The tiger mosquito is a feared vector of viral diseases such as dengue, zika, yellow fever and chikungunya fever. The female animals sting and suck blood so that they can reproduce. The preferred victims are us humans. Mosquitoes find us by following CO2 from breath and body odors. These are a mix of hundreds of different scents, such as alcohols and ammonia. The mosquitoes recognize the substances with the help of sensory cells, so-called olfactory neurons, on their antennae.
But how exactly is the olfactory information processed? There is a kind of dogma among olfactory researchers that in animals each olfactory neuron carries only a single type of receptor. This receptor responds to very specific chemical compounds in the air. When the receptor is activated, the neuron sends a signal to the brain. The brains behind this principle – each neuron carries only one type of receptor – are Linda Buck and Richard Axel, who were awarded the Nobel Prize in 2004.
Based on these findings, researchers tried to switch off the mosquito receptors. The hope: certain neurons of such manipulated animals no longer transmit to the brain and human prey is no longer flown to. But the approach didn’t work, the mosquitoes found their target anyway. Why?
In the new study, the research team showed that the neurons of mosquitoes carry not just one but several receptors. “You could throw all the rules of Buck and Axel in the bin with the mosquitoes,” says co-author Leslie Vosshal, according to a statement from her institute. The researchers expected massive skepticism about their results, after all they contradicted the generally accepted dogma. They therefore confirmed their findings in a whole series of experiments. They also showed that the same neuron can be activated by two very different substances.
