https://www.scientificamerican.com/article/bumblebees-bite-plants-to-force-them-to-flower-seriously/

Bumblebees are a resourceful bunch: when pollen is scarce and plants near the nest are not yet flowering, workers have developed a way to force them to bloom. Research published on Thursday in Science shows that the insects puncture the plants’ leaves, which causes them to flower, on average, 30 days earlier than they otherwise would. How the technique evolved and why the plants respond to bumblebee bites by blooming remain unclear. But researchers say the discovery of a new behavior in such a familiar creature is remarkable.

“This is one of those really rare studies that observes a natural phenomenon that hadn’t been documented before,” says John Mola, an ecologist at the U.S. Geological Survey’s Fort Collins Science Center in Colorado, who was not involved in the study. The new finding “offers all sorts of questions and potential explanations” about how widespread the behavior is and why it occurs, he says.