AS funny as it sounds, butterflies’ taste receptors are located at their feet, so they actually use their feet to taste. Their feet are similar to those of taste buds of the human tongue.
These receptors in butterflies are used to test presence of toxins or other detriments that could harm.
There are contact chemoreceptors on the butterfly’s tarsus or foot. These chemoreceptors help them to sense the presence of dissolved sugars like the flower nectar.
When taste sensors are activated, the butterfly will retract its straw like proboscis to consume the detected nectar.
By just landing on the surface, a butterfly can taste if something to eat is available.
– SCIENCE BRIDGE ACADEMY