The mechanisms of electroreception in bees

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The ecological partnership between flowers and bees is profound; flowers evolved spectacular displays of colours and fragrant volatiles to attract pollinators, in particular bees, to secure pollen transfer and fertilisation. Many flowers include nutritious nectar as a special reward. Both bee and flower benefit from this remarkable example of cooperation. Thus, bees can see and smell flowers, but is that all? Our research changed its path when we marveled at the fact that a flower's pollen is capable of jumping towards an approaching bee and sticking to it. Driven by electrostatic forces, the pollen is transported from flower to flower. But is this the only way electricity can enhance pollination? Following these observations, a simple question came to our minds: does the bee know anything about the presence of this electrostatic field? Recently, we reported that bumblebees (Bombus terrestris) can detect and learn about floral electric fields. These fields are in fact floral cues, complementing colour, scent, temperature, humidity and shape. Floral fields are affected by the visit of bees, which are also electrically charged. Like visual cues, floral electric fields exhibit variations in pattern and structure, which can be discriminated by bumblebees. We also showed that electric field information can improve a pollinator's memory of floral rewards. Because floral electric fields can change within seconds, their detection may facilitate rapid communication between flowers and their pollinators. Yet, how bees detect floral electric fields remains unknown. The goal of the proposed research is to identify the sensory mechanisms by which a bee detects electric fields. Do bees have a dedicated electric sensory organ, like many animals have dedicated ears to detect sounds? We hypothesise that bees use the fine hairs on their bodies to sense the presence of floral electrostatic fields. This is similar to the sensation we experience from the hairs on our arm rising in front of an old television set. We will measure the deflection of bee hair and record the activity of sensory neurones at their base. We will also train bees to recognise different electric fields and, after impairing the bending of these hairs, evaluate their recognition ability. Using mathematical modelling and laser vibration technology, we will also establish the kind of electric fields that bees are in effect sensitive to. Are they only sensitive to floral fields? This work will describe an entirely novel sense. The role this electrical sense plays in the life of bees including their mutualism with flowers, is still poorly understood. Do other important pollinators, such as flies, beetles and moths also sense floral electric fields? Our work will also change the way we understand our environment and its complexity, adding an electric component. Currently we are blind to this electrical ecology; yet this research project aims at providing ways to visualise this thus far elusive part of the natural world. Potentially, novel electrical measurement techniques, perhaps bio-inspired, will emerge from our investigations on detection of weak and local electric fields. As such, the interest of technologists may also be important to the long term continuation and diversification of our research and its impacts. Also, our research will enable further questions to be asked about the possible negative or positive, but currently unknown, impacts of man-made electric fields on pollinators, and other organisms, including plants, and the environment. As bees provide important and valuable pollination services for many crops consumed by humans, it may be very timely to better understand the biology of bees, and ensure they can remain safe and healthy in a rapidly changing and uncertain environment.