There is a proposition online in the news media that the similar chemicals in catnip and silver vine, nepetalactol and nepetalactone respectively, can help protect a cat from mosquitoes and perhaps other parasites, as well as giving them a high. Do cats deliberately seek this protection from mosquitoes? The idea comes from a research study published on Science Advances. The news media appear to have got this wrong because it has been known that nepetalactone from catnip has a mosquito-repellent activity when it’s applied to people.
Because of this knowledge researchers wondered whether domestic cats would also benefit from the same protection. And perhaps, too, they deliberately use this anti-mosquito protection that these chemicals provide to their advantage. The point is that the known protection to humans prompted the question as to whether cats use the chemicals as a defense against mozzies.
Twin effect
It appears that nepetalactol has “twin effects” namely as a pest repellent and as an intoxicant. We know that cats rub their heads and bodies in catnip. They become intoxicated and are clearly in this state of intoxication and relaxation for a while.
Wild cat species also respond to these chemicals to varying degrees. The research found that nepetalactol was the most potent compound in silver vine leaves and when cats rubbed against the leaves nepetalactol was deposited on the body which repelled Aedes albopictus mosquitoes (and perhaps Aedes aegypti which is responsible for spreading dengue fever and other diseases). They found that significantly fewer mosquitoes landed on cats when they had rubbed in this chemical.
Discussion
The experts suggest that cats rub themselves with silver vine leaves and catnip in order to protect themselves from mosquitoes. The question I have and which is prompted by this research is whether domestic cats deliberately roll around in catnip or silver vine, when it’s available, as a deliberate method of providing a defence against mosquitoes. That to me is the discussion point. We know they enjoy the high they get from these chemicals but is there an added benefit which they know about? My personal viewpoint on this is that the mosquito-repellent benefit is probably unknown to cats. It just happens to be an added benefit.
I make this suggestion because I don’t think mosquitoes are a major hazard to domestic cats. I never seen anybody discuss mosquito bites as being a particular and concerning health issue for domestic cats. Not in the same way that they are the people, for example. There is no doubt that mosquitoes do bite domestic cats perhaps most likely on their ear flaps where there is little protection from their fur. But normally, in respect of the rest of their body, their fur must provide a lot of protection which mitigates the need to rub themselves with nepetalactol to ward off mosquitoes.
Where does catnip and silver vine grow
There is another issue. Catnip is native to Southern and Eastern Europe, the Middle East, parts of China and Central Asia. The domestic cat is a domesticated North African wildcat. Therefore the wildcat did not and does not encounter catnip in their day-to-day activities. Therefore there is no inherent learned behaviour by the North American wildcat to use catnip or silver vine as a protection against mosquitoes it seems to me. The same applies a silver vine which grows in the mountainous areas of China and Japan. Once again this is not a part of the world where you would find African wildcats! The point I’m making is that I don’t think domestic cats deliberately roll around in silver vine or catnip to protect against these parasites. They do it for the fun of it.
P.S. Silver vine is also called Matatabi. And cats also eat catnip. No protection in that activity.
The study: The characteristic response of domestic cats to plant iridoids allows them to gain chemical defense against mosquitoes by Reiko Uenoyama and colleagues.
