What body part does a butterfly use for tasting?

A butterfly uses its hind feet to taste the surfaces on which it lands.

The feet contain specialized chemical-sensing structures that detect substances on leaves, flowers, mud, and other surfaces. This process is often called contact chemoreception. It lets a butterfly sample a plant without having to eat it first.

The ability is especially important for females, which must select suitable host plants for laying eggs. Many caterpillar species can eat only a narrow range of plants, so a female butterfly’s feet help determine whether a leaf is appropriate food for her future offspring. Butterflies may also use their feet to detect sugars, salts, and minerals.

A common mix-up is saying that butterflies taste only with their mouths. They do have taste receptors in other locations, including the mouthparts and antennae, but their feet are the famous and unusually important tasting organs. Some butterflies even land on mud, tears, carrion, or sweaty skin to obtain salt and other nutrients.