5. Ant Seed Dispersal

Trillium seeds with attached elaiosome

Many people think of plants as stationary organisms. Individual trees definitely don’t walk from one place to another, but plant populations have evolved numerous mechanisms for getting their seeds from one place to another. Seeds can float on water, drift through the air, be digested and deposited by birds, or be buried and forgotten by squirrels. Some plants, like Jewelweed (Impatiens capensis) produce spring-loaded pods that launch seeds when touched. Others employ a strategy known as myrmecochory, a fancy term for ant-driven seed dispersal. 30-40% of understory plants in Northeastern forests are myrmecochorous.

Ant-dispersed plants produce elaiosomes— fleshy, nutrient-packed organs attached to their seeds. Ants are magnetically attracted to these lipid-dense morsels which they carry back to their colony. The seed is discarded or forgotten near the nest, giving it a chance to germinate and renew the cycle in a different location. The significance of elaiosomes ripples up the food chain: Aphaenogaster, an ant genus known for its seed dispersal, is a favored meal of the Eastern Red-backed Salamander (Plethodon cinereus). 

Some of the many ant-dispersed plants at Garden in the Woods include Trillium spp., Bloodroot (Sanguinaria canadensis), Trout Lily (Erythronium spp.), Wood Poppy (Stylophorum diphyllum), Wild Ginger (Asarum canadense), and Violets (Viola spp.).