The morpho butterfly is one of the most beautiful butterflies in the world, recognizable by its large blue wings. Fascinating in many ways, the morpho has interested researchers for decades and never seems to run out of secrets to surprise us. The examples of innovations inspired by the wings of this butterfly are very numerous, and make the morpho butterfly a champion of biomimicry !
The morpho butterfly, a jewel of ingenuity and innovation
There are more than 100,000 species of butterflies in the world. They are at the origin of multiple and impressive biomimetic applications, as we have shown with the particularly enlightening example of moths. The morpho butterfly (of which there are several dozen species) is also the source of many diverse examples of biomimicry, of which this article is limited to an overview. The morpho butterfly has a positive and magical meaning according to certain Amazonian legends, which seems to be confirmed by the diversity of scientific innovations it has inspired!
The morpho butterfly is native to the warm, humid forests of South and Central America, an ecoregion with abundant biodiversity. It is one of the largest butterflies in the world, with a wingspan of up to 20 cm! The most represented species is the blue morpho (Morpho menelaus), usually called “common morpho” or simply “morpho”. This butterfly with a thousand and one secrets contains many treasures of natural ingenuity, which inspire and amaze scientists. Its wings, for example, have five distinct functions on their own: to fly, to warm up, to seduce females, to evacuate water and to prevent bacteria and dust from attaching themselves to them! The biomimetic innovations inspired by the wings of the morpho are incredible, who knows how far its flight will take us?
When the morpho butterfly teaches us to fly
The morpho butterfly has a unique way of flying. To flap the wings, it is important to be able to control the flow of air generated with each beat in order to direct its flight. In the book The Awakening of the Morpho (only available in french), the physicist Serge Berthier explains that the morpho butterfly uses the circulation of lymph for this, the equivalent of blood in insects. When the lymph is sent in large quantities to the wings, they stiffen. The morpho butterfly then uses this phenomenon when it flaps its wings downwards in order to generate a pushing force. On the contrary, when its wings go up, the lymph withdraws and softens them, which allows the morpho butterfly not to be propelled downwards. This technique has been transposed to modern technologies, in particular on small drones with flapping wings imitating this principle to fly!
Butterfly morpho and solar panels
Keeping the right temperature
Before flying, you have to be able to take off! It is important for the morpho butterfly to be able to warm up its body in the early morning before soaring into the air. It does this by alternately contracting muscles in its wings, which will allow it to warm up to the right temperature. In warm-blooded beings, the influx of blood helps regulate temperature. However, the morpho butterfly being poikilothermic, or cold-blooded, it is crucial for him to find alternatives. And there again, he has more than one trick up his sleeve: he can adjust his scales in order to emit infrared waves and release heat when it's too hot, and on the contrary to inhibit their emission when it's cold. to preserve solar energy. The scales of the morpho butterfly's wing are composed of chitin, a molecule whose size is around one nanometer (billionth of a meter). It is responsible for the thermal regulation of the butterfly. After 40°C, butterflies cannot transpire. The chitin emits in the infrared above this temperature to cool the morpho butterfly, and absorbs it below to warm it. A real technological gem!
According to universities from Australia and Germany, this phenomenon is of interest to researchers for the design of more profitable photovoltaic solar panels, which avoid the all too common problem of overheating. Indeed, the efficiency of photovoltaic panels decreases when their temperature increases sharply, it is in our interest to keep them at a good temperature. Thanks to the morpho butterfly, we can learn how to create solar panels that are thermoregulated, by adapting this mechanism to the appropriate temperatures for the production of energy. This example of biomimetic innovation also offers us the possibility of designing screens that consume less energy, self-regulating fabrics for textiles, photodetectors or infrared sensors! And we are not at the end of our surprises...
The morpho butterfly, in the colors of innovation
Structural color and its applications
The reason why the morpho butterfly is so popular with researchers is probably its beautiful blue color. Most animals owe their color to molecules called pigments. For example, the Cuban butterfly Eurytides celadon sports wings tinted with a pigmented blue. The morpho butterfly owes its color to a completely different phenomenon, linked to the structure of its wings! We're talking about structural color.
This structural color is due to the periodicity of the ridges that hollow the wings of the morpho butterfly, as well as a stack of lamellae that overhangs them, as shown below :
This has the effect of interfering with light, and only reflecting blue. This color is much more robust than pigments, which tend to degrade quickly after individuals die. The study of structural colors is part of a field of physics called photonics, which is very popular and rich in examples of applications in biomimicry.
For example, in order to fight against counterfeiting, molds have been developed from the iridescences of the morpho butterfly. By reproducing the structure of the scales of its wings in negative on the inside of the mold and by controlling the dimension of the reliefs, a unique colored pattern is conferred on the molded product, which makes it possible to identify it. This inexpensive and very generalist technique is an effective example of biomimicry inspired by the morpho butterfly!
Another example is using this structure for detect gas. Indeed, the wings of the morpho butterfly shine a different color depending on the liquid or gas in which they are immersed due to the speed of propagation of light within it. This feature can be used in conjunction with a camera to detect the presence of gases and their concentration. Now let's go for a walk to discover even more surprises from this surprising Lepidoptera...
The morpho butterfly, the fakir of the river
The morpho butterfly wings superhydrophobia
One day when the physicist Serge Berthier was in the middle of the Amazon rainforest to study morpho butterflies, he found one on the surface of a river, its wings under the water. What was his surprise when he saw it swim away (yes, it can swim!) and then come out of the water with perfectly dry wings! And in fact, despite the high humidity and the abundant rains in these regions, the wings of the morpho butterfly are always dry.
This is due to a phenomenon called the fakir effect, in reference to their ability to balance on a studded board without sinking into it. Indeed, the drops of water which are on the wings of the morpho butterfly are as if placed on their surface, and do not cling to them at all, remaining almost spherical.
This is called superhydrophobicity: the water folds in on itself rather than interacting with the nanostructures of the wings whose surface is very weak, and glides over them without wetting them. This property is very common in the living world, and is exploited to create filtering membranes or coatings capable of limiting friction with a fluid in an industrial context. It can even be used to clean without getting tired...
The self-cleaning nature of the morpho's wings
Unlike flies, which clean their wings and eyes with their legs, the morpho butterfly's legs are too short to allow it to reach its large wings. Luckily for him, he doesn't need it! In fact, the scales that cover them fit together like tiles, which creates a movement of the water drops in one direction, towards the outside of the wings. However, remember, the drops do not adhere to the wings of the morpho butterfly! They slip, and take away the bacteria and dust that are there. Real Kärcher cleaning, and effortless! Biomimicry was quick to take inspiration from this ingenious mechanism to create self-cleaning surfaces, such as glazing reproducing the texturing of the wings of the morpho butterfly by 3D printing techniques, which are much more economical than conventional glass.
All these examples of biomimicry inspired by the fabulous properties of the morpho butterfly show that life and biodiversity are full of ingenuity to help us meet our needs. We looked at the butterfly's wings, but what about the rest of its body? There are still many fascinating properties to explore and transpose to innovate, starting with the hooks of its Velcro-like claws... So many promises and proofs of application that can only encourage us to protect biodiversity for the benefit of all !