Photo by Annemarie Mountz, from http://phys.org/news/2013-02-bees-electrical-fields.html

Flowers seduce bees with attractants such as color, shape, and scent. Scientists now think that flowers may have another surprising attractant in their repertoire: electric fields.

Researchers in the UK found evidence suggesting that different flowers produce distinct patterns of electric fields. They hypothesized that bees can sense these patterns and learn to associate them with rewards like nectar, thereby reinforcing further visits to the flowers and promoting pollination.

To test their idea, researchers built fake flowers. Half of the fake flowers contained a sugar reward, and half contained a bitter, aversive substance. Bumblebees visited tasty flowers and aversive flowers with equal frequency. However, when the tasty flowers were given a biologically relevant charge of 30V, after 40 visits bees had learned to associate the electric field with the reward—they visited the tasty fake flowers ~80% of the time. Bees could also learn to distinguish between fake flowers with differently shaped electric fields.

But why should flowers bother with yet another attractive cue? Researchers think that flowers are using multiple cues together to enhance their relationships with bees. They showed that bees could learn which flowers to visit much more rapidly when they were presented with two cues (color and electrical charge) compared to a single cue (color only). The communication between bees and flowers is evidently more complex than we thought.

For more information, check out these articles:

http://www.sciencemag.org/content/340/6128/66
http://phenomena.nationalgeographic.com/2013/02/21/bees-can-sense-the-electric-fields-of-flowers/
http://phys.org/news/2013-02-bees-electrical-fields.html

To read about the global decline of bee populations, see this new SITN Signal to Noise article: http://sitn.hms.harvard.edu/flash/2014/buzzkill-where-have-all-the-bees-gone/