Scientists have discovered that a minuscule parasitic nematode employs static electricity to leap onto flying insects, boosting its hunting success dramatically. The research, involving high-speed imaging and mathematical models, reveals how electrostatic forces enable the worm to bridge gaps in midair. This finding highlights the role of invisible electrical interactions in small organisms' survival.
The nematode Steinernema carpocapsae, a parasitic worm found in soils worldwide except the poles, can jump up to 25 times its body length—equivalent to a human leaping over a 10-story building—while rotating at 1,000 times per second. When sensing an insect overhead, it curls into a loop and launches itself. If successful, it enters the host through a natural opening, deposits symbiotic bacteria that kill the insect within 48 hours, and feeds on the bacteria and tissue to lay eggs.
Researchers from Emory University and the University of California, Berkeley, published their findings in the Proceedings of the National Academy of Sciences. They used high-speed cameras capturing 10,000 frames per second to record the worm's trajectories toward charged fruit flies. Co-author Justin Burton, an Emory physics professor, explained: "We've identified the electrostatic mechanism this worm uses to hit its target, and we've shown the importance of this mechanism for the worm's survival. Higher voltage, combined with a tiny breath of wind, greatly boosts the odds of a jumping worm connecting to a flying insect."
The key mechanism is electrostatic induction: an insect's wings generate an electric field of several hundred volts as they move through the air, inducing an opposite charge in the worm for attraction. Victor Ortega-Jiménez, a UC Berkeley biomechanics assistant professor who led experiments, noted: "You might expect to find big discoveries in big animals, but the tiny ones also hold a lot of interesting secrets."
Mathematical modeling by Ranjiangshang Ran showed that without electrostatics, only one in 19 jumps succeeded. A 100-volt charge yielded less than 10% success, while 800 volts raised it to 80%. Even a faint breeze of 0.2 meters per second enhanced outcomes further. The model aligned with a 1870 prediction by physicist James Clerk Maxwell.
This work pioneers 'electrostatic ecology,' building on prior discoveries like bees using static to gather pollen or spiders exploiting charges in webs. S. carpocapsae is used in biological pest control, and these insights could improve its agricultural applications. As Ortega-Jiménez said: "We live in an electrical world, electricity is all around us, but the electrostatics of small organisms remains mostly an enigma."