For people, and many other animals, family matters. Consider how many jobs go to relatives. Or how an ant will ruthlessly attack intruder ants but rescue injured, closely related nestmates. There are good evolutionary reasons to aid relatives, after all. Now, it seems, family feelings may stir in plants as well.
A Canadian biologist planted the seed of the idea more than a decade ago, but many plant biologists regarded it as heretical—plants lack the nervous systems that enable animals to recognize kin, so how can they know their relatives? But with a series of recent findings, the notion that plants really do care for their most genetically close peers—in a quiet, plant-y way—is taking root. Some species constrain how far their roots spread, others change how many flowers they produce, and a few tilt or shift their leaves to minimize shading of neighboring plants, favoring related individuals.
“We need to recognize that plants not only sense whether it’s light or dark or if they’ve been touched, but also whom they are interacting with,” says Susan Dudley, a plant evolutionary ecologist at McMaster University in Hamilton, Canada, whose early plant kin recognition studies sparked the interest of many scientists.
Beyond broadening views of plant behavior, the new work may have a practical side. In September 2018, a team in China reported that rice planted with kin grows better, a finding that suggested family ties can be exploited to improve crop yields. “It seems anytime anyone looks for it, they find a kin effect,” says André Kessler, a chemical ecologist at Cornell University.