Many species of insects have taste receptors on their feet. While the proboscis is usually tucked under the head, a fly’s feet extend out from the body to savor food. The fly’s feet are also used to groom itself before eating. This allows the fly to clean the taste sensors on its feet before eating.
Scientists have found that a fly’s feet have sensory receptors that allow it to detect different types of sugar. In addition to sugars, flies can also taste bitter compounds. They can taste trehalose, caffeine, and a super-bitter compound called denatonium.
The flies’ feet are equipped with taste receptors similar to those of humans. They have the ability to taste sweet, sour, bitter, and good. They can even taste odors. While the brains of mammals only map taste receptors on the tongue, flies have receptors all over their bodies, including on the legs, wings, and egg-laying ovipositor.
Houseflies can also taste with their feet. The receptors on their feet are 10 million times more sensitive to sugar than our tongues. There are over 120,000 species of flies worldwide, with 18,000 found in North America. Female houseflies can lay as many as 600 eggs during their short lives. Most flies live for about 21 days and undergo a variety of shapes during this time.
In order to better understand the process of taste perception, scientists need to understand the neural pathways in flies. They need to know which parts of the brain transmit signals to the feet, and which are responsible for which functions. This research is funded by a National Institutes of Health grant.