A nerve signal can cause up to 40 contractions in the asynchronous wing muscles. One muscle group pulls the insect body together (C), causing the wings to lower. Another group compresses the body lengthwise with each contraction (D), causing the wings to rise. A = wings, B = wing joints.
A young dragonfly has freed itself from its doll. The jungle around is quiet and is not disturbed by humming insects, but that changes as soon as the wings of the slender animal have dried up in the sun. The prehistoric giant insect rises from the ground and makes the first flight of world history.
Since flying insects took off about 325 million years ago, the development of wings has always proved to be a route to success in the animal kingdom: bats - the only mammals that can fly - today make up around one fifth of all mammalian species. Birds are the only group of dinosaurs that managed to survive the gigantic death of these primordial animals. And the third group of animals with wings - insects - is by far the most species-rich on earth.
Flying animals not only perform well because they can quickly escape predators, but also because flying has yielded their other beneficial properties. Thanks to their wings, birds perceive the world twice as fast as humans, while bats can draw detailed 3D maps in their brains using sound.A special flight technique gives the smallest insects up to 25 percent more lift than larger animals.
Unique flight technology saves energy
Thanks to a special wing beat, the smallest insects can be up to 25 percent more energy efficient than larger ones.
Wings open like a book
The wings open from the back like the pages of a book. The fronts stay together, while the wings go along the body.
Underpressure creates lift
A vacuum is created above the wings, which draws in air from below. This creates a lift of one and a half times the weight of the animal.
Back to the starting point
The wide spread wings cancel out the pressure difference. With a sweeping movement they go back to the starting point.
Number of species exploded
The first flying dragonfly was much larger than its current descendants. ?
Researchers have found fossils of prehistoric dragonflies with a wingspan of up to 70 centimeters. The then species fell under the meganeura, an insect genus that had a flowering time 380 million years ago.
The atmosphere then contained 35 percent oxygen, compared to 21 percent now, allowing the dragonflies to develop into large predators that lived off smaller insects. But only when they were the first to develop animal wings was the foundation laid for the great success of their offspring.
The first prints of wings were found in fossils of giant dragonflies that lived some 325 million years ago. In addition to this innovation in the animal kingdom, it can be seen from the fossils that the species wealth exploded among the insects - indicating that wings gave them a major advantage.
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Insects are very versatile pilots. They can float, fly backwards and accelerate enormously, but researchers have only recently started to study how they do that. In particular, the flight technique of the smallest species appears to be very complicated. A small body is not necessarily an advantage if you have to keep it in the air, because the wings are therefore minimal.
Small animals must therefore blow so quickly that the impulses of the nervous system do not keep up, while larger flying insects such as butterflies and bumblebees can with one nerve impulse per wing stroke. Their nerve signals and their activation of the muscles are therefore optimally coordinated. The control of the wings is much more complex for the smaller insects. Nerve signals reach 360 km / h at most, and that is too slow for animals that have their wing muscles contract and relax more than 1000 times per second.
That is why the smallest insects have developed a technique in which a group of muscles contract and stretch many times per nerve signal. Each pulse triggers a kind of ultrafast muscle vibration that changes the shape of the animal's skeleton, causing the wings to move. For example, one surge in the nervous system can produce 40 wing strokes. Because the wings are out of step with the nervous system, we call this method asynchronous flying.
1000 times per second, the knot of forcipomyia (a kind of mosquito) hits its wings.
In addition to faster wing strokes, the asynchronous muscles offer even more benefits. In relation to other muscle types, the muscle fibers are arranged very symmetrically, which may help to increase the striking power of the wings.
In addition, zoologists have discovered that asynchronous pilots can fly much better backwards and float better, and that they can use the pressure changes in the air well to increase their upward force. Throughout history, bees, flies, beetles and bugs have independently developed asynchronous flight muscles..
Insects change shape to fly
Small insects have to hit their wings more than 1000 times per second to stay in the air. This is possible because different muscle groups contract the entire body ultra-fast.
- a (blue) = wings
- b (pink) = wing joints
- c (beige) = vertical muscles, which pull the insect's back in the direction of its abdomen, causing the wings to rise.
- d (orange) = longitudinal muscles, which contract the body of the insect lengthwise, causing the wings to go down.
A nerve signal can cause up to 40 contractions in the asynchronous wing muscles. One muscle group pulls the insect body together (C), causing the wings to lower. Another group compresses the body lengthwise with each contraction (D), causing the wings to rise. A = wings, B = wing joints.© Siga / WikiCommons
Scan sees dinosaur as a bird
Insects are not the only animals that have made an evolutionary journey from the land to the sky.
About 150 million years ago the archeopteryx, or 'the first bird on earth', was born. The researchers have long wondered whether this description is scientifically correct. Many experts point out that fossils clearly show that the animal had wings with feathers, but the archeopteryx also had teeth and a long, bony tail, which are characteristics of land dinosaurs.
Critics of bird theory therefore state that the animal could not fly and was no more than a stage of development in the transition from the dinosaur to the bird.
The archeopteryx is considered to be the first bird on earth, but for a long time it was not clear whether it could actually fly. New studies of fossil brains, however, show that the animal could certainly move through the air, even though it did not cover large distances.© Jane Burton / Getty Images
Researchers from the University of Ohio have now re-examined the matter by looking at the skull size of the animal. Because flying requires a lot from motor skills, the hypothesis was that if the animal could fly, its brain is larger than that of other dinosaurs.
The scientists examined a skull of an archeopteryx of 147 million years old, and based on 1300 X-rays, they made a 3D reconstruction of the animal's brain on the computer.
The computer model showed that the brain was 1.6 milliliters in size - about three times the size of the brains of equally large reptiles.
The ear canal was wide and the visual center in the brain also large, like that of current birds. Thanks to the evidence of the well-developed brain, scientists now agree that the archeopteryx could fly, even though it was not an air acrobat again.
Muscle mass turns hummingbird into acrobat
This bird has tuned every part of its body to a flying life. The hummingbird is the only bird that can fly backwards and stand still in the air.Shutterstock
Just like with other small birds, the image is refreshed extremely quickly. The hummingbird therefore notices movements twice as fast as people.Shutterstock
A brain center gives the bird its unique ability to flee either way, because it is particularly vulnerable when it floats through the air.Shutterstock
The shoulder is flexible and the wing can make horizontal eight. Unlike other birds, the wing strokes constantly create upward force.Shutterstock
The arm pins adjust the shape and size of the wing surface. This allows the bird to accurately determine its own lifting power.Shutterstock
The chest muscles are larger than with many other birds. Where muscles normally make up 15 percent of body weight, in hummingbirds it is 30 percent.Shutterstock
The legs are so small that the bird in the air is not slowed down by their weight. This means that the hummingbird cannot walk properly.Shutterstock
Birds see the world in slow motion
To fly, animals need very sharp senses - and birds therefore have the best eyes in the animal kingdom. Birds of prey must be able to see far.
That is why their eyes are close together, so that the visual impressions of the two eyes overlap. The so-called binocular vision, which humans also have, and the unusually high density of the retina receptors, give the animals such a sharp image that eagles, for example, can detect a prey the size of a rabbit at a distance of more than 3 kilometers .
Recently researchers from the University of Uppsala in Sweden demonstrated that prey birds also have an impressive view. In a test with captive wild birds of species such as the blue tit, the withals and the pied flycatcher, the animals were rewarded for reacting to the flash of a lamp. By increasing the flash frequency, the researchers tested how fast the birds processed the visual impressions, until the flashes came too fast to distinguish them from each other.
A hummingbird reaches 385 times its length per second: 8 times as fast as an F-15 fighter jet.
The spotted flycatcher noticed flashes of just 7 milliseconds. For comparison: the human brain can at its best capture visual impressions of 16 milliseconds. If we had the sight of these birds, it would seem like everything is moving in slow motion. The highly developed discernment is essential for catching the flying insects of which the birds live in the air.
Mammal also takes off
As the last animal group, mammals learned to fly 50 million years ago, at least a single species, when the first bats chose the sky. The flying mammal has emerged as a night fighter, who thanks to a very sophisticated brain can orientate solely on sound.The bat is the only flying animal that can adjust the stiffness of its wings.
Skin wings give bat a more powerful wing beat
Unlike with birds and insects, the wings of bats are not stiff. The plastic membranes of skin are full of muscles, which give the animal an extra powerful wing beat.
Wing smooth due to elastic fibers
Elastic fibers wrinkle the skin when the wing is relaxed. Due to the air resistance of the wing stroke, the wing becomes smooth and gives it a much more aerodynamic surface.
Fingers come together in the wrist
The wrists form the junction of a large part of the wing. Long finger bones run from here, with skin tensed between them.
Muscles make the wing hard
Thin muscle fibers run straight on the elastic fibers, which become active when the wing falls down. The wing makes the wing harder, which gives the stroke more effect.
At Johns Hopkins University in the US, a team of brain scientists have set up a space to investigate the flying arts of bats in the air. They can observe the animals with cameras and microphones on the walls. At the same time, small implanted sensors follow the brain activity while the bats fly through an obstacle course.
Possibly bats make a so-called static map of the environment, which they store in their memory. Nerve cells place an imaginary grid over the map, and the animal flies over such a grid line, then nerve cells are activated and the bat knows where it is on the map. Still other nerve cells transmit signals when the animal's head is at a certain angle to the environment and inform it of the distance to its chosen target.
160 km / h is the horizontal top speed of the fastest animal ever, the hare lip bat.
The bat also forms a dynamic map in the brain that, in contrast to the static one, always keeps it in the middle, as we also know from GPS navigation systems. The information for the dynamic map comes from the echolocation system of the bat. He emits ultrasound impulses that bounce off objects in the environment.
The echoes of these signals provide the brain of the bat with information about distances and directions, allowing him to draw a detailed map of the objects in the environment in the brain.
Scientists discovered, for example, that bats sometimes emit extra ultrasound signals, and their hypothesis is that the intensive sequence of signals gives the animal the opportunity to "focus" on objects that are interesting, which can be useful, for example, when the animal is navigating in a dense forest.
The first bat, Onychonycteris finneryi, was 12 cm long and had claws on all five toes - unlike the current bat, which has only 1 or 2 claws per leg. He could fly, but he orientated himself without echolocation, and scientists therefore think he was active during the day.© Nobu Tamura
Bats have the same sharp senses as birds, but because they are not dependent on visual impressions, they can hunt at night when few predators are active. The ability to map and store large areas in the brain allows the animals to fly whole ends to find areas with lots of food, which has been crucial to the success of the flying mammal.
Dronebouwers learn from animals
The navigation systems of bats can also benefit people. The American brain researcher and bat expert Seth Horowitz is working on a sensor device that mimics the echolocation system of bats. This allows blind and visually impaired people to send signals and absorb echoes of the environment. The device emits ultrasonic waves in all kinds of frequencies and can distinguish different types of objects.
For example, the echoes of one frequency range can provide information about obstacles, while another area warns of small objects moving fast. The challenge is to translate the sounds in such a way that the blind and visually impaired get a clear picture of the environment.
Birds also provide scientists with inspiration. Brain scientist Niels Rattenborg of the Max Planck Institute for Ornithology recently demonstrated that birds sleep - and can even reach the important brake sleep phase - while they fly. The birds do this by sleeping with one half of the brain at a time. Because sleep deprivation is a growing problem among people, Niels Rattenborg hopes to be able to learn from the birds how people can cope better with their sleep deprivation in the future.
Many birds can sleep with one half of the brain at the same time. You see that because they always keep one eye open.© Shutterstock
Finally, researchers at Wageningen University & Research have been inspired by the unique, stable flight of insects to build the invulnerable drone of the future.
Research of fruit flies shows that they can continue to fly despite severe wing injury, for example by striking their wings faster. So now the scientists have made a drone that stays in the air with one working wing. In this way another feature of flying animals has been exploited.