The cat's favorite should be the mosquito's horror

Catnip scares mosquitoes and many other insects have long been known in several different home remedies. But so far, no one has been able to pinpoint how the plant's scent affects the mosquito. This knowledge could make it possible to use the effect of the cat coin more effectively and on a larger scale, to protect people in vulnerable areas against mosquitoes and mosquito-borne diseases.

Therefore, a group of Swedish and American researchers has now initiated a project where they will map in detail what happens in the mosquito when it comes near the cat coin.

- The interesting thing is that the cat coin repels mosquitoes already at a distance, unlike, for example, the synthetic agent DEET that has effect only when the mosquito has landed. So you don't really need to apply anything to the skin to be protected by the substances in cat coin, says Nadia Melo, a researcher at the biological department at Lund University who works with the project.

In preliminary studies, she has seen mosquitoes react and fly away already at 80 centimeters. Previous research has identified a cat coin substance called nepetalactone, which is the active substance that scares away mosquitoes. It is likely to be caught by the mosquito odor receptors. The challenge that Nadia Melo and her colleagues will now face is to figure out which receptor it is about.

To do so, she uses genetically modified mosquitoes, where different odor receptors have been eliminated so that they do not work.

- What I hope for is that any of these transgenic mosquitoes will not react at all to the cat coin. Then I know that it lacks precisely the receptor that scares the mosquitoes away and then we can move on with even more detailed studies, ”says Nadia Melo.

The plan is to study other insects that also respond to catnip, to see if the same receptor is involved in them as well.

- We were thinking of collaborating with a lab that examines bedbugs and investigating if we see the same effect there. And we want to test for malaria mosquitoes, says Nadia Melo.

The study is expected to last for four years - and the research requires both patience and some blood.

- When conducting behavioral studies to see how the mosquitoes react from a distance, you have to have a hand at the end of the wind tunnel where they fly. It is often my hand, because I am very attractive to mosquitoes, says Nadia Melo with a laugh.