Researchers at the University of Bristol have found that ticks may be drawn across air gaps several times bigger than themselves by the naturally occurring static charge on their hosts. Due to the fact that ticks cannot jump, this is the only way they would be able to establish touch with hosts other than their tiny legs, which enhances their likelihood of finding hosts to parasitize.
The findings reported in Current Biology represent the first instance in which static electricity has been linked to one animal’s attachment to another.
Many dreadful infections, like Lyme disease, are carried by ticks and can lead to human and animal demise. Therefore, attempting to lessen ticks’ capacity to adhere to humans and the animals they depend on has significant societal and economic benefits.
According to lead author Sam England of Bristol’s School of Biological Sciences, many species, including humans, can build up rather considerable electrostatic charges.
The researcher said, “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.”
These charges are surprisingly high and can be equivalent to hundreds if not thousands of volts – more than you get out of your plug sockets at home! Importantly, static charges exert forces on other static charges, either attractive or repulsive, depending on whether they are positive or negative.
The researchers asked whether the static charges that mammals, birds, and reptiles naturally build-up may be so great that parasitic ticks could be attracted to these creatures electrostatically and lifted through the air, increasing their ability to find hosts to feed on.
The team’s initial experimentation involved introducing statically charged materials, such as rabbit hair, close to ticks to see if they would draw ticks to them. They saw how easily these charged surfaces could drag ticks over air gaps of several millimeters or centimeters, which is comparable to a person jumping up several flights of stairs.
The strength of the electric field created between an electrically charged animal and the grass that ticks like to sit in as they wait for hosts to pass by was then predicted mathematically using earlier measurements of the usual charge carried by animals.
He said, “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 determined 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 to their hosts by static electricity.
Many other parasitic species, like mites, fleas, or lice that wish to make contact with and adhere to their hosts, also experience this phenomenon, making it possible that it serves as a universal mechanism for animal contact and attachment. The finding makes it possible to create new technologies, including anti-static sprays, to reduce tick attacks in people, animals, and farm animals.
The ability of ticks to be drawn across air gaps several times their size by the static electricity that other animals naturally accumulate makes it simpler for ticks to locate and connect to the animals they want to latch onto and feed from.
The scientists will now look at whether ticks can detect the incoming electrical charge of their potential hosts.
Journal Reference:
- Katie Lihou, Sam J. England, et al. Static electricity passively attracts ticks onto hosts. Current Biology. DOI: 10.1016/j.cub.2023.06.021