Cosmic lobsters and electric bees
DOI: 10.1063/PT.5.010212
Like other science editors I scan a lot of press releases. Some of the titles catch my eye, either because their writers opted for something witty or cute (“Sweeping the dust from a cosmic lobster” ) or because the science in the press release, even when soberly summarized, is alluring (“New imaging device is flexible, flat, and transparent” ).
A press release I encountered last Tuesday fell into the second category. “Sparks fly between flowers and bumblebees” flagged one of the papers previewed in Science magazine’s weekly press release. The notion that flowers have electrostatic fields and that bumblebees can detect the fields was so unexpected and intriguing that I promptly downloaded the paper .
As should be the case for papers in general science journals, the introduction proved to be accessible and informative. The authors, led by Daniel Robert of the University of Bristol in the UK, summarized evidence from the past 30 years that electricity plays a role in pollination.
A bumblebee caught in the act of collecting pollen from what looks like a lupin. CREDIT: Nigel Raine
My interest piqued, I wanted to read those early papers, especially one by Sarah Corbet, Jimmie Beament, and Dan Eisikowitch, which appeared in 1982 in volume 5 of Plant, Cell & Environment. Here is its abstract:
The measurements of Yes’kov & Sapozhnikov (1976) suggest that electrostatic potentials on foraging honeybees can reach hundreds of volts. Pollen grains of oilseed rape, Brassica napus L., subjected experimentally to potentials of this order, jumped a distance that increased approximately as the square of the voltage, between two pin electrodes on which, in some experiments, were impaled an anther or stigma of oilseed rape or a freshly-killed honeybee. Most floral surfaces were insulated, but there was a low-impedance path to earth via the stigma, and the electrostatic field due to an approaching charged bee must therefore concentrate there. Thus, if electrostatic potentials of this magnitude occur in nature they may increase the chance that pollen from bees will reach the stigma rather than other floral surfaces, as well as enabling pollen to jump from anther to bee and from bee to stigma across an air gap of the order of 0.5 mm.
As far as I can tell, the paper was the first to report that pollen is electrically charged. But I couldn’t evaluate its priority because the paper and others that Robert cited in his Science paper were behind their respective journals’ paywalls. That observation isn’t a criticism. Most of Physics Today‘s content is similarly walled off to nonsubscribers. Still, the paywalls did rather restrict my investigative efforts.
Sir James “Jimmie” William Longman Beament
But those efforts weren’t wholly in vain. My various online searches led me to John T. Green’s charming biographical memoir of his friend and former colleague, Jimmie Beament, the electric pollination pioneer.
Sir James “Jimmie” William Longman Beament (1921–2005) spent most of his productive and distinguished career at the University of Cambridge, where he had earned his bachelor’s degree. His first research project, and the one from which his career sprang, was to investigate the physical basis of insects’ ability keep their bodies from drying out.
Of course I can’t be sure, but it’s my hunch that if anyone had asked Beament why, in the 1940s, he was studying insect desiccation, he might have replied, “Because it’s interesting!” He couldn’t have known that he would go on to develop an insect-inspired wax that keeps bananas fresh on sea voyages, dispensing with the need for expensive refrigeration. Or that he’d solve the mystery of why tilapia weren’t finding enough food to eat in Ghana’s Lake Volta.
Beament was evidently so fascinated by the surfaces of insect bodies and eggs that he sought collaborations with physicists to study them. He was among the first entomologists to look at insects through an electron microscope. In 1958 he and Ken Machin, a radio astronomer, developed an electronic thermostat accurate to 0.01 K—and used it to discover, among other things, that locusts are coated with a wax that becomes permeable at 39 °C, thereby allowing evaporation to cool their muscles in very hot weather.
Soon after I read about Beament, I received a message from one of the fans of Physics Today‘s Facebook page . He sought my advice on whether he should pursue a graduate degree in materials science or physics. I told him he should choose a field in either discipline that would hold his interest through and after graduate school, just as Beament did.