We tend to view the wings of a butterfly as we do our fingernails or hair. We think of them as lifeless, rigid structures that serve as airfoils only useful for flying. Researchers at Columbia University led by Dr. Nanfang Yu have discovered that butterfly wings are more than inert tissue. The wings are equipped with living tissues that serve other critical factors for the butterflies. The design of butterfly wings is more than beautiful.
Using thermal imaging, the scientists measured the emissivity of the wings. That means the ability of the wings to emit thermal energy. Butterfly wings have veins that carry hemolymph (insect blood). Male butterflies also have scent patches that release pheromones for attracting mates. The researchers found that the emissivity of the veins and patches was very high. That means the wings of butterflies are engineered to emit thermal energy to prevent the insect from overheating in the hot sun.
The veins of the butterfly wings are covered with a thick layer of chitin, which is the material that makes up the insect’s exoskeleton. The patches on the wings have tube-shaped nanostructures and extra chitin. Thick and hollow materials are better at radiating heat than thin, solid materials. Butterflies are designed to handle high temperatures, and science is just beginning to understand how the design of butterfly wings works to cool the insects.
The study included more than 50 different butterfly species. The conclusion the scientists reached is that butterfly wings are “living structures” not inert material. The design of butterfly wings prevents the insect from overheating as well as allowing it to fly.
That butterfly in your garden is not only beautiful but a creature with a highly complex design. We are still learning about the fantastic transformation that takes place when a caterpillar changes into a butterfly. The study of the butterfly’s wings adds another layer of design and intelligence to what God has done with these incredible insects.
One of the most amazing things we see in the natural world is the ability of some living things to make incredible migrations. In the past, we have described the monarch butterfly’s migrations from wintering areas in Mexico to northern parts of the United States covering a round trip of about 10,000 kilometers. However, we see that painted lady butterflies out-migrate monarchs.
Scientists have studied how the monarchs navigate such incredible distances with formidable obstacles in their way. Biologists have proposed a variety of models as to how these fragile butterflies could acquire such an ability. However, in the case of the monarchs, the journey is not made by a single butterfly but by a succession of generations.
Science News for July 21, 2018 (page 4) told about a study of another butterfly with an amazing migration. It has the scientific name Vanessa cardui and is commonly known as the painted lady butterfly. These butterflies live in Southern Europe and migrate to Africa in the fall–a distance of 12,000 km. That’s 2000 kilometers farther than the monarchs, and the journey involves crossing the Sahara Desert. As with the monarchs, scientists had believed that the migration involved several generations. New techniques allowed researchers to put markers on the painted ladies when they were caterpillars. We now know that at least some of the butterflies make this incredible journey in one lifetime.
It is spring in the Northern Hemisphere, and one of the joys of spring is seeing the amazing migrations of birds as they move north from their wintering grounds. We watch the birds without thinking of the logistics that are involved in millions of birds moving over fast distances. How do you feed these hordes of living things? Their needs are even greater than usual because of the energy required for the long flights. We may not realize the importance of insect migrations that occur at the same time. What collateral benefits does this system create?
Dara Satterfield of the Smithsonian Institution in Washington, D.C. says, “Trillions of insects around the world migrate every year, and we’re just beginning to understand their connections to ecosystems and human life.” This migration not only feeds birds, but they pollinate wild plants and gobble agricultural pests.
We have written in our quarterly journal about the spring migration of monarch butterflies from Mexico to North America. In Europe and Africa, the migration is even more amazing and complex. Each spring the painted lady butterfly travels from Africa across the Sahara desert and the Mediterranean Sea into Europe and then retraces that journey in the fall. Because their life expectancy is so short, it takes six generations of butterflies to accomplish this migration. The butterflies avoid the extreme heat of North Africa in the summer, but they arrive in Africa just in time to feed from the flowers in the fall. Those butterflies are vital to the balance of living things in Europe.
Some of the insect migrations are very important to human food production. The marmalade hoverfly eats aphids during the larvae stage, and as adults they pollinate plants. The volume of insects is seen most clearly in the Pyrenees and Alps. Millions of hoverflies use the winds blowing through the mountain passes to get from one place to another. Scientists have been monitoring this migration because of its economic importance to agriculture in Africa and Europe. There is also a hoverfly migration in the western United States, but it has not been studied.
The size of these insect migrations is hard to comprehend, and we fail to understand the complexity of this system. Studies in the southern United Kingdom estimate that 3.5 trillion insects migrate over that area every year. Without those insect migrations, ecosystems on this planet could not exist.