Ant hair is about 98% reflective, and is very similar to how fiber optics work. SEM images in the link for fellow nerds.
On shaving ants:
Speaking to MailOnline, Willot confirmed this 'was indeed a tricky procedure. They are very reactive and won't stop struggling once caught, preventing any shaving attempt if not anaesthetised.'
This was done by exposing the ants for a few seconds to carbon dioxide, then strapping them down firmly.
Hairs were removed using a high-power binocular telescope and a very sharp blade.
'It's the same as shaving your own chin: the scalpel blade has to move in the opposite direction of the hair's growth. It has to be a delicate and gentle motion,' said Willot.
After practising on large soldier ants, he found that a smaller worker ant could be entirely shaved in an hour of delicate work.
He estimates around 40 ants were shaved altogether to produce seven good examples for the experiments.
"'It's the same as shaving your own chin: the scalpel blade has to move in the opposite direction of the hair's growth. It has to be a delicate and gentle motion,' said Willot."
You should not shave against the grain. It causes razor burn and in-grown hairs.
Can we get a study on how shaving ants against the grain fundamentally differs from humans doing it? (I mostly just want to see how much patience people have for shaving ants, though)