How do bees know which flowers to visit, and where on the flowers to land?
Visual cues are part of the answer. It has already been known that bees and other insects see flowers differently than humans do. Bees can sense both visible and ultraviolet light, and many flowers have markings in both wavelength (color) bands, which help to both attract pollinating insects from a distance, then guide them in to the center areas where they can find the nectar (and at the same time pollinate the flower). Bees can also detect plumes of fragrance from flowers.
It was also previously known that flowers have a slight negative electrical charge, whereas bees pick up a slight positive charge by colliding with dust particles while flying through the air. It had previously been observed with high-speed video that just before a bee lands on a flower, the positively-charged pollen particles on the bees’ legs jump across the gap and stick to the negatively charged flower.
New research published in Science Magazine shows that flowers have specific electric field patterns pointing the way to their center where the nectar is located. As we recently highlighted from a related paper in PNAS (6/08/16), the tiny hairs on the legs of bees can sense electrical charges, such as these electrical patterns on flowers.
To test bees’ responses to the flowers’ patterns, researcher Dominic Clarke and his team created artificial flowers with a ‘bulls-eye’ electric field pattern and filled them with sugary nectar, while filling identically-colored artificial flowers with a generic electric charge with a bitter liquid. In their experiment, bees quickly learned to go exclusively to the patterned flowers (70% accuracy). When the electric fields were turned off, the bees could no longer tell the flowers apart.
To view the flowers’ electric fields, the researchers sprayed brightly-colored positively-charged particles on the flowers, then took photographs. (Beautiful photographs are viewable at National Geographic’s article.
Not only do the flowers provide these ‘electric signs’ for the bees, their voltage also changes in time to provide further guidance for the bees. Immediately after the bee lands on a flower, its negative charge decreases by 25 millivolts, and it stays reduced for about two minutes. This difference in electric field for recently-visited flowers may help bees sense which flowers have not been visited in a while, thus hold more nectar.
How could this intricate mutually-beneficial system evolve? Which came first, the bees’ system of leg hairs, neural connections, and neural processing to sense and understand the electric fields, or the flowers’ system of more– and less-conductive anatomical patterning that points the way to their nectar, and the flowers’ finely-tuned passive or active system for adjusting its voltage signal in real time?
Evolutionists like to claim that in such “irreducibly complex” systems, each part must have had some other function at some time. Fine — let them show this. As Darwin wrote, “If it could be demonstrated that any complex organ existed, which could not possibly have been formed by numerous, successive, slight modifications, my theory would absolutely break down.”
In order for this symbiotic electric field ‘dance’ to be beneficial to either species, all the parts had to work together. A genetic mutation that changed flowers’ electric fields would be useless if pollinators could not sense them, and would be selected against because of the wasted energy involved. Likewise, a mutation that gave bees hairy legs would be useless and wasteful without the neural processing circuits to understand the hair signals. Neurons growing down into bees’ legs and neural sensory-integration centers without sensor hairs would also be useless.
Instead, it makes more sense to view these interacting species as having been designed for each other by God. Two unique species ‘serving’ each other and helping each other in mutually-beneficial ways is precisely the type of beautiful interaction we would expect, based on the character of the God of the Bible.
[Guest article by an engineering professor]