THE TINY MITES THAT HAVE SEX ON YOUR FACE ARE CLOSE TO EXTINCTION
The 0.3mm critters are just about visible to the human eye, and they’re crawling all over your body as you sleep
Microscopic mites that live inside the pores of your skin are using the oils you produce to fuel their ‘all-night’ mating sessions – and that’s actually a good thing. Once blamed for conditions like acne, rosacea and itchy scalps, these late-night lovers might actually be keeping our pores unblocked and free of the oils that contribute to skin problems. In fact, as the tiny mites do us more good than harm, they could be considered as much a part of our daily lives as the bacteria living in our gut.
Now, though, research from Bangor University and the University of Reading suggests that the tiny Demodex folliculorum mites might be under threat.
This first-ever study of the mites’ DNA has revealed that their ancient relationship with humans has contributed to the loss of much of the organisms’ genetic variety. Living in the follicles, particularly around the face and nipples, has left them so isolated that they’re approaching an ‘evolutionary dead-end’.
The mites are passed on from mother to baby during childbirth and early life, and do not appear to transfer between adult humans with close contact.
This means there are few opportunities for mite-mingling events, so mating pairs have passed on the same genes for millions of years, and shed the ones that were unnecessary.
“We found these mites have a different arrangement of body part genes to other similar species due to them adapting to a sheltered life inside pores.
These changes to their DNA have resulted in some unusual body features and behaviours,” said the University of Reading’s Dr Alejandra Perotti, who co-led the research.
For example, this gene reduction is part of the reason for their nocturnal behaviour. At some point, the mites lost the gene to produce melatonin, which is the chemical that nocturnal animals use to keep themselves awake at night. Luckily for the mites, melatonin is produced by glands on our skin at night, which they use to fuel their mating sessions.
Despite the fact the Demodex mites have had a relationship with us for millions of years, they are effectively on the path to extinction. Over the generations, the differences in the mites’ DNA have become smaller and smaller. Someday, the gene pool will be so small, they may become extinct.
The genetic analysis also dispelled one long-standing idea about the mites: that they don’t have anuses and hold onto all their faeces throughout their lifetime (a short two or three weeks) until they die. This dermo-dumping, researchers once supposed, could cause skin inflammation and problems like acne. But the Demodex mites don’t deserve such a bad reputation.
“These changes to their DNA have resulted in some unusual body features and behaviours”
“Mites have been blamed for a lot of things,” said Bangor University’s Dr Henk Braig, co-lead author of the new study. “[But their] long association with humans might suggest that they also could have simple but important beneficial roles, for example, in keeping the pores in our face unplugged.”
Though the mites have been previously thought of as parasites, Braig and colleagues are pushing for a reassessment of their role in our lives. Their help in keeping our skin healthy means we could consider them one of our symbionts – a lifelong partnership between two different species that benefits both.
Can we prevent their loss? It may be too late.
“I think that we cannot stop nature, and we shouldn’t,” said Perotti. “However, [our] healthy skin should suffice to maintain healthy populations for generations to come.”