Researchers at Emory University and the University of California, Berkeley have discovered that a microscopic roundworm known as Steinernema carpocapsae uses electrostatic induction to launch itself onto flying insects.
The study, published in PNAS, shows that the worm and its prey generate opposite electrical charges that attract each other, dramatically improving the worm’s odds of making contact midair.
Electricity in the Air
As insects fly through the air, the movement of their wings causes them to accumulate an electrical charge that can reach several hundred volts. This is enough to attract nearby dust, pollen, or, in this case, predators. The researchers found this charge also induces an opposite charge in the worm, creating an electrical attraction strong enough to pull the two organisms together.
“Higher voltage, combined with a tiny breath of wind, greatly boosts the odds of a jumping worm connecting to a flying insect,” said co-author Justin Burton, a physicist at Emory.
To capture the phenomenon in action, co-lead author Victor Ortega-Jiménez at UC Berkeley used high-speed microscopy to record the needle-tip-sized worms springing toward charged fruit flies. The insects were tethered by ultra-fine wires that allowed the researchers to precisely control their electrical potential.
“It’s very difficult to glue a wire to a fruit fly,” Ortega-Jiménez says. “Usually, it took me half an hour, or sometimes an hour.” Capturing clear footage also required hundreds of attempts, as each worm had to be coaxed to leap with just the right puff of air under carefully designed conditions.
Capturing the Invisible
Once the footage was complete, the team digitized the worms’ trajectories and analyzed them using a statistical algorithm known as Markov chain Monte Carlo (MCMC). This allowed them to simulate thousands of possible flight paths. They factored in the worm’s mass, launch velocity, and the insect’s voltage.
The model revealed that without any charge, only one in nineteen jumps would succeed. At roughly 800 volts, similar to the electric field around many flying insects, the worm’s probability of making contact soared to 80 percent.
The World’s Smallest High Jumpers
Even without the influence of static electricity, the nematode’s jumping ability is remarkable. When the worm detects an insect above, it coils into a loop and launches itself upward, reaching heights up to twenty-five times its own body length. For comparison, this would be similar to a person leaping over a ten-story building. While airborne, the nematode rapidly spins over a thousand times per second, increasing its likelihood of making contact with its target.
At the scale of these microscopic worms, factors like drag, airflow, and electrical charge interact to influence the success of this hunting mechanism. Researchers found that even a slight breeze moving at 0.2 meters per second increases a worm’s chances of making contact when combined with the higher voltages present from beating insect wings.
If the worm lands successfully, it will attempt to penetrate the insect’s body through a natural opening. The nematode will then release symbiotic bacteria that kill the host within forty-eight hours. The worm feeds on the bacteria and decaying tissue, reproducing inside the carcass until its offspring emerge to infect new prey. Since S. carpocapsae already plays a role in biological pest control, understanding the physics behind its behavior could make it even more effective in agricultural use.
Static Forces and Electrostatic Ecology
While static electricity is nothing more than a slight annoyance to humans, it serves as an important mechanism for many small organisms. Earlier research by Ortega-Jiménez showed that spider webs can use electrostatic attraction to capture insects. Bees and mites also depend on these forces to collect pollen or attach to hosts. Burton and Ortega-Jiménez recently reported that ticks can be lifted from the ground by the electrical charge in animal fur, a discovery that led directly to the current study on nematodes.
The team’s results align with predictions made by James Clerk Maxwell in the 19th century regarding electrostatic induction. “Sometimes being a scientist is like being an archaeologist,” said co-author Ranjiangshang Ran. “You dig through old ideas to find buried treasures in scientific history.”
These results point to the potential for a broader field of study, which the team calls ‘electrostatic ecology,’ aimed at understanding how electrical forces affect the behavior and evolution of small organisms.
“We live in an electrical world,” Ortega-Jiménez said. “Electricity is all around us, yet the electrostatics of small organisms remains mostly an enigma.”
“We’re developing the tools to investigate many more valuable questions surrounding this mystery,” he adds.
Austin Burgess is a writer and researcher with a background in sales, marketing, and data analytics. He holds a Master of Business Administration and a Bachelor of Science in Business Administration, along with a certification in Data Analytics. His work combines analytical training with a focus on emerging science, aerospace, and astronomical research.