

Apr 04, 2014

Bees can sense the electric fields generated by flowers

Previous Picture of the Day articles discuss aspects of biology that rely on electricity. Whether it is the transportation of nutrients and electrolytic compound in and out of cells, or the motive action of bacterial flagella, electric charge exchange is a necessary component for life to exist.

Last year, scientists from the University of Bristol’s School of Biological Sciences announced an important discovery: bees, specifically bumble bees, carry a positive electric charge that they use to sense negative electric fields surrounding flowers. According to Professor Daniel Robert: “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.”

Since plants are anchored in the ground, they acquire negative charge—they are “grounded”. Bumble bees, on the other hand, beat their wings about 200 times per second, on average, causing a positive charge to build-up on their bodies. This happens because friction with air molecules reduces their negative charge, in the same way that walking across a nylon carpet reduces the negative charge on a human body, resulting in a spark when a grounded metal object is touched. Sparks are not generated between bees and flowers, but the researchers think that fine hairs on a bumble bee’s body “stand up” when it approaches the electric field of a flower.

Somehow, the electrostatic force between bee and flower improves a bee’s memory. It is better able to distinguish over time those flowers that will provide it with the greatest payoff. When the electric fields are reduced in flowers, bumble bees are not as good at determining which flowers to visit.

Bumble bees use many senses to detect flowers that are ripe with pollen and nectar. They are sensitive to ultraviolet light, which is emitted most strongly when a flower is ready for pollination. They can also sense a flower’s fragrance. However, those signals are the primary attractors. What tells a bee that a particular flower will continue to provide nectar? How does it know if other bees have depleted the supply?

Robert and his colleagues discovered that when a bumble bee lands on a flower, there is a mutual charge exchange. A flower’s electric field is reduced by a small amount with each contact. The weaker the electric field, the more bees have landed, so an individual bee might be sensing the difference in potential, thereby knowing how many bees have visited a particular flower. A reduced electric field means that the reward will not be as great, so it does not waste energy trying to feed on flowers with less nectar.

Since flowers are not good electrical conductors, charges accumulate slowly in their structures, possibly in accordance with the replenishment of their nectar supplies. Therefore, a bee “sees” the recharge process, and understands when it is time to revisit a flower.

Perhaps electric charge exchange is going on between plants and other animals, as well—even human beings. It is becoming more obvious to nutritionists that a largely plant-based diet is far healthier for human consumption than meat, dairy and grains. It could be that eating the negatively charged plants helps to reduce the overall positive charge that human beings accumulate because of exposure to air pollution, or positive electric fields from computers and other electronic equipment.

One of the presentations at the Electric Universe conference in 2013 was by Dr. James Oschman. In it, he advised that human beings ought to be more connected to the ground because Earth is connected to the ionosphere. Lightning strikes distribute negative charge into the ground, and walking barefoot helps reduce the positive charge in the body. Eating negatively charged green plants might also be beneficial in the same way. Wheat gluten, on the other hand, is positively charged, so may not be as advantageous to human nutrition.

The Electric Universe is omnipresent. From deep space to atomic interactions, everything is electrical in nature. Galaxies transact with their neighbors along Birkeland current filaments that could be billions of light-years long. The cells in our bodies carry electric charges more powerful than a lightning stroke. It is not surprising that new discoveries reveal new ways that electricity governs the world.

Stephen Smith