The bumblebee is a critical part of the pollination process that helps plants and flowers grow. Scientists at ETH have demonstrated an interesting way that bumblebees damage plant leaves to accelerate flower production when pollen is in short supply. The researchers found that bumblebee workers use their mouths to pierce the leaves of plants that haven’t flowered yet and that the resulting damage stimulates the production of new flowers that bloom earlier than those in plants the bees haven’t damaged the leaves of.
The researchers say that past work has shown that various kinds of stress can induce plants to flower. Still, the role of bumblebee-inflicted damage on accelerating flower production was unexpected. Researchers say that other scientists had observed such behavior, but no one had explored what the bees were doing.
Based on lab studies, scientists were able to show that the bumblebee inflicted damage to the plants had a strong correlation with the amount of pollen they could obtain. The bees were damaging leaves more frequently when there was little or no pollen available. Scientists also discovered that the damaged the bees inflicted had a significant impact on the flowering time in two different plant species.
When the bees damaged the leaves of tomato plants, they flowered up to 30 days earlier than those that hadn’t been targeted. Mustard plants flowered about 14 days earlier after bees damaged their leaves. Research suggests that the developmental stage of the plant when it is bitten by bumblebees can also influence the degree to which flowering is accelerated. Researchers plan to explore that aspect in the future.
Bees were observed in more natural conditions when a rooftop garden filled with wildflowers was mowed. In the experiment, the researchers found that hungry bumblebees with insufficient pollen supplies frequently damage the leaves of non-blooming plants. When more flowers were available to the bees, the damaging behavior was reduced.