Tuesday, 12 August 2014

Natural technology. 3. The flexible zinc-tipped drill of a wasp

This natural technology series has already looked at the high tech engineering of the bacterium and the virus.

Here is another  miracle of the natural world, this time being more remarkable for its mechanical engineering design than its organizational complexity.

From http://www.scienceupdate.com/2014/06/was

Certain types of female insects are required to be able to deposit their eggs in plants and they do this via an ovipositor, a tube at the end of their abdomen. Sometimes it is necessary to drill through very hard structures. 

 See the Journal of Experimental Biology of 28 May  2014:

In the case of the parasitic fig wasp the ovipositor has to penetrate the wall of an unripe fig in order that eggs can be placed in a conducive environment. This wall is very tough and yet the wasp has devised a solution in the form of a hollow tube which is

  • Thinner than a human hair

  • Highly flexible and very long in relation to the body of the wasp

  • Indented with teeth-like structures

  • Strong enough to resist repeated bending

  • Very hard at the tip

  • Spoon-shaped at the tip for pollination

The hardness is about the same as  acrylic dental cement and this is achieved by the incorporation of zinc atoms into the tip, similar in form and function to a drill bit. The tissue behind the bit is constructed to absorb  energy while allowing the ovipositor to be steered as it bores.  It can bend and flex without breaking, a combination of properties achieved by a three part anatomy. The three parts slide along each other’s lengths and are connected by rail guides using dovetail joints, an arrangement which allows the needle to pierce tissue and cut it.

One of the mechanical engineers studying this organ points out that its design could lead to  microscopic boring tools, needles, and probes, including ones that could be useful for minimally invasive surgeries. Man copying nature, a recurrent theme in modern engineering.

It is also apparent that when mechanical engineers look at nature they achieve insights that would not be revealed to the average biologist. They see nature in ways that may not be noticed by those indoctrinated with the dogma that design in nature is only an illusion, since all is purported to be driven purely by random mutations and selection pressure, a view that becomes increasingly untenable each day as new insights are made into how nature works.

John Sears