring ephemerals such as trout lily (Erythronium americanum), violets (Viola spp), trilliums (Trillium spp), bloodroot, wild ginger (Asarum canadense), dicentra (Dutchman’s breeches, squirrel corn, bleeding hearts), hepatica, spring beauty (Claytonia virginica), large-flowered bellwort, and sedges in the Carex genus.

How it Works

• Elaiosome Production
  Myrmecochorous plants produce seeds with an elaiosome
• Ant Attraction
  The elaiosome attracts ants, who are drawn to the food source.
• Seed Transport
  Ants carry the seed back to their nest, where they consume the elaiosome.
  • Seed Dispersal
    The seed is then discarded, often near the ant nest, providing a good environment for germination and seedling establishment.

The seeds are dispersed away from the parent plant, which reduces competition with the parent plant and improves chances of successful germination in the new spot. The ants may also discard the seeds in nutrient-rich areas within the colony, further enhancing germination success.

Thanks to the ants, the seeds are buried in nourishing soil, protected from predators (e.g., slugs and mice) who would eat the entire seed, not just the elaiosome.

Myrmecochory occurs worldwide, with over 11,000 plant species depending on this partnership. In eastern North America, ants in the genus Aphaenogaster do the majority of the work. These ants nest in leaf litter and woody debris on the ground, so it’s important to minimize plowing and soil disturbance.  

Ants are Important

Ants are a vital part of our ecosystem and worth protecting. They are keystone species – their diversity and behaviour affect their habitats and the surrounding plant and animal communities. So by conserving ants, we protect many other organisms that rely on them for the lifecycles.

The intricate tunnels and galleries ants create loosen the soil and allow moisture, nutrients, and air to move downwards. They carry leaf litter, prey, and other food items deep into the soil, which then are broken down by other invertebrates and microbes into the nutrients that all plants need to grow.

So next time you see your favourite spring plant has popped up in another location, thank the ants!

Want More Information?

Don’t crush that ant—it could plant a wildflower

Ants As Seed Dispersers a.k.a. The Myrmecochory Episode!

Ants Aren’t Your Enemy