Engeland: Bloemen en bijen communiceren via elektrische velden

vrijdag, 22 februari 2013 - Categorie: Onderzoeken

Bron: Press release University of Bristol, 21 febr. 2013

Een interessant persbericht over experimenten gedaan op University of Bristol. Volgens de onderzoekers zijn planten meestal negatief geladen en zenden ze zwakke elektrische velden uit. Bijen zouden iets positief geladen worden als ze door de lucht vliegen. Tot zover niets om je druk over te maken.
In het persbericht staat echter dat de bloemen van de planten patronen van elektrische signalen uitzenden en dat bijen de verschillende signalen van verschillende bloemen van elkaar kunnen onderscheiden. Dat is wel zeer bijzonder.
Tot nu toe weten we dat bijen zich op het aardmagneetveld oriënteren. Als ze nu ook nog elektrische veldpatronen kunnen detecteren, dan zou dat een reden te meer zijn om te begrijpen dat hun oriëntatievermogen verstoord kan worden door straling van zendmasten en mobieltjes.

Bees and flowers communicate using electrical fields, researchers discover

Flowers' methods of communicating are at least as sophisticated as any devised by an advertising agency, according to a new study, published today in Science Express by researchers from the University of Bristol. However, for any advert to be successful, it has to reach, and be perceived by, its target audience. The research shows for the first time that pollinators such as bumblebees are able to find and distinguish electric signals given out by flowers.

Flowers often produce bright colours, patterns and enticing fragrances to attract their pollinators. Researchers at Bristol's School of Biological Sciences, led by Professor Daniel Robert, found that flowers also have their equivalent of a neon sign – patterns of electrical signals that can communicate information to the insect pollinator. These electrical signals can work in concert with the flower’s other attractive signals and enhance floral advertising power.

Plants are usually charged negatively and emit weak electric fields. On their side, bees acquire a positive charge as they fly through the air. No spark is produced as a charged bee approaches a charged flower, but a small electric force builds up that can potentially convey information.

By placing electrodes in the stems of petunias, the researchers showed that when a bee lands, the flower’s potential changes and remains so for several minutes. Could this be a way by which flowers tell bees another bee has recently been visiting? To their surprise, the researchers discovered that bumblebees can detect and distinguish between different floral electric fields.

Also, the researchers found that when bees were given a learning test, they were faster at learning the difference between two colours when electric signals were also available.

How then do bees detect electric fields? This is not yet known, although the researchers speculate that hairy bumblebees bristle up under the electrostatic force, just like one’s hair in front of an old television screen.

The discovery of such electric detection has opened up a whole new understanding of insect perception and flower communication.

Dr Heather Whitney, a co-author of the study said: ''This novel communication channel reveals how flowers can potentially inform their pollinators about the honest status of their precious nectar and pollen reserves.''

Professor Robert said: “The last thing a flower wants is to attract a bee and then fail to provide nectar: a lesson in honest advertising since bees are good learners and would soon lose interest in such an unrewarding flower.

''The co-evolution between flowers and bees has a long and beneficial history, so perhaps it's not entirely surprising that we are still discovering today how remarkably sophisticated their communication is.''

The research was supported by the Leverhulme Trust.

www.bristol.ac.uk/news/2013/9163.html .

Hieronder de in Science online gepubliceerde samenvatting van het artikel, 21 febr. 2013

Detection and Learning of Floral Electric Fields by Bumblebees

Dominic Clarke*, Heather Whitney*, Gregory Sutton, Daniel Robert†
+ Author Affiliations

School of Biological Sciences, University of Bristol, Woodland Road, Bristol, BS8 1UG, UK.
↵†Corresponding author. E-mail:  .Robert@Bristol.ac.uk">D.Robert@Bristol.ac.uk
↵* These authors contributed equally to this study


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.

www.sciencemag.org/content/early/2013/02/20/science.1230883 .

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