The mechanisms and function of bumblebee electroreception

Our research has shown that bumblebees can detect the weak electrostatic fields around flowers. Such electric fields constitute new floral cues, and enhance a bee's capacity to learn the difference between two floral colours. Electric fields thus appear to play a role in plant-pollinator interactions. Several fundamental questions arise from these findings. What is the structure and ultimate relevance of these flower- and bee-generated electric fields? Central to this project is the question of how bees measure floral and environmental electric fields. What is the sensory mechanism for electroreception? Can bees measure their own field? This studentship aims at investigating the sensory basis of bee electroreception, with regard to characterising for the first time the type and range of electrical information the bee's sensory system evolved to detect.
The project aims at establishing the bee's sensitivity to weak electrical fields in both laboratory and field experiments. In the lab, hypotheses will be tested as to how fine hairs covering the bee's body detect e-fields. Preliminary mechanical and electrophysiological evidence (Sutton, Clarke, Robert lab) indicates that cranial hairs can sense electric fields. Alternative hypotheses will address the putative role of antennae, wings and other hairs in electroreception.
Electroreception will be behaviourally tested with training (Whitney lab) and psychophysical tests using the proboscis extension reflex (Sutton, Robert). Measuring electrics in natural flowers and then simulate them in artificial e-flowers (Robert, Whitney labs) will allow determining the structure, shape and magnitude of the electric fields bees can detect. Mathematical modelling (Multiphysics Finite Element Analysis) will be used to investigate the structure and diversity of weak electric fields around bees, flowers and from the atmospheric environment (Robert, Shallcross) to inform sensory experiments above. The large scale foraging trips of bees in the open environment will be monitored using radar techniques (Reynolds, Chapman, Haughton, Osborne), in conjunction with measurements of atmospheric potential gradients and weather conditions. Electric fields may affect, perhaps even facilitate chemical signalling between herbivores and plants (Birkett). Pollinator and/or parasitoid behavior may in turn initiate floral electric fields, which may alter plant semiochemistry and therefore relationship to insects.
This project will provide initial interdisciplinary training. Two rotations are planned; one in the Robert, Sutton, Shallcross and Whitney labs already collaborating in Bristol, to learn mechanical, electrophysiological, modelling, atmospheric physics and behavioural techniques. The other rotation will be at Rothamsted Research (radar team) and used to become familiar with radar techniques and their application to tracking bees and measuring atmospheric electric fields. Initial training in study of plant signalling and insect olfaction will be provided (biological chemistry Birkett group). The integration of the required skill sets during the rotations will be monitored by regular meetings with PI, Co-Is, student, and associated postdocs. The student will be fully integrated in the SWBIO course programme and those offered by the School of biological sciences. In support of this studentship, a BBSRC grant application (Robert, Whitney, Shallcross) in its final stage of evaluation, will provide support, including two postdocs, to this studentship. Additional support is from Dr. G. Sutton, recently awarded a Royal Society University Research Fellowship at Bristol.