bumblebees detect floral electric fields

[greengumbo]

DOI: 10.1126/science.1230883

Really cool paper on how bumblebees can detect different electric fields arounf flowers helping in foraging efficiency. Honeybees probably do similar I would think ?

ABSTRACT:

Insects use several senses to forage, detecting floral cues such as color, shape, pattern, and volatiles. We report a formerly unappreciated sensory modality in bumblebees (Bombus terrestris), detection of floral electric fields. These fields act as floral cues, which are affected by the visit of naturally charged bees. Like visual cues, floral electric fields exhibit variations in pattern and structure, which can be discriminated by bumblebees. We also show that such electric field information contributes to the complex array of floral cues that together improve a pollinator's memory of floral rewards. Because floral electric fields can change within seconds, this sensory modality may facilitate rapid and dynamic communication between flowers and their pollinators.

[Julian]

This floral deception is the bit I find really interesting.

The bees, in turn, change the charge of whatever flower they land upon. Robert’s team showed that the electrical potential in the stem of a petunia goes up by around 25 millivolts when a bee lands upon it. This change starts just before the bee lands, which shows that it’s nothing to do with the insect physically disturbing the flower. And it lasts for just under two minutes, which is longer than the bee typically spends on its visit.

This changing field can tell a bee whether a flower has been recently visited, and might be short of nectar. It’s like a sign that says “Closed for business. Be right back.” It’s also a much more dynamic signal than more familiar ones like colour, patterns or smells. All of these are fairly static. Flowers can change them, but it takes minutes or hours to do so. Electric fields, however, change instantaneously whenever a bees lands. They not only provide useful information, but they do it immediately.

These signals could either be honest or dishonest, depending on the flower. Those that carpet a field and require multiple visits from pollinators will evolve to be truthful, because they cannot afford to deceive their pollinators. Bees are good learners and if they repeatedly visit an empty flower, they will quickly avoid an entire patch. Worse still, they’ll communicate with their hive-mates, and the entire colony will seek fresh pastures. If the flower can signal that it is momentarily empty, then the bee will benefit and the flower will communicate honestly its mitigated attraction.

But some flowers, like tulips or poppies, only need one or two visits to pollinate themselves. These could afford to lie. It is expects that they will do everything possible to keep their electric charge constant, even if a bee lands upon them. They should always have their signs flipped to “Open”.

[Easy beesy]

So does this mean the 'footprint pheromone' is not utilised when foraging? Or is it as well as polarity?