You could be sitting alone and still be completely outnumbered for your body is home to trillions upon trillions of tiny passengers – bacteria. Your body is made up of around ten trillion cells, but you harbour a hundred trillion bacteria. For every gene in your genome, there are 100 bacterial ones. This is your ‘microbiome’ and it has a huge impact on your health, your ability to digest food and more. We, in turn, affect them. Everything from the food we eat to the way we’re born influences the species of bacteria that take up residence in our bodies.
Your skin is teeming with bacteria. There are billions of them, living on the dry parched landscapes of your forearms, and the wet, humid forests of your nose. On your feet alone, every square centimetre has around half a million bacteria. These microbes are more than just passengers, hitching a ride on your bodies. They also affect how you smell.
Skin bacteria are our own natural perfumers. They convert chemicals on our skin into those that can easily rise into the air, and different species produce different scents. Without these microbes, we wouldn’t be able to smell each other’s sweat at all. But we’re not the only ones who can sniff these bacterial chemicals. Mosquitoes can too. Niels Verhulst from Wageningen University and Research Centre has just found that the bacteria on our skin can affect our odds of being bitten by a malarial mosquito.
