LESSONS FOR JR HIGH SCHOOL STUDENTS

THE DR. MATILDA A. EVANS’ CLASS

Butterflies: Chemists on Their Feet

Butterflies are very unique chemists. Why? Because butterflies have the unique ability to identify chemical compounds. However, instead of having a lab like humans, they carry their “labs” on their bodies—at the bottom of their feet.

This is useful because butterflies don’t chew food the way many animals do. Instead, they eat by sucking nutrients through a tube-like mouthpart called a proboscis. You can think of this organ as being like an elephant’s trunk—and, like a trunk, the proboscis can curl up and unroll when needed. So a butterfly mainly drinks its food rather than chewing it.

The science behind “tasting” with feet

The foot of a butterfly is commonly described as the tarsi (singular: tarsus). The tarsi have special sensory structures called chemoreceptors.

• Chemo means chemical
• Receptors are structures that help specific signals be detected and sent to the butterfly’s brain

You and I use our mouths and noses to taste and smell. But many insects, like the butterfly, can “taste” with different parts of their bodies.

Scientist Dr. Jayne Yack has explained that some butterflies can even sense their environment in surprising ways—such as seeing with the rear end and hearing with their wings. Additionally, butterflies seem to have a strong urge for salty minerals. So, the next time a butterfly lands on your arm for a fast-food treat, know that you may be helping a natural process in nature.