The Physics of Tick Attraction: How Electrostatic Charge Enables Ticks to Reach Hosts Across Air Gaps – and the Actionable Insights This Provides
In 2023, researchers Sam England, Katie Lihou, and Daniel Robert from the University of Bristol showed that ticks are passively attracted to animal host surfaces by electrostatic forces (PMID: 37392744). In other words, a tick waiting on the edge of a blade of grass is not solely limited to a host physically brushing up against it to attach. If there's an air gap between them and the host, ticks have no mechanical means of jumping across that gap. However, the tick can be pulled across the air gap if electrostatically charged animal fur passes by it, with measured distances of several millimeters to centimeters. This is a small distance to us, but compared to the tick's body, it would be like flying across a distance of several flights of stairs.
Terrestrial animals naturally accumulate electrostatic charges as they move through their environments and are known to carry surface potentials up to tens of thousands of volts. This happens because of the triboelectric effect — the process in which electrons transfer between two materials with different tendencies to gain or lose electrons. The further apart the two materials are on the triboelectric chart (the greater their difference in affinity to gain or lose electrons), the greater the voltage that will build up with their friction. This effect is the basis for everyday static electricity. As a rabbit's fur brushes against the grass, or as your socks brush against the carpet, this effect is at play.
As a buildup of positive or negative electrical charge develops via the triboelectric effect (static electricity), it generates an electric field that radiates into the surrounding air around the organism. When that field reaches a tick, it induces an electrical polarization within the tick's body. The host's electric field redistributes the charged ions in the tick's body fluid: if the host is positively charged, the tick's negative ions shift toward the host while its positive ions are pushed to the far side. The tick is now electrically polarized, and this generates an electrostatic force that pulls it toward the host, across open air.
The voltage required to pull a tick scales linearly with the size of the gap: a roughly constant field strength (approximately 260–290 kV/m) must be reached, so a more highly charged host can meet that threshold across a proportionally larger gap. The greater the host's surface voltage, the longer its reach. At just 750 volts (a conservative estimate for a moving vertebrate) 75% of ticks in the study were lifted across a 3 mm gap, with a median lift-off time of under a second. Human surface voltages, which can reach tens of thousands of volts, can attract ticks across air gaps of several centimeters with no physical contact required. This means that the greater your static charge buildup, the more ticks will be electrostatically pulled to you as you walk past them. Meanwhile, the lower your own surface voltage — the closer you sit to the earth's potential — the weaker the field you project, the less the tick is polarized, and the more it has to rely on actual physical contact to reach you.
So how can we apply the physics of tick attraction to our daily lives and use the information to inform our decision-making to decrease the rate at which we collect ticks on our bodies?
How much charge your body carries depends on what materials generate friction against your skin and whether that charge has a pathway to dissipate.
If you wear rubber-soled shoes, as rubber is an insulator, you block the physical transfer of electrons between you and the surface of the earth, so the static charge you generate by brushing against surfaces has no path to dissipate and instead accumulates on your body. The voltages involved are substantial. England and colleagues note that humans can accumulate surface voltages as high as ~30,000 V, with the exact value governed largely by humidity. The drier the conditions, the more charge builds. This accumulated charge creates an electric field that radiates outward from the body in all directions, and if that field reaches a tick on a nearby blade of grass and polarizes it, that is what generates the attractive force.
In contrast, if you were barefoot or wearing leather-soled or purpose-made grounded shoes, your body would be electrically connected to the earth, and accumulated charge would continuously drain away rather than build, keeping your surface voltage very low. A hiker in grounded shoes lowers their body voltage, which weakens the field reaching the tick, induces less polarization in the tick's body as they pass, and so reduces the chance that the tick is electrostatically pulled across the air gap.
At the same time, many people wear synthetic clothing made of polyester, which sits toward the strongly electron-acquiring end of the triboelectric series. Every movement of your skin against polyester transfers electrons from your skin onto the fabric, leaving your body surface progressively more positively charged and the polyester more negatively charged.
When it comes to the electrostatic attraction of the tick across the air gap, the charge — negative or positive — doesn't matter. What matters is just the strength of the field cast by the host passing by: any sufficiently strong field induces polarization in the tick's body, propelling it toward the host. So wearing electron-stealing polyester while also being physically ungrounded from the surface of the earth builds up even greater static charge on your body, which further increases the ability of ticks to be passively attracted across even larger air gaps to you. Cotton, in contrast, sits near the neutral point of the triboelectric series. It does not have the strong electron-stealing effect on your skin that polyester does and will generate minimal charge.
Picture two people walking through the same field with the same number of ticks in it. Person A is wearing rubber-soled shoes and polyester clothing, generating a buildup of static charge with no discharge path, while Person B is wearing cotton clothing and grounded shoes, generating little static charge and maintaining a near-zero voltage difference with the ground. Person A is more likely to attract ticks, not only via physical contact but by drawing them in via electrostatic propulsion. Person B is less likely to attract ticks electrostatically and is more reliant on direct physical contact.
Applying this information doesn't make anyone tick-proof, but it addresses a specific, physics-based variable that can increase or decrease the rate at which ticks are drawn to your body and, in turn, your exposure to the bites that transmit tick-borne illness.
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REFERENCES
England SJ, Lihou K, Robert D. Static electricity passively attracts ticks onto hosts. Current Biology. 2023;33(14):3041-3047.e4. [DOI: 10.1016/j.cub.2023.06.021](https://doi.org/10.1016/j.cub.2023.06.021) | [Full text: PMC7616434](https://pmc.ncbi.nlm.nih.gov/articles/PMC7616434/)
Ortega-Jimenez VM, Gardner AM, Burton JC. Ticks' attraction to electrically charged hosts. Trends in Parasitology. 2023;39(10):806-807. [DOI: 10.1016/j.pt.2023.08.001](https://doi.org/10.1016/j.pt.2023.08.001)
