Charged bees can sense electric flower fields
Positively charged bees are able to recognise electric signals given off by flowers as part of the plant pollination strategy.
The electrical signalling works in tandem with other signs such as colour, pattern and fragrance to tell bumblebees (and other insect pollinators) about the amount of nectar and pollen they may contain.
“This novel communication channel reveals how flowers can potentially inform their pollinators about the honest status of their precious nectar and pollen reserves” said co-author Heather Whitney of the University of Bristol.
Generally the flowers are negatively charged and generate a weak electric field while the bees become positively charged as they fly around — the study suggests the charge can build to around 200 volts. The sensation felt by a positive bee meeting a negative plant can be enough to convey snippets of information while its absence could reveal whether the flower has recently hosted another insect.
The biologists noted that not only could the bumblebees tell the difference between various floral electric fields, but when learning to tell two colours apart having an electric field involved sped up the process.
“The co-evolution between flowers and bees has a long and beneficial history, so perhaps it’s not entirely surprising that we are still discovering today how remarkably sophisticated their communication is,” said Daniel Robert, who also worked on the study. He also stressed how a bee’s intelligence made it necessary for the flowers to develop an effective communication strategy: “bees are good learners and would soon lose interest in such unrewarding flowers”.
The exact mechanics by which the bees detect these electrical variations is not fully understood, although the explanation favoured by the researchers is that coming near the charged flowers causes the bees’ fur to “bristle”, like when you hold the back of your hand a couple of millimetres from an old TV screen.
Image: Laurent Jégou / CC BY ND 2.0