The Light Eaters: How the Unseen World of Plant Intelligence Offers a New Understanding of Life on Earth

Certain insects are described as “eusocial,” meaning they participate in a form of collective behavior that emphasizes the benefit of the whole over the survival of the individual. Ants, bees, and humans all exhibit eusocial behavior. In Chapter 9, Schlanger asks whether plants also can engage in eusocial behavior. Some research suggests they do.

Evolutionary ecologist Susan Dudley discovered that searocket plants behave differently around their own kin than they do other plants. When planted close to unrelated plants, searockets take an aggressive approach, pushing out the roots of other plants, taking up space. When planted close to their relatives, however, searocket plants are more amenable, leaving enough space to share nutrients with their kin. Dudley shared with Schlanger that the only reason she made this discovery was because she consciously set aside the scientific assumption that plant behavior is driven by evolutionary benefit. Instead, she asked if something else might be happening.

There are numerous examples of plants changing their behavior to prioritize the well-being of plants with close genetic markers. Sunflower farmers in Argentina discovered that planting relatives close together could increase yields, as these plants shared space more effectively than when partnered with unrelated rivals.