Do you have any idea what is living on your face?

Although you may not recognise them, scientists say they are living on your face right now.

A new study found the mites, invisible to the naked eye, in 100% of the people they tested - and say they are transferred within families.

The new study, led by scientists at Bowdoin and the California Academy of Sciences, revealed the fascinating, little-known natural history of the face mite species Demodex folliculorum, using genetic testing to link the microscopic animal's evolution to our own ever-evolving human story.

By zooming in on a type of genetic material (called mitochondrial DNA) in mite samples from around the world, scientists discovered that different human populations have different mites, that those mites follow families through generations, and that they are not casually transferred between humans. 

The study is published today in the Early Edition of the journal PNAS.

'It's shocking that we're only just discovering how deeply our histories are shared with the mites on our bodies,' said Dr. Michelle Trautwein, Academy curator of entomology and senior author of the new findings.

'They aren't just bugs on our faces, they are storytellers. 

Mites tell us about our own ancient history--it's a complex story, and we've only just scratched the surface.'

Dubbed 'face mites,' D. folliculorum are actually tiny arachnids that inhabit hairs throughout the human body and consume skin cells and oils. 

Mites exist in human ears, eyebrows, and eyelashes as well as hairs that cover nipples and genitals.

For most people, mites are harmless. 

For some, however, mites can be associated with various skin and eye disorders including rosacea and blepharitis. Trautwein says this is one reason among many that scientists need to learn more about these constant human companions.

The study authors sampled 70 human hosts from around the world. 

For some subjects, intact mites were collected by drawing the curved end of a bobby pin across a participant's forehead; in others, metal laboratory spatulas were used to take samples that included a mix of hair and skin cells (including mites) from cheek and outer nose. 

The scientists then sequenced mite DNA to look at the mitochondrial DNA of each subject's mites.

'We discovered that people from different parts of the world host different mite lineages,' says Trautwein. 

'The continent where a person's ancestry originated tended to predict the types of mites on their faces. 

(Daily Mail)