Sunday, February 24, 2013
Last Thursday, British sensory biologist Dominic Clarke and other authors published research about detection of floral electric fields by bees in journal Science. The research involved studying bees’ reaction to flowers with different electric fields. The researches concluded that bees can choose flowers based on their electric fields, and remember them as they do with color and other characteristics of flowers.
This Friday Wikinews interviewed Dominic Clarke about the research.
((Wikinews)) What caused your initial interest in electric fields of flowers?
- Dominic Clarke: There has been a considerable amount of speculation in the scientific literature since the 60s about the role of electric fields in pollination. It has been suggested that the electric field that arises between a charged bee and a grounded flower may be responsible for increasing the efficiency of pollen transfer between the two. We looked at this literature as sensory biologists and naturally formed the question ‘can bees sense these fields?’. Since we couldn’t find any answers to that question in the literature, we decided to find out for ourselves.
((WN)) How was the new phenomenon discovered?
- DC: We use what’s called ‘differential conditioning’, where bees are trained to find a sucrose reward from an array of flowers, where only half of the flowers contain the reward. In our experiment, the flowers that were rewarded (with a sugary solution) were marked with a small electric field (about the same strength as around a flower in the wild). The ones that were not rewarded were not marked with fields. Since the electric field is the only thing that differs between the two flowers, we know that if the bees can learn to tell them apart, they can sense the electric field. Our bees were able to pick the rewarded flower 80% of the time when the electric field was present as a cue. When the electric field was switched off, they could only get it right half the time, which is the same as if they were just picking flowers at random.
((WN)) How many species of flowers and bees did you study during your research?
- DC: We focus on one species of bee, the bumblebee Bombus terrestris. And we look mainly at Petunia flowers (P. integrifolia). These two species provide the bulk of our data, but we do consider other flowers like geraniums, daisies, clematis and foxglove, and other species of bee (particularly the honeybee Apis mellifera).
((WN)) Do you have diagrams, sketches, or drawings of electric field around a bee and a flower?
- DC: I have attached a picture of a computer model of the electric field around a flower called “Flower Potentials and Fields”.
((WN)) Was it known that bees have a charge before?
- DC: Yes, reports as early as the 70s have measured electrical charge on bees, but it was not known before whether or not they could sense such charges.
((WN)) What environment did you study the flowers and bees in? A laboratory? A garden? Natural environment?
- DC: The behavioural tests were carried out in a laboratory because we needed to be able to precisely control the environment in which the bees were tested. Future work will be aimed at trying to get out into the bees’ natural environment and trying to figure out exactly what role(s) this sense plays in their lives.
((WN)) What equipment was used during the research? How did you measure the charge?
- DC: Charge was measured using a device called a “Faraday Pail”. It is basically an electrically shielded metal cup, the voltage of which changes according to how much charge is inside it. We can measure this voltage when a bee flies in and so measure its charge. We did this with 51 individual bees.
((WN)) What were the roles of the people involved in the research? What activity was most time-consuming?
- DC: It was very collaborative in all aspects of the research. I carried out the bulk of the experimental work and data analysis, but the process of designing the experiment, figuring out how to do the analysis, choosing which ideas to follow and which to put on the shelf etc., that is highly collaborative. Then of course comes the long period of writing, re-writing, re-re-writing, sending out to colleagues for feedback, re-re-re-writing, submission, peer-review, editing re-submission etc. which is also a collaboration between all the authors. A large part of doing science is talking as well; meeting, planning brainstorming. It feels to me like putting together the paper took the longest, but perhaps that’s just because it’s the most fresh in my mind.
((WN)) What do you see as possible directions for future research in this field? What do you think possible applications of the discovery can be?
- DC: The two big questions now are “how do the bees do this?” and “why do they do this?”. The first is a case of pinning down the sensory mechanism used by the bees to detect the fields, and the second will involve a great deal of field-based experiments. We need to get out of the laboratory and understand the role this phenomenon plays in the lives of bees in the wild.
((WN)) Thank you for sharing your insight and details. Have a good time.