Blinding Insects To Smells May Be The Best Repellent

20 March 2005
Posted by Chris Smith.

Scientists have unearthed a genetic linch pin which enables insects to pick up smells. Without it they cannot detect airbourne odours, including their next meal, a finding which researchers hope will lead to the development of powerful new insect repellants capable of making humans and crops invisible to mosquitoes and pests. Leslie Vosshall and colleagues, from Rockefeller University, found that insects including disease-spreading mosquitoes, plant pests like the corn earworm moth (which damages corn, tomato and cotton), and fruit flies which home in on rotting fruit, all rely on the same gene - dubbed Or83b - to detect smells. When the researchers removed the gene from laboratory fruit flies, the insects essentially lost their sense of smell. To find out why the team looked more closely at the insects' antennae - their equivalent of a nose - and found that all of the receptors that enable nerve cells to pick up the presence of an odour were missing. But they came back when the scientists replaced the absent Or83b gene, even if it was the equivalent gene taken from an insect of a different species. The Or83b gene therefore seems to play a key role in ensuring that smell receptors find their way to the correct places on the nerve cells in insect antennae and might prove to be an Achilles heel which can be exploited for the development of novel insect repellents which work by blocking insects' senses of smell. According to Leslie Vosshall, "If we could use this to interrupt the transport of odourant receptors, we could make mosquitoes 'blind' to humans. That in turn would be a good way to prevent disease transmission". The researchers are therefore hoping that it will be possible to develop novel insect repellents which work by blocking the action of the gene.

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