Yes, the common housefly can taste food with its feet though it uses its mouth to eat. This is because its taste receptors that facilitate the sense of taste are located in its lower legs and feet. So when it lands on anything edible, it reflexively extends its proboscis or mouthpart to consume it. It is said that their feet are 10 million times more sensitive than our tongues.
The need for so many taste organs in insects is not understood very well. However, a clue for understanding their function comes from examining the anatomy of the taste-sensing neurons. These neurons send projections to different parts of the central nervous system of the fly. This suggests that taste information received from different parts of the body is processed differently in the brain. Therefore, different taste organs may have different functions.
To test this idea, Thoma et al. used the fruit fly Drosophila as a model for insects. With Drosophila, it is possible to target small numbers of neurons and to block them or activate them with genetic tools. The scientists blocked different groups of sweet-sensing neurons and measured sugar choice, the first step in feeding behavior. Normally, hungry flies choose sugar very quickly, but the flies which had all sweet-sensing neurons in their legs blocked could not choose sugar.
The scientists then examined the sweet taste neurons in the legs and found two populations of neurons. One group of neurons connected directly to the brain of the fly. The remaining neurons connected to the ventral nerve cord, a structure analogous to the spinal cord in humans.
Credit : ScienceDaily
Picture Credit : Google
