Static Electricity Helps Parasitic Nematodes Leap onto Insects

Watch these parasitic worms use static electricity as a tractor beam

By Cody Cottier edited by Sarah Lewin Frasier

At first glance, it is surprising that parasitic nematodes exist. To reproduce, these tiny creatures – about the size of a pin – must jump 25 times their body length and land on a flying insect flying over its head. Since wind, gravity, and air resistance all stand in the way of a target, the worms’ chances seem low. But new research shows there’s another force working in their favor: static electricity.

On a human scale, static electricity is little more than a curiosity. You walk on the carpet, the friction transfers electrons from the floor to your socks, and you get a slight zap as the electrical imbalance redresses, discharging onto the first metal doorknob you touch – ouch. But similar processes exert enormous influence in the tiny world of insects. According to a new study in Proceedings of the National Academy of Sciences USAthe simple flapping of an insect’s wings generates enough positive charge to inexorably attract an oppositely charged airborne nematode toward its unlucky host. The worms seem to have outsourced their precision to these electric tractor beams. “They don’t have to be precise” when they jump, says study lead author Víctor Ortega-Jiménez, a biologist at the University of California at Berkeley, “just close enough to be attracted.”

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It’s the latest in a series of experiments that over the past decade have shed light on the exotic physics that governs the lives of small animals. In 2013, researchers reported that bees could detect electric fields around flowers and use that information to guide their foraging decisions. Around the same time, Ortega-Jiménez discovered that spider webs distort when positively charged insects pass by, bulging to trap them. More recently, in 2023, a group of British researchers discovered that ticks are passively attracted to furry hosts, whose fluffy coats accumulate electrons.

The 2023 study was led by Sam England, now a postdoctoral fellow in sensory ecology at the Natural History Museum in Berlin. Given the precedent with ticks, he wasn’t surprised to learn from the new study that nematodes also exploit electricity for parasitic purposes. But while the ticks wait, the worms actively “inject force into the attraction” by jumping, he notes, becoming agents of their own grisly fate. England was also impressed by how Ortega-Jiménez and his colleagues integrated the effects of other forces, such as air resistance, with those of static electricity in the new research. This work “helps us better connect all of these new and exciting discoveries in electrostatic ecology to the broader physics of ecological interactions,” he says.

To test the effect of static charging on airborne nematodes, Ortega-Jiménez attached live fruit flies to a live copper wire and adjusted the voltage to between 100 and 700 volts, comparable to that generated by insects in nature. (Because they weren’t flying, they weren’t generating their own charge.) Then he released the worms, letting them lunge at their electrified prey. The trend was clear: the higher a fly’s electrical potential, the more likely nematodes were to attach to it. With zero static, they were almost always missing; at higher voltages they locked more than half the time.

But coaxing nematodes is tricky and time-consuming, so Ortega-Jiménez collaborated with Ranjiangshang Ran, a postdoctoral fellow studying fluid mechanics at Emory University, who has performed computer simulations of thousands of other jumping trajectories. When the virtual voltage reached 800 V, the digital worms were unstoppable: In simulations with a light, sustained breeze to keep them aloft long enough for static to take over, their overall success rate jumped to more than 70 percent, including launches that were in exactly the wrong direction.

For nematodes, a jump is no small feat. If they fail to land, these aerial hunters can quickly dry out, starve, or become hunted themselves. Thus, their entire survival strategy depends on static electricity: without its reassuring attraction, they would probably never have left the ground. “It wouldn’t make sense for them to evolve this jumping mechanism without the presence of electrostatics,” says Ran. Other animals may not rely on this strength as much. But as the list of electrically sensitive species grows, England thinks we’ll discover that electrostatic effects “play countless roles” in the natural world. “Their importance to ecosystems as a whole,” he says, “has probably historically been quite underestimated.”

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