Electrostatic Pulling and Aerial Drifting Influence Parasite-Host Relationships*

Small parasites, such as nematodes, are prone to be detached and drifted for long distances by moderate winds. At the same time, these submillimeter worms can be easily detached and attracted towards distant charged bodies via electrostatic induction. However, to date, it is unknown how both aerodynamics and electrostatic forces can impact parasites-host interactions. We found that entomopathogenic nematodes can travel long horizontal distances when drifting in the air, depending on flow speed and jumping kinematics. In still air, jumping worms were passively attracted to an electrically charged insect, or even to a water droplet. We discovered that these tiny parasites can reach more distant charged bodies while carried by the wind, than when in still air. Because worms' trajectories are determined by electrostatic and aerodynamic forces, thus their charge, launch angle, and jumping velocity can be inferred using Bayesian inference. Our results suggest that aerial drifting and electrostatic pulling can significantly increase the likelihood of physical contact and attachment of a parasite to its host. Furthermore, nematode's attraction to charged rain droplets can contribute to their survival in the troposphere.