Houseflies taste food with their feet using sensors that are 10 million times more sensitive to sugar than a human tongue.

The housefly, or Musca domestica, has sensory organs called tarsal chemoreceptors on the ends of its legs. These receptors connect directly to the fly's brain. When a fly lands, its feet send immediate signals about the chemicals on that surface.Research shows these receptors detect sugar at concentrations as low as 1 part in 10,000,000. Humans usually need a concentration of 1 part in 100 to taste sweetness. This high sensitivity helps flies find sugar quickly to fuel their fast metabolisms.When the feet touch sugar, they trigger a reflex called the Proboscis Extension Response. The fly automatically unfolds its tube-like mouth to start eating. This entire process happens in less than 100 milliseconds.Flies walk around on food to map out the best nutrients. Their feet also have sensors for water and bitter tastes. These sensors help the fly avoid eating poisonous substances. This anatomy makes the housefly a very efficient scavenger.