The butterfly with invisible wings
Glasswing butterfly (Greta oto)
Where you might see it
Not in Britain — the glasswing lives in the rainforests of Central and South America. You can sometimes spot one in a tropical butterfly house at a zoo or garden. Its wings are see-through, like tiny panes of glass with a dark frame.
Nature's problem
See-through wings should be the perfect way to hide. But ordinary clear surfaces, like glass or water, catch the light and flash with bright reflections — and a flash of glare would give the butterfly away to a hungry bird in an instant.
Nature's solution
Looked at under a microscope, the clear part of the wing is covered in millions of tiny bumps, far too small to see, all spaced very evenly. These bumps let the light pass straight through instead of bouncing back, so the wing hardly reflects at all. With no tell-tale glare, the butterfly stays truly hard to see.
What people made
Scientists studied those tiny bumps and copied them on purpose to make 'anti-reflective' surfaces — glass and screens that do not bounce light back at you. The same idea helps phone and tablet screens you can still read in bright sunshine, camera lenses that flare less, and solar panels that soak up more light instead of wasting it as glare. This one was deliberately copied from the butterfly's wing.
Try this
Tilt a phone or tablet screen under a bright light or near a window and watch it flash with reflections. That glare is exactly what the glasswing's wing avoids — and it is why a shiny screen is so hard to read in sunshine. Look for screens or glasses that are described as 'anti-glare' and see how much less they shine back.
Curriculum links
Light — how light reflects off surfaces
A surprising twist on reflection: most surfaces bounce light back, but the glasswing's wing is built to stop reflections, sharpening pupils' idea of what reflected light is.
Explore this on the site: Year 3: Light
Evolution and inheritance — adaptation and camouflage
Transparency as camouflage: see-through wings are an adaptation that helps the butterfly avoid being seen, a vivid example of a body suited to its surroundings.
Explore this on the site: Year 6: Evolution and inheritance