Learn Something: Moth Dust

Once upon a time I used to be scared of moths.
Okay, also once upon a time, I used to be scared of butterflies.
But also I was 5 and anything that could move independently was indubitably possessed by the devil. How else would they be capable of purposeful movement? Life's mysteries.

Anyway, now that I have grown old and wise in my ways, I have realized that butterflies and moths (and robots and cats)((well actually the robots have yet to gain my trust)) are actually not in the least bit dangerous. Or out to destroy my immortal soul and bring evil to the land.

You see, the part about moths that always terrified me was the strange dust that they would always leave on your fingers after you touched them. (Or after they ferociously attacked you with malicious forethought.)
What WAS it? Poison? Tiny poison? Was this the moth-version of anthrax, a tiny deadly defense mechanism hidden upon otherwise incredibly mediocre looking wings?
Was it small confetti from a giant moth celebration, and the moth was freaking out about me touching it because it had a MASSIVE hangover? (Little known fact, moths are proven to be amongst the world's hardest partiers.)
Once again, life's toughest questions.

So now that I have become grown and capable of rational thought (most of the time) I decided I'd find out what exactly this business was.

Thanks to the wonders of the internet, I have the answers I have been seeking.

Moths and butterflies both belong to the order Lepidoptera which actually means "scale wing." Turns out, moth and butterfly wings are both covered in tiny modified hairs that form little miniscule scales. Here's a cool picture that I found thanks to discover magazine. This is an image of the wing scales of a Urania ripheus (Sunset Moth) through Reflected-light microscopy.

Cool, eh? Gotta love them colors. According to Focus.com,

"The scales are pigmented but they also contribute to the pattern on the wings by diffracting light through a complex microscopic structure of ribs and holes. A 2005 study at Princeton University in the US found that the scales showed differences in their structure that depended on their location on the wing and were independent of colour."

Apparently these scales are thought to be used for a number of reasons. These include

• Thermoregulation

The scales could provide an extra layer of insulation to keep them warm when the sun goes down.

• Camouflage

Moths tend to fly around more at night, and so the colors of their wings could often help them to blend in with their environment. 

• Mate attraction

The right configuration of color and pattern may help a moth attract its true love.

In conclusion, moth dust is not tiny anthrax. It is scales! To show that I have made my peace with the tiny winged creatures, here is a cool picture of a little tiger moth I liberated from the confines of my garage the other day.

Tiger moth being glam on some rocks.