Chemical sprays alter the electric field around flowers for up to 25 minutes after exposure. This is according to a study published today in PNAS Nexus. This effect lasts much longer than natural fluctuations. Such as those caused by wind, and reduces bee feeding effort in nature.
Dr Ellard Hunting of Bristol’s School of Biological Sciences and his colleagues noticed that fertilisers had no effect on vision or smell. So, they set out to electrically manipulate flowers to mimic the electrical changes caused by fertilisers and pesticides in the field. This demonstrated that bumblebees could detect and distinguish between the small and dynamic electric field alterations caused by chemicals.
“We know that chemicals are toxic,” said Dr. Ellard Hunting. “But we know very little about how they affect the immediate interaction between plants and pollinators.” Flowers emit a variety of cues that attract bees and encourage feeding and pollination. Bees, for example, use cues such as flower odour and colour to identify plants, but they also use electric fields. As a result, agrochemical application can distort floral cues and modify behaviour in pollinators such as bees.”
Furthermore, other airborne particles such as nanoparticles, exhaust gases, nano-plastics, and viral particles may have similar effects. It affectes a diverse range of organisms. These organisms rely on the electric fields that are present almost everywhere in the environment.
“What makes this study important is that it’s the first known example of anthropogenic ‘noise’ interfering with a terrestrial animal’s electrical sense,” co-author Sam England said. It’s similar to how motorboat noise impairs fish’s ability to detect predators, or how artificial light at night confuses moths. Fertilisers are a source of noise for bees trying to detect floral electrical cues. This broadens our understanding of the many ways in which human activity harms the natural world. It is depressing. But it will hopefully allow us to introduce or invent solutions to prevent the negative effects that these chemicals may be having on bees.”
“The fact that fertilisers affect pollinator behaviour by interfering with the way an organism perceives its physical environment offers a new perspective on how human-made chemicals disturb the natural environment,” Dr Ellard Hunting added.
The European Research Council and the Swiss National Science Foundation funded the project.