At first glance, it’s a wonder that jumping parasitic nematodes exist at all. To reproduce, these minuscule creatures—roughly the size of a pinpoint—hurl themselves up to 25 times their body length to land on a flying insect as it zooms overhead. Given that wind, gravity and air resistance all stand in the way of a bull’s-eye, the worms’ chances seem poor. But new research shows there’s a force working to their advantage: static electricity.
At human scale, static electricity is little more than a curiosity. You walk across the carpet, friction transfers electrons from the floor to your socks, and you receive a mild zap when the electrical imbalance rights itself by discharging to the first metal object you touch—ouch. But similar processes hold tremendous sway in the teensy world of insects. According to a recent study in the Proceedings of the National Academy of Sciences USA, the mere beating of insect wings generates enough positive charge to pull an oppositely charged, airborne nematode inexorably toward its unlucky host, whose decaying flesh will soon shelter the parasite’s eggs. The worms seem to have outsourced their accuracy to these electric tractor beams. “They don’t need to be precise” when they jump, says study co-author Víctor Ortega-Jiménez, a biologist at the University of California, Berkeley, “just close enough to be attracted.”
A nematode leaps and floats on the wind.
Victor Ortega Jimenez/University of California, Berkeley
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This study is the latest in a line of experiments that, over the past decade, have illuminated the exotic physics that govern small animals’ lives. In 2013 researchers reported that bees can sense electric fields around flowers and use that information to guide their foraging decisions. Around the same time, Ortega-Jiménez and a colleague discovered that spiderwebs deform when positively charged insects fly by, bulging out to ensnare them. In 2023 a group of researchers in the U.K. found that ticks are passively attracted to furry hosts, whose fluffy coats accumulate electrons.
The 2023 study was co-led by Sam England, now a postdoc investigating sensory ecology at Berlin’s Natural History Museum. Given the precedent in ticks, he wasn’t surprised to learn from the new study that nematodes have also harnessed electricity for parasitic purposes. But whereas ticks sit around waiting, worms “actively input force into the attraction” by jumping, he notes, becoming agents of their own grisly destiny. 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. The work “helps us better connect all of these new and exciting discoveries in electrostatic ecology with the wider physics of ecological interactions,” he says.
A nematode winds up for its leap.
Victor Ortega Jimenez/University of California, Berkeley
By adjusting the voltage sent through copper wire to living fruit flies—they don’t generate their own electricity unless they’re flying—Ortega-Jiménez tested the effect of static charge on airborne nematodes. The trend was clear: the higher a fly’s electric potential, the more likely nematodes were to latch on when they flung themselves into the air. Given zero static, they almost always missed; at higher voltages they latched on more than half the time. With the help of study co-author Ranjiangshang Ran, a postdoc studying fluid mechanics at Emory University, the team added hundreds of thousands more simulated jump trajectories and found that when the virtual voltage reached 800 V, the digital worms were almost unstoppable. In simulations with a gentle, buoyant breeze to keep them aloft long enough for static to take over, their overall success rate soared to more than 70 percent, including for launches that were in exactly the wrong direction.
Nematode launches and is pulled toward a charged fruit fly.
Victor Ortega Jimenez/University of California, Berkeley
For nematodes, a jump is no small feat. If they don’t stick the landing, these aerial hunters can quickly dry out, starve or become hunted themselves. So their odd survival strategy depends on static electricity—without its reassuring pull, they most likely would never have left the ground. “It wouldn’t make sense for them to evolve this jumping mechanism without the presence of electrostatics,” Ran says. Other animals may not be so fully reliant on this force. But England suspects that as the list of electrically sensitive species grows, we’ll find that electrostatic effects “play countless roles” throughout the natural world. “Their importance to ecosystems as a whole,” he says, “has probably been historically quite underestimated.”