Perhaps my favorite thing about the fascinating recent report [1] that bees sense the electric field of flowers, and learn from these electrical cues what flowers to visit, is that reminds me that it’s still possible to do simple, elegant experiments. To test bees’ field recognition, the authors built “E-flowers” consisting of metal and epoxy disks held at different voltages, with different “rewards” of pleasant sucrose solutions and bitter quinine. They then simply monitored the visits of bumblebees, collecting fascinating data on sensing, learning, and even information transfer (as the visits of bees alter the electrical charge of the visited flowers). It’s the sort of experiment that we all could have done a hundred years ago, had we been clever enough to think of it!
It is, of course, also wonderful that bees can sense electric fields. Electroreception in general is remarkable. It’s especially mind-boggling, I think, in many aquatic animals, since electric fields in water decay within nanometers. I was reminded of this again when reading about platypuses with my 3-year old a few days ago; platypuses rely heavily on detecting their preys’ electric field, since their other senses are fairly awful. (For the technically-minded: Consider a shrimp with a surface potential of 100 mV, in water with an exponential screening length of 10 nm. What’s the field strength at the bill of a platypus, 1 cm away?) If a kind reader supplies the platypuses, I’ll build the E-shrimp!
The kids and I painted owls this morning; I did a quick bumblebee, too:
[1] D. Clarke, H. Whitney, G. Sutton, D. Robert, Detection and Learning of Floral Electric Fields by Bumblebees, Science 340, 66–69 (2013) http://www.sciencemag.org/content/340/6128/66 ; Here’s an NPR article: http://www.npr.org/2013/02/22/172611866/honey-its-electric-bees-sense-charge-on-flowers
The Eighteenth Elephant 