Static Electricity Causes Ticks to be Attracted to Hosts

Researchers at the University of Bristol have found that ticks could be drawn across air gaps several times larger than themselves by the static electricity that naturally builds up on their hosts.

Since ticks are unable to jump, this is the only way they would be able to establish touch with hosts that are out of reach for their tiny legs. This most certainly boosts their effectiveness at identifying hosts to parasitize.

The research results published in Current Biology are the first case in which static electricity has been linked to an animal’s attachment to another animal.

Lyme disease is just one of many diseases that ticks can spread and can be fatal or severely impair the lives of many people and animals. As a result, attempting to lessen ticks’ capacity to adhere to humans and the animals they depend on has significant societal and economic benefits.

We knew that many animals, including humans, can accumulate quite significant electrostatic charges. We see this when we get a static shock after bouncing on a trampoline, or when rubbing a balloon on our hair, for example. But this electrostatic charging also happens to animals in nature when they rub against objects in their environment like grass, sand, or other animals.”

Sam England, Study Lead Author, School of Biological Sciences, University of Bristol

England added, “These charges are surprisingly high, and can be equivalent to hundreds if not thousands of voltsmore than you get out of your plug sockets at home! Importantly, static charges exert forces on other static charges, either attractive or repulsive depending whether they are positive or negative. We wondered whether the static charges that mammals, birds, and reptiles naturally accumulate could be high enough that parasitic ticks could be lifted through the air by electrostatic attraction onto these animals, therefore improving their efficiency at finding hosts to feed on.”

The theory was first put to the test by the team by introducing statically charged rabbit hair and other items close to ticks and watching to see if the ticks were drawn to them.

They conducted further research after observing the ticks being easily drawn through air gaps of several millimeters or centimeters (the equivalent of someone jumping up several flights of stairs) by these charged surfaces.

England added, “First, we used previous measurements of the typical charge carried by animals to mathematically predict the strength of the electric field that is generated between a charged animal and the grass that ticks like to sit on and wait for hosts to pass by.”

He continued, “Then, we placed ticks underneath an electrode, with an air gap in between, and increased the charge on the electrode until the ticks were attracted onto the electrode. By doing this we were able to determine the minimum electric field strength at which the ticks could be attracted. This minimum electric field was within the order of magnitude predicted by the mathematical calculations of the electric field between a charged animal and grass; therefore, it is likely that ticks in nature are attracted onto their hosts by static electricity.”

These results have several other, broader ramifications and potential uses. First, the phenomena could indicate a universal technique for animals to establish contact with and attach to one another since it likely applies to many other parasitic species, such as mites, fleas, or lice, that wish to make contact with and attach to their hosts.

Beyond its purely scientific ramifications, the discovery makes it possible to develop new technologies, such as anti-static sprays, to reduce tick attacks in people, pets, and farm animals.

“We have now discovered that ticks can be lifted across air gaps several times larger than themselves by the static electricity that other animals naturally build up. This makes it easier for them to find and attach onto animals that they want to latch onto and feed from. Until now, we had no idea that an animal could benefit from static electricity in this way, and it really opens up one’s imagination as to how many invisible forces like this could be helping animals and plants live their lives,” Sam concluded.

The scientists will now look at whether ticks can detect the incoming electrical charge of their potential hosts.