Tel Aviv University.
(photo credit: WIKIMEDIA)
Tel Aviv University zoologists have discovered the takeoff mechanism of tiny insects called tobacco moth aphids, a finding that can help aviation engineers to develop much more effective drones.
The research was just presented at a conference at Kibbutz Kfar Blum, in the Hula Valley, on the connection between mechanics and the physiology of flying creatures and published in the Journal of Experimental Biology.
The species, named Manduca sexta, is kept as a pet in some countries but regarded as an agricultural pest in others, as its larvae feed on leaves of various plants. It is commonly used as a model organism, especially in neurobiology, due to its easily accessible nervous system and short life cycle.
After it takes to the air extremely rapidly, the tiny inspect stabilizes with folded wings, using counterpressure from the wind on their edges.
“In recent years around the world, there has been an increase in cooperation between biologists and engineers to learn from the wisdom of nature and develop tools to serve humanity based on millions of years of evolution, said Dr. Gal Ribak, an expert in comparative biomechanics and ecophysiology of locomotion at TAU’s George S. Wise Faculty of Life Sciences.
Working with student Eyal Dafni in the lab, Ribak said they are focusing on the biomechanics of species and their aerodynamics.
“It is possible to plan more successful flying objects by learning from the tobacco moth aphid, which has a unique mechanism for taking off even before it spreads its wings,” he said.
The team photographed the bug using a video camera that records 3,000 pictures per second. Then they observed the pictures 50 times slower than the actual flight process, which took only 12 thousandths of a second.
“We saw that, unlike many winged insects, this aphid has a ‘biological spring’ that launches the bug upward with tremendous force and speed – 34 times the speed of gravitational acceleration,” Ribak said. “The launch makes the aphid unstable, and its body starts to roll over in the air. But it almost immediately manages to stop this movement even when its wings are folded and held closely to its body.”
To discover its aerodynamic secret, the researchers build a computerized model of the aphid’s body. This model showed that the insect is assisted by the air’s resistance so it can stabilize itself. The part of its body responsible for this is the tip of the wing.
“We discovered that when the wings are folded at the side, half of their surface area protrudes beyond the body along the whole length, and this creates resistance that brings the rolling to a halt,” Ribak said. “This is an automatic, built-in mechanism that the insect does not have to start on its own.”
Tobacco moth aphids whose wing tips were cut fail to stabilize in the air, he added.
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