- The mites are about 0.3mm long and are found in the hair follicles of the face and nipples, including the eyelids and eyelashes.
- They have many more cells at a young age compared to their adult stage.
They are invisible to the naked eye. Microscopic mites, called “Demodex”, are constantly present on our skin. These little beasts, which are increasingly numerous in adults as the pores become larger, were passed on to us at birth. “Follicular mites are the only metazoans that live continuously on the epidermis of human beings”, said researchers from Bangor University in Wales. Those found on the face are called “Demodex folliculorum”.
Mites active at night
In a recent study published in the journal Molecular Biology and Evolution, scientists have analyzed the DNA of these mites for the first time to learn more about their secret lives, specifically their body characteristics and evolutionary future. For the purposes of their work, they used the sequencing of the genome of “Demodex folliculorum”.
According to the team, these tiny beasts, colonizing skin pores, mate on our face while we sleep. For this, they move between the hair follicles. According to the results, these mites feed on the sebum naturally released by the cells of the pores. Put simply, they help our pores open up and get rid of oils that contribute to blemishes and infections.
The authors revealed that the existence of these mites was isolated. “We found that these mites behave very differently from parasites. We found that these mites have a different arrangement of body part genes than other similar species due to their adaptation to a sheltered life at inside the pores. These changes to their DNA resulted in unusual body characteristics and behaviors.” Alejandra Perotti, a professor who co-led the research, said in a statement.
Endangered due to genetic loss
Genome sequencing revealed that the permanent association of “Demodex folliculorum” with their host resulted in genetic reduction. Clearly, this decrease is caused due to their isolated existence, lack of exposure to outside threats, and encounters with other mites with different genes. This genetic reduction would cause the mites to become organisms “simplified” and they could soon become one with human beings.
This genetic loss is also the cause of their nocturnal behavior. Dust mites have no UV protection and have lost the gene that allows them to be awakened by daylight. The unique disposition of their genes is also responsible for their unusual mating habits. Their reproductive organs moved forward.
Dust mites are not the cause of skin diseases
For a long time, some researchers had assumed that mites had no anuses and had to accumulate all their faeces throughout their lives before releasing them when they died, causing skin inflammation. But this recent work has confirmed that these little beasts do have an anus and have therefore been unfairly accused of being responsible for many skin conditions.
“Mites have been blamed for many things. Their long association with humans might suggest they may also have simple but important beneficial roles, for example, keeping the pores in our face unclogged,” concluded Henk Braig, co-lead author of the study.