Where do butterflies hide when it rains?

Many people have seen butterflies, especially when the flowers are in full bloom, and they can often be seen in the wild. But generally speaking, butterflies can hardly be seen when it rains. When it rains, butterfly shelter is very important. When it rains, butterflies will hide nearby, such as flowers and leaves, and their wings will cling to the back of leaves, which can effectively prevent rain and wind. In addition, some butterflies will hide in dense places, such as grass and wheat fields. Because of its dense leaves, it also has the function of keeping out the cold.

For human beings, the heavy rain on their faces is at most a little uncomfortable. But for such a light and delicate creature as butterfly, the falling rain is equivalent to bowling from the sky! So whenever the sky is overcast, butterflies will look for shelter from the rain in their habitats, but if they can't escape, they will get wet by the rain. In this regard, biological and environmental engineers and other researchers at Cornell University in new york analyzed the effects of high-speed water droplets on the feathers, leaves and wings of insects such as butterflies and moths. They found that the microstructure on the surface of these creatures can not only be waterproof, but also make the high-speed water droplets that hit it quickly break and disperse, thus playing a protective role in the rain. Because the butterfly's wings are composed of hundreds of tiny scales, similar to the scales on fish, it can keep out the rain when it rains, and it won't really get wet.

They observed that when water droplets collide with the surface of leaves or butterfly wings, they will land on tiny concave-convex textures, thus generating waves similar to shock waves in miniature water bodies. These waves interfere with each other, resulting in the formation of wrinkle patterns when droplets diffuse, and their entire thickness is different. Then, just as the water droplets are about to rebound, the wave effect makes the burr on the wing surface pierce the water film, thus breaking the water droplets into tiny pieces.

The nano-wax layer on these natural surfaces helps to prevent water. The researchers found that this, together with the water droplet breaking effect, reduced the contact time between the liquid and the wing surface by as much as 70%. This in turn reduces the transfer of heat and momentum. This is of great significance for insects that need to keep warm to fly to avoid predators.