Flaunting bizarrely blobby crowns, colorful helmets, or elaborately arching hats, treehoppers would fit right in at the most outrageous fashion show.
These tiny sapsuckers have long mystified researchers with their eccentric body shapes. Now, Bristol University ecologist Sam England and colleagues have proposed these wacky shapes may have been molded, at least in part, by an unexpected force: static electricity.
This is a charge that can arise when two surfaces with opposing polarities touch, creating an electrostatic discharge, which we can experience as a static shock.
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“Our study reveals that the extreme morphologies seen in animals such as treehoppers may increase their sensitivity to electrical stimuli,” England and team write in their paper.
Some of these treehopper spikes, bumps, antlers and head-ants, which all strangely arise from wing genes, could be explained by camouflage or mimicry. These include Cyphonia clavata, an ant mimic, and Umbonia crassicornis, which resembles just another thorn on a tree.
Yet, the staggering variety of morphology amongst the more than 3,000 species of treehoppers has remained puzzling.
So, England and team used computer modeling and found the odd morphology of different treehoppers could increase their reception of surrounding electrostatic stimuli by up to 100 times – just like a tall tree can attract lightning, England explains.
What’s more, by playing recorded static electricity from predatory wasps Mischocyttarus and Tetragonisca angustula, the researchers showed the treehopper (Poppea capricornis) moved away from them.
England and team also compared the electrostatic signals produced by stingless bees, which live harmlessly alongside treehoppers, and found they were very different in character from the predatory wasp signals.
“We used a device called a picoammeter, which detects tiny currents, to measure the electrostatic charge of the treehoppers, wasps, and bees as they flew, jumped, or dropped through it,” England writes on Bluesky.
“There are significant differences in the magnitude and polarity (positive or negative) of charges carried by the dangerous wasps vs friendly bees. So theoretically, treehoppers have the electrical information to distinguish friend from foe!”
Taken together, these findings suggest there may be a connection between electrostatic charge and the unique body shapes of treehoppers.
“If we can link treehopper shapes to certain aspects of their electrical ecology, like specific predators which approach from certain angles with particular static charges, this would really begin to strongly support our ideas around static electricity as an evolutionary driver,” says England.
“Our study provides the first evidence of the electrostatic sense potentially driving morphological evolution, but we can’t prove this just yet.”
This research was published in PNAS.
