Even flies can be put off rotten food by its yucky smell. Scientists have discovered that fruit flies have special sensory cells to detect geosmin, a chemical produced by bacteria. This means they can avoid colonies of harmful microbes when feasting on yeast – their favourite food – on the surface of fermenting fruit. Flies don’t have noses but odour-sensing cells on their antennae and mouthparts (so they can’t join in the fund-raising stunts of today’s Red Nose Day in the UK). Fruit flies are used extensively for research into the role that genes play in the animal sense of smell, known as the olfactory system. Pictured is a fruit fly’s head with dots of colour marking different types of odour-sensing receptors, with superimposed letters denoting the gene sequences that keep them active.
Written by Mick Warwicker
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