Bad for bees: Fertilizers change electric fields around wildflowers

By Mark Waghorn via SWNS

Pesticides and fertilizers change electric fields around wildflowers - stopping bees from homing in, according to new research.

The crop chemicals put them off their favorite foods, changing their foraging and hindering the extraction of nectar.

Chemical sprays cause the numbers of these vital insects to plummet, threatening biodiversity and human food supplies.

Pollinators are drawn in by bright colors, patterns on petals, aromatic smell and electricity in the air.

Flowers have their own distinctive electric fields governed by their unique shape and how often they have been visited.

Lead author Dr. Ellard Hunting, of Bristol University, said: "That fertilizers affect bee behavior by changing the way it experiences its physical environment gives a new perspective on how humans disturb the natural environment."

"Imagine yourself not being able to distinguish apples from tomatoes because someone sprayed some chemicals in the vegetable department.

"This may be relevant for all organisms that use the electric fields that are virtually everywhere in the environment."

Farmers protect plants by spraying them with cocktails of molecules that are toxic to critters.

Their widespread use in agriculture and horticulture is a substantial source of pollution - and has been linked to dramatic reductions in bee populations.

Many carry an electric charge designed to adhere to plants, potentially altering the physical force.

Now the first study of its kind has found it can distort floral cues and disturb the actions of bees.

The phenomenon will probably apply to other pollinators such as wasps, beetles, butterflies and moths.

Dr. Hunting's team observed vision and smell were unaffected but there was a response in the electric field surrounding the flower.

In experiments, they sprayed cut flowers with positively charged, colored particles released as an aerosol, then scanned them.

The electric field changed up to 25 minutes - a period substantially longer than natural fluctuations such as those caused by wind.

It aligns with declines of about 20 minutes in bee-feeding efforts found in nature. The plant had the same lasting response during rain simulations.

It suggests the effect persists beyond the single use of chemicals. In other tests, bumblebees were less keen to land on a flower that had been electrically manipulated.

Dr. Hunting said: "This showed bumblebees were able to detect and discriminate the small and dynamic electric field alterations that are caused by agricultural chemicals."

The results published in the journal PNAS Nexus shed fresh light on how human-made chemicals disturb the natural world.

They emphasize the importance of the senses used by insects to understand and learn about their environment.

As far back as the 1970s, botanists suggested electric fields enhance the attraction between pollen and pollinators.

Many animals can sense electric fields, including sharks and rays, electric fish, at least one species of dolphin, and the platypus.

A recent scientific review of insect numbers around the world suggested that 40% of species were undergoing "dramatic rates of decline."

This has detrimental effects on our ecosystems and food supplies.