Tick Tricks

Ticks become more of a compelling topic each year, as they move silently, inexorably, into new geographical zones where they are not welcome. Of course, it’s not at all surprising that ticks are regarded as the enemy wherever they show their nasty little faces. In disease-spreading capability, they rival the great mosquito (most dangerous killer on the planet)—only more crafty and more cowardly, since mosquitoes at least give fair warning when they are biting you. The number of diseases they carry, like the territory they occupy, is gradually expanding; it’s enough to give you a real case of the creeps.

Want to know whose feathers aren’t getting ruffled by the fact that these disease-ridden pests seem to be taking over? The birds and other wildlife that live among us. Even though they don’t have access to the safe and highly effective medicines we apply to our pets, they can still protect themselves with some very nifty tricks.

One example comes from American black and brown bears. Pondering their habit of rubbing enthusiastically against tree trunks, researchers wondered if this might actually function to trap external parasites (like ticks) in the sticky sap that’s transferred into their shaggy coats. When exposed to the mere scent of tree sap, hungry ticks were repelled, so it’s now believed that bears + bark = bug repellent. Pretty cool, huh? Some types of monkeys have been known to lather themselves up in onion, pepper, or citrus scents for a similar effect on their own parasite issues. Certain compounds found in catnip also have a weak repellent effect on ticks; perhaps that’s at the core of the odd relationship between felines and this particular plant. Wild animal behavior gets even wilder, though. Certain primates and many species of birds will deliberately disrupt anthills to provoke the inhabitants. Their intention is to then rub and crush the angry ants into their fur or feathers, transferring formic acid from the ants’ bodies to their own. This compound then helps to ward off external parasites. Evolution is pretty amazing.

It doesn’t stop in the back yard, though. A 2016 study of domestic dogs revealed that certain breeds (beagles, for example) are inherently less attractive fodder for ticks. Further work with beagles showed that their skin produces two compounds (pheromones, essentially, but meant for communication with a different species as opposed to one’s own) that drive away these parasites. Those chemicals were then isolated on a small scale and made into a collar, which demonstrated that the very tasty cocker spaniel could be made less palatable for ticks by dousing himself in Parfum de Beagle.

Does this mean that ticks and their attendant infections can now be controlled via natural means, and that beagles are poised to take over the world? I’m afraid not. The work described above explored impacts on just one species, the brown dog tick. Furthermore, parasite load on study subjects was suppressed, but not eradicated; disease transmission can therefore still occur. However, it does provide an avenue for ongoing research into environmentally friendly ways of keeping people and pets safe.

Dr M.S. Regan