What is the function of a butterfly

Butterfly dust

The scales are about 0.1 millimeters long and 0.05 millimeters wide. Thousands of them are arranged like roof tiles on the wafer-thin butterfly wings.

The single-colored scales are made of chitin and have a structured surface. They are connected to the wing skin by a tiny pin that is hooked into a sleeve. When touched, the scales detach from their holder and fall off.

They have important functions: On the one hand, the scales are responsible for the coloring of the often brightly colored and shimmering butterfly wings. This coloring is determined by the combination of pigment and structure colors.

Pigment colors are chemical compounds that ensure the different shades of color on the wings.

Structural colors, on the other hand, are based on the physical nature of the scales: their surface is never smooth, but has fine grooves. The light is refracted in these and the angle of incidence creates a certain color impression. The structure colors are responsible for the shimmering metallic sheen of the butterfly wings.

In addition to the coloring of the wings, the scales have another function: Since they are hollow and air-filled on the inside, they serve to provide lift when flying.

If these lift aids that stabilize the wings are missing, flight is made more difficult or even impossible for the small insect. The butterfly has to expend more energy in order to move on in the air at all - its strength diminishes faster, it makes finding food more difficult, it dies earlier.

Hence the tip from butterfly expert Heinz Schumacher from the Working Group of Rhenish-Westphalian Lepidopterists (butterfly researchers): "One should - if at all - only touch butterflies very carefully on the side of the body and not press them too hard." Because the grip on the wings not only leaves butterfly dust on the fingers - it also means hardship for the insects.