Itch mite (Sarcoptic mange mite)

Human skin, specifically the stratum corneum (outer layer of epidermis)

Dissolved skin cells and extracellular fluid

Female mites burrow into the skin to lay eggs; they are typically most active at night, which coincides with increased itching in hosts.

Causes scabies, a highly contagious skin infestation characterized by intense itching and rashes; can lead to secondary bacterial infections from scratching; no known ecosystem benefits.