In the summertime, the air is thick with the low humming of bees delivering pollen from one flower to the next. If you listen closely, a louder buzz may catch your ear.
This sound is the key to a secret stash of pollen that some flowers hide deep within their anthers, the male parts of the plant. Only pollinators that buzz in just the right way can vibrate tiny grains out of minuscule holes at the top of the anthers for a protein-rich snack.
The strategy, called buzz-pollination, is risky. But it’s also critical to human agriculture. Tomatoes, potatoes and eggplants need wild populations of buzz pollinators, such as bumblebees, to produce fruit. Honeybees can’t do it.