Changes in wing shape help small hoverflies stay aloft

An analysis of the Hoverfly flight shows that the design of the wings, and not faster, allows the smallest species to generate enough facelift to fly.

The study, published today in Elifeis described by publishers as an important work. They say that the authors provide convincing evidence that there is no significant link between the size of the body and the kinematics of the wings – the movements of the wings during their beat. Instead, the changes in the form and size (or morphology) of the wing allow smaller perfores to stay in the air. These results help to explain why the wings of insects have evolved to be so diverse in shape.

The physics of the flight becomes more difficult the smallest animals. For hoverflies, hovering to maintain their position in the air while feeding on nectar or the screening of potential partners is a crucial behavior that requires precise flight control. Large species of loss can generate liftions with relatively short wings, but smaller species are faced with a more difficult challenge because their facelift production potential with their wing beats decreases compared to their body weight as their size is narrowed.

“The steering wheel is essential for hoverflies because they nourish and keep a mating territory, but for the smallest insects, their wings are not evolving enough to follow the rhythm of their body weight,” said the main author, Camille Le Roy, postdoctoral researcher in the experimental group of Zoology, University of Wagengen, in the Dutch.

“Many scientists have hypothesized that small insects overcome this by modifying their kinematics of the wing beats. We wanted to test if small hoverflies really beat their wings in a different way to their larger counterparts, or if subtle changes in their wing form allow them to hover.”

The Roy and his colleagues examined the scaling relationships between the morphology of the wings and the body mass in 28 species of Woverfly ranging from 3 to 132 milligrams (MG). They jointly evaluated how the morphology of the wings and the kinematic scale of the word wing with body mass for eight species ranging from 5 to 100 mg.

They measured the duration of the wing, the wing area, the average rope (the average width of a wing) and the second moment of zone (s₂) – A measure of how the surface of the wings is distributed over its length, which can affect the amount of lift generated. They also used geometric morphometry, a statistical method which captures independent size differences in the waist.

For the eight smaller species of Hoverfly, the researchers filmed overflight sequences using three high -speed cameras synchronized. This stereoscopic configuration allowed them to reconstruct the movements of the wings and the 3D body and to remove the key measurements of the wing beats, including the frequency of the beats and the angles of the wings.

In all species, the team found that the kinematics of wing beats did not change significantly with body size: smaller Soverflies did not beat their wings faster or with larger stroke amplitudes. Instead, their wing morphology moved systematically with size: smaller species had proportionally longer wings and a higher S₂ The values, which means that more of their wing area has been positioned further from the hinge, giving them a greater lever effect.

Despite the diversity of the form of the wings, the vertical force scheme has been preserved between species. Each half-time has produced a small lifting peak followed by a larger one, the backstroke generally stronger. This emphasizes that, although the morphology of the wings goes on the quantity of lifting generated, the pattern of underlying wing beats remains the same.

The researchers then used IT simulations combining the shape of the wing of each species with a pattern of ways to test the quantity of aerodynamic lifting that their wing morphology could generate. These fluid simulations reproduced the differences in lift already observed between species, showing that most of the variation in weight support comes from the shape of their wing rather than the movement of beat.

The authors note that a limitation of this work is the missing aspect of the interaction between the movement of the beat of the wings and the muscle function (or physiology).

“Our analysis focuses on the wing -based propulsion system in Hoverflies, but their wing movement is finally propelled by the muscle engine,” said the main author Florian Muijres, professor of experimental zoology in the experimental zoology group of the University of Wageningen. “Future studies that integrate muscle physiology into aerodynamic modeling are therefore necessary to complete our approach.

“For the moment, our results show that small Soverflies do not solve flight physics by beating their wings differently from the largest – they solve it by being built differently. By stretching their scope and moving more surface from the hinge, the smallest species generate the additional elevator they need without having to change their specialized wings.”