Scientists have uncovered the secret of the ladybug's folding wings

2024 Author: Seth Attwood | [email protected]. Last modified: 2023-12-16 15:55

Scientists from the University of Tokyo were able to uncover the secret of the folding hind wings of ladybirds, having found out that not only the already well-studied "hydraulic drive" with a mesh of vessels, but also the elytra with the abdomen, are directly involved in this process.

The researchers' work is published in the Proceedings of the National Academy of Sciences and is summarized at Phys.org.

Ladybugs are able, when walking on their feet, to fold their wings compactly under rigid elytra to protect them from damage. If it is necessary to take off, the rear webbed wings unfold in an average of 0.1 seconds. This mechanism is well understood, because ladybugs raise the elytra before spreading their wings.

The membranous hind wings of beetles under the elytra are folded like origami and are penetrated by a network of vessels filling with liquid. Before takeoff, the ladybug raises the elytra and strains the muscles of the third thoracic segment, increasing the fluid pressure in the vessels of the flying wings. As a result, the elasticity of the vessels increases and the wing expands.

Scientists have not been able to see in detail the process of folding the wing. The fact is that after landing, the ladybug folds the elytra and only after that begins to retract the hind wings, actively helping itself with the abdomen. On average, beetles take about two seconds to fold their flying wings.

To study the folding of the wings, scientists used a seven-spotted ladybird (Coccinella septempunctata). She had a part of her right rigid elytra removed. The deleted area was then used as a tool to create a copy of clear UV-curable acrylic resin. An acrylic copy of the elytra was then pasted onto the remainder of the ladybug elytra.

The researchers carried out a rapid survey of the beetle, and also studied a remote part of the elytra under a microscope. It turned out that the inner side of the elytron has a relief corresponding to the pattern of the vessels of the flying wing. In addition, on the inner side of the elytron there is a kind of "Velcro" - areas covered with the smallest bristles that hold the folded wing.

Similar "Velcro" are located on the upper side of the abdomen. It turned out that after landing, the ladybug folds the elytra, and then begins to tighten and straighten the abdomen. At this moment, the pressure in the vessels decreases. At the first tightening of the abdomen, the vessels fit into the corresponding recesses on the inner side of the elytron.

After relaxation of the abdomen, it slides along the underside of the hind wings. Then the ladybug again strains the abdomen, which, tightening up, picks up the wings and tuck them under the elytra. In this case, the transparent membranes between the vessels act as guides when folding the wing.

As scientists note, unlike origami itself, the wings of a ladybug do not fold at sharp angles, but rather curl. Due to this, their mechanical strength is likely to be preserved. In addition, twisting makes it possible to avoid kinking of the vessels and their overlap due to deformation.

So, by contracting and relaxing the abdomen, the ladybug achieves complete folding of the hind wings under the elytra. Researchers believe that the folded elastic wings begin to act as a kind of compressed springs. When the elytra are raised, their inner part ceases to cling to the hind wings and they, like a spring, begin to straighten out. The spreading process is then picked up by "hydraulics".

Japanese scientists believe that studying the mechanisms of unfolding and folding the wings of ladybirds and some other beetles will find the best technical solutions for creating folding mechanisms for various equipment, from solar panels and satellite antennas to the wings of deck aircraft.

Currently, there are no mechanisms for folding and unfolding the wing similar to those in beetles. The mechanisms used on deck aircraft are a set of hydraulic drives and locks. The wing of a carrier-based aircraft at some distance from its root has a hinge-loop fold.

Special pumps, pumping up pressure in the hydraulic system, force the drive of the mechanism to unfold or fold the wing. In extreme positions, the wing is fixed. A foldable wing is used on decked aircraft to save space so that they can be more compactly placed in hangars or deck parking.

In early February this year, researchers from NASA and Brigham Young University presented a foldable radiator design for cooling small artificial earth satellites. This radiator folds and unfolds like origami. The device will control the level of heat transfer by adjusting the depth of the folds: the higher it is, the more heat the device will absorb.