Diamonds in the Sunlight: Iridescence in Insect Wings

We have discovered something wonderful quite by chance!

If we explore our insect wings under the microscope against a light background we get beautiful patterns of veins BUT if we explore them on a dark background a rainbow of colours are revealed!


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An insect's wing has 2 membranes full of tiny shapes and structures

which behave like tiny prisms in the sunlight.

Light hitting the top membrane is bent by the tiny structures, travels

to the bottom membrane and is bent again. All the bending splits

the light into beautiful colours. This bending is called refraction.



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Build a Model of an Insect's Wing

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Insect wings have different patterns of veins.

These are used by entomolgists (scientists who study insects) to

identify different insect species, each of which has a different

pattern of veins. These scientists also use the coloured patterns

of iridescence as an identification aid.


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The Cross-section of an insect's wing vein showing the

trachea which carries oxygen to the wing and the nerve which

helps the insect sense its wing position in flight.

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An insect's wing under a microscope against a light and dark
background.
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To the naked eye an insect's wing looks like a flimsy piece of

plastic. In fact it is quite a complex piece of technology. Its

main veins give longitudinal bracing to prevent the wing from

collapsing in 'pleats'. Its cross veins provide sideways bracing to

keep the veins apart, hold the membrane in shape and stop

tears from travelling down the wing. Its microstructures act like tiny

prisms which sparkle in the sunlight to help insects find each other.

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Use the book in the display and the key to the wing parts

to build and marvel at the structures in a wing.

Building the Wing



On the bottom membrane add the layer of microstructures.

Then assemble:

6 Veins in order from the leading edge of the wing:

  1. Vein 1:Costa (unbranched)

  2. Vein 2:Subcosta (unbranched)

  3. Vein 3: Radius (branched)

  4. Vein 4: Media (branched)

  5. Vein 5: Cubitus (branched

  6. Vein 6: Anal (unbranched)

Down each main vein poke:

  • a trachea (carries oxygen)

  • a nerve (registers what the wing is doing in flight)

Then add:

Cross veins (for sideways bracing)

Vein branches - use the branch joiners

Pterostigma ( the heavier dark spot used in flight manoeuvres)

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