Butterflies use electric charge to pull pollen without touching flowers: Study

Researchers from the University of Bristol found that butterflies and moths attract pollen using electricity and that electric charges are even evolutionary.

Biologists understood that some insects such as bees and hummingbirds create electric charges in the air, and they even suspected that it improved their ability to attract pollen.

“However, it wasn’t known whether this idea applied to the wider array of equally important pollinators such as butterflies and moths,” according to lead author Dr. Sam England in a press release.

“So, we set out to test this idea and see if butterflies and moths also accumulate charge, and if so, whether this charge is enough to attract pollen from flowers onto their bodies.”

Their findings provide an even clearer picture of the greater role static electricity plays in pollination. It may be “very powerful and widespread,” Dr. England said.

Anyone who has ever received an electric shock or rubbed a balloon against their clothes to stick it to a wall has had contact with static electricity. However, this phenomenon enables a contactless exchange between plant and pollinator.

As everything is made up of charges, protons being positive and electrons having a negative charge, an imbalance between negative and positive charges in an object produces static electricity.

The study into static electricity in butterflies and moths

In this study, Bristol researchers studied this intriguing effect in 269 butterflies and moths from 11 different species across five continents and ecological niches. They compared them to assess if ecological factors correlated with their charges, according to the press release, to understand if static electricity was an evolutionary trait.

“By establishing electrostatic charging as a trait upon which evolution can act, it opens up a great deal of questions about how and why natural selection might lead to animals benefiting or suffering from the amount of static electricity that they accumulate.”

They discovered that “ butterflies and moths accumulate so much static electricity when flying, that pollen is literally pulled through the air towards them as they approach a flower.”

“This means that they don’t even need to touch flowers in order to pollinate them, making them very good at their jobs as pollinators, and highlighting just how important they might be to the functioning of our flowery ecosystems,” Dr. England continued.

Secondly, they confirmed that the amount of electricity varied from species to species depending on their behavior and environment, whether they’re nocturnal, for example, or live in tropical conditions. It suggests that evolution plays a role in this trait, and that it’s necessary on a fundamental level.

Tapping into these inner mechanisms might open doors to creating technologies to artificially increase electrostatic charges or pollinators or pollen, according to the press release, in order to improve pollination rates in natural and agricultural settings, which could have a profound effect on the environment as dwindling bee populations, even, have concerned scientists in the age of climate change.

The electric conversation between pollinators and flowers

Bee Culture explained that flowers are electrically connected to the earth, and they pick up a negative charge through electrostatic induction. Bees create a positive charge, and this seems to support an efficient exchange between plant and animal.

An academic paper on the subject presented the theory around the role of electrostatic forces that enabled the contactless accumulation of pollen, but this is the first evidence that suggests that the static electricity an animal accumulates is a trait that can be adaptive, and thus evolution can act upon it by natural selection, the press release concludes .

For Dr. England, the next step in this research would survey a wider set of species and “see how much static electricity they accumulate and then look for any correlations with their ecology and lifestyle. Then we can really begin to understand how evolution and static electricity interact!”

The finding was published in the Journal of the Royal Society Interface .