Saw this report just now in Popular Science. Enjoy!
Various flowers (Left: Geranium magnificum; Middle: Gerbera hybrida; Right: Clematis armandii) showing a composite of immediately before and after application of charged powder paint. The pattern of powder deposition reveals the shape of the electric field. Image by Dominic Clarke and Daniel Robert
"Bumblebees distinguish flowers based on their colors, patterns, scents, and - as scientists recently discovered -electric fields. Researchers from the University of Bristol created charged and neutral artificial flowers, and based on thousands of flight landings, found that bees could tell differently charged charged flowers apart. While bees are usually positively charged, flowers are negatively charged; the difference in electric potential helps pollen stick to bees. And because a flower's electric field changes shape after an insect lands on it, bees may use that information to preferentially visit flowers where bugs haven't yet nabbed the nectar."