Static electricity may help butterflies and moths gather pollen on the fly

Birds do it. Bees do it. Even butterflies and moths do it.

As lepidopterans flutter their wings, friction with the air causes them to accumulate static electricity — enough to potentially pull pollen from nearby flowers, new research suggests.

Ecologists Sam England and Daniel Robert measured the electrostatic charges of 269 butterflies and moths representing 11 species. The amount of charge varied across species, probably due in part to differences in body surface area. But computer simulations showed that the average charge of a butterfly, roughly 50 picocoulombs, is strong enough to move 100 pollen grains at least six millimeters, the scientists report July 24 in the Journal of the Royal Society Interface. Given that flowers also have their own electric pull, this suggests that lepidopterans may be able to pollinate flowers without having to land on the blooms.

The team also found that the polarity of a charge and its strength seemed related to benefits in a species’ environment. For instance, the higher a positive charge — found to be common in lepidopterans from temperate regions — the better some insects can detect flowers’ electric fields, which can relay information about how much nectar the plants have (SN: 2/21/13). Meanwhile, lepidopterans from the tropics were more likely to have a negative charge, which might help cloak them from detection by predators (insect predation is higher in the tropics than in other climates).

“The fact that we are seeing these correlations with ecology points to the fact that it might be a trait that evolution is acting on,” says England, of the Natural History Museum in Berlin. He did the work with Robert while both were at the University of Bristol in England.

Butterflies and moths are just the latest additions to the list of organisms capable of gathering pollen electrostatically. Previous research has observed the phenomenon in bees and hummingbirds (SN: 1/8/77). The diversity in this small but growing group suggests that electrostatic pollination could be more widespread in the animal kingdom than previously thought, England says.