Insect Wings - Wonders of Creation

What aeroplane in flight could stop dead, hover, loop the loop and somersault in its own length, then land and stick to the ceiling of an aircraft hanger? Insects such as the humble housefly can perform any one of these acrobatic feats - and complete the movement within a second! Insect flight has only recently become the subject of serious scientific investigation, and it is already clear that each of these tiny creatures is a marvel of engineering design.

The basic structure of an insect wing may, at first glance, seem plain enough - a tough, thin membrane intersected by rigid supporting struts called veins. But  read on! A review of progress has been written in the November 1990 issue of Scientific American by Dr Robin Wootton of the University of Exeter. One wing region may have broad veins or cross-strutting for rigidity. Elsewhere, the membrane may be crumpled to  allow it to extend and deform. 

Even the molecular structure of the membrane itself may vary throughout the wing. Also, there are lines of flexion, shock absorbers, counterweights to stop the insect tipping, and ripstop mechanisms to minimise damage. The wing will even collapse on collision to prevent its breakage, then quickly respread again after impact. The insect flies by combined flap and twist effects. More sophisticated added mechanisms include changing the wing camber (the wing curvature that generates lift), varying the wing area by either overlapping or partly folding up the wing, reversing the camber by variation of body twist and wing stroke angle, and `clap and peel' motions which bring the wings together above and diverge the leading edges to generate yet more lift.

Dr. Wootton, after studying the wings of the slow-flying, hovering flies and dragonflies, exclaims that `their wings have proved to be small masterpieces of ingenious design'. He concludes by saying:

`The better we understand the functioning of insect wings, the more subtle and beautiful their designs appear. Earlier comparison with sails now seem quite inadequate.  The wings emerge as a family of flexible airfoils that are in a sense intermediate between structures and mechanisms, as these terms are understood by engineers. Structures are traditionally designed to deform as little as possible; mechanisms are designed to move  component parts in predictable ways. Insect wings combine both in one, using components with a wide range of elastic properties, elegantly assembled to allow appropriate  deformations in response to appropriate forces and to make the best possible use of the  air. They have few if any technological parallels - yet.'

Such exquisite design features may, by some, be attributed to the forces of natural selection acting on random mutations, but this is becoming increasingly unconvincing. We are thrilled to recognise the handiwork of our God. He is the master craftsman and we must honour Him as the Designer! Biologists are privileged to study objects which are powerful witnesses of the power and wisdom of God. How can we get these ideas over to the ordinary folk of our generation? How can the sophistications of this `hyper-technology' be communicated? We would be interested to hear from Biology teachers, or any others who have opportunity to test out different ways of getting the message out. What sort of exhibits could be used in a God-honouring museum? What poster displays might be prepared for the BCS exhibition stand? What about projects suitable for use in schools? Your ideas are invited!

David J. Tyler (1991)

Karner Blue Butterfly image credit: US Fish & Wildlife Service/John & Karen Hollingsworth

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