According to the website, Science ABC, the taste sensor also helps them predict if the plants are good enough to lay eggs on. By standing on a leaf, they can taste it to see if their caterpillars can eat it.
Most adult butterflies can’t bite or chew. They eat mainly liquids like nectar, sap, juices from fruits, and sometimes even fluids from carcasses. They have a long, tube-like tongue called a proboscis, which works like a straw to suck up liquid.
