February 22, 2013
Electric Flowers Help Transfer Pollen To Pollinator
Brett Smith for redOrbit.com - Your Universe Online
Previous research has shown that bees build up an electrical charge as they buzz through the air, but a new study from the University of Bristol in the U.K. has shown that the bees are able to use this charge to interact with nectar-bearing flowers.
According to a summary of the study recently published in the journal Science, the British scientists showed that flowers actually modify their own electrical fields to attract the flying pollinators. The discovery adds electrical signals to the scents and color patterns that flowers have been known to use to attract bees.
"Of course it has existed for a long time, but this is a new way we can look at the interactions between bees and flowers," study co-author Daniel Robert, a biologist at of the University of Bristol, told BBC. "This doesn't throw away any of the previous work on cues that flowers are using, it adds another layer on top of that."
The Bristol researchers said they were initially trying to understand the exact mechanism behind how pollen is transferred from a flower to a pollinator. "What the pollen needs to 'know' is when to 'jump' onto the 'vehicle' — the bee — and when to get off it. So it's a selective adhesion type of question," Robert said.
To understand how electrical signals allow bees and flowering plants to interact, the research team placed electrodes in the stems of petunias and then monitored the plants as bees approached, landed on the flowers, and flew away.
They found that as the bees approached the flowers, the negatively-charged plants increased the voltage that they were emitting. Once the bees landed and began to extract nectar, the plant voltage reached its highest level. After the bees took off, the plant´s voltage emission remained at an elevated level.
Based on this observation, study co-author Dominic Clarke designed "fake" electric flowers to be used in a laboratory setting. These flowers gave off a positive charge and offered a sucrose reward to bees, while other uncharged flowers offered a bitter quinine solution. After 50 visits into the fake flower setting, the bees had learned to tell the difference between the flowers by the last 10 times.
Clarke noted that when he turned off the electric field, "the bee goes back to selecting at random because it hasn't got a way to tell the difference between them anymore.”
"That's how we know it was the electric field that they were learning,” he said. "Animals are just constantly surprising us as to how good their senses are. More and more we're starting to see that nature's senses are almost as good as they could possibly be."
Another recent UK study from the University of Cambridge showed that bees are more attracted to contrasting colors while searching for nectar. Based on observations, the study found how different patterns of pigmentation on flower petals can influence bumblebees' behavior. The researchers noted how a flowers color veins give pollinators clues to the location of the flower´s nectar.