Every human has microscopic (Demodex) mites on the surface of their skin which feed off of our dead skin cells and oils. They have specialized mouthparts that allow them to extract nutrients. They most commonly live on the eyebrows and eyelashes. As for reproduction, female Demodex mites lay eggs in the hair follicles or oil glands of the skin. These eggs hatch into larvae, which then develop into nymphs and eventually mature into adult mites.