Imagine that somewhere in your vicinity right now there is a mosquito looking for its next meal of blood. Run for it? Oh no my friend, because unfortunately for you the cheeky little fellow will have already picked up the scent of the carbon dioxide (CO2) in your breath. Mosquitoes are capable of detecting CO2 trails and following them to their hosts over long distances you see. But recently we may have found a way to fell a metaphorical tree over the mosquitoes’ gasseous tracks.
Frankly, it would be ideal if mosquitoes didn’t keep biting people. Mosquitoes carry the parasites and viruses that causes diseases like Malaria and Dengue fever and the WHO estimate that for every 5 children that die in Africa, 1 of their deaths can be attributed to Malaria. As I’ve written before, there are lots of different strategies scientists use to try to fight pests like mosquitoes, but one effective method is to use hormones or strong smells to confuse them. This has the benefit of not actually killing the insects, so unlike situations where pesticides are used, the species isn’t able to build up resistance by the process of natural selection.
It is possible to use decoy CO2 chambers as traps for mosquitoes (positioned near a house for example, to lure the mosquitoes away from it). This sounds like a great idea, but the practicalities prove tricky. Providing a source of CO2 in the kind of places where mosquitoes are a problem – developing countries for the most part, that is – is not usually easy. CO2 canisters or handfuls of dry ice are in understandably short supply in these locales.
I was intrigued recently then, when I discovered some new research  conducted by scientists from the University of California which showed that simple, inexpensive  organic molecules can also trigger the mosquitoes CO2 smell receptors. In fact when the researchers measured the mosquitoes brain activity when they smelled the organic compounds, identical parts of their brains lit up as did when they smelled CO2. But when they tested 2,3-butadione (below) something strange happened. The mosquitoes’ neurones started to fire like crazy and didn’t stop. In fact, a 1 second pulse of butadione induced a firing of the neurones for 5.5 minutes . With the CO2 signaling neurone gone haywire, it seems likely that the mosquito would no longer be able to sense delicious CO2 trails.