Bumblebees aren’t merely bumbling around our gardens. They’re actively assessing the plants, determining which flowers have the most nectar and pollen, and leaving behind scent marks that tell them which blooms they’ve already visited.
Now, a new study reveals that bumblebees force plants to flower by making tiny incisions in their leaves—a discovery that has stunned bee scientists.
“Wow! was my first reaction,” says Neal Williams, a bee biologist at the University of California, Davis. “Then I wondered, how did we miss this? How could no one have seen it before?”
Consuelo De Moraes, a chemical ecologist at the Swiss Federal Institute of Technology in Zurich, had the same reaction when one of her students, Foteini Pashalidou, noticed buff-tailed bumblebees making tiny incisions in the leaves of their greenhouse plants. The insects didn’t seem to be carrying off the bits of leaves to their nests or ingesting them.
Suspecting the bees were inducing the plants to flower, the team set up a series of experiments. The results show that when pollen sources are scarce, such as in a greenhouse or...