Mosquitoes can be taught to steer clear of particular people — even those who smell particularly alluring.
Jeffrey Riffell at the University of Washington in Seattle and his colleagues wafted appealing human odours towards yellow-fever mosquitoes, Aedes aegytpi, while also giving the insects swat-like mechanical shocks. The mosquitoes learned to suppress their urge to fly towards the scent — a lesson they were unable to learn after the team disrupted their receptors for dopamine, a compound that carries messages between neurons.
The scientists monitored the mosquitoes’ brain cells as the insects learned to suppress their responses to some of the individual compounds in attractive body odours. Different classes of chemicals tended to trigger the firing of neurons in a slightly different patch of the brain, giving the researchers a map of the brain areas involved in coordinating the mosquito’s response to odours.