Harvest mites

(genus Trombicula; also known as red bugs, trombiculid mites, scrub-itch mites, berry bugs or, in their larval stage, as chiggers) are mites in the family Trombiculidae that live in forests and grasslands.

• In their larval stage they attach to various animals including humans and feed on skin, often causing itching. These relatives of spiders are nearly microscopic measuring 0.4 mm (1/100 of an inch) and have a chrome-orange hue. A common species of Harvest mite in Northern America is Trombicula alfreddugesi; in the UK the most prevalent Harvest mite is Trombicula autumnalis.

 

Life cycle

• Harvest mite larvae are small, red immatures between the egg and nymph stages, which have not yet become adult mites. They are usually microscopic. The larvae often live in berry patches, tall grass and weeds, woodland edges, pine straw, leaves, and tree bark, or in typical habitats of their hosts (especially rodents).
  The larval mites feed on the skin cells, but not blood, of animals, including humans. The six-legged parasitic larva feeds on a large variety of creatures including humans, rabbits, toads, box turtles, quail, and even some insects. After crawling onto their host, they inject digestive enzymes into the skin that break down skin cells. They do not actually "bite," but instead form a hole in the skin and chew up tiny parts of the inner skin, thus causing severe irritation and swelling. The severe itching is accompanied with red pimple-like bumps (papules) or hives and skin rash or lesion on a sun-exposed area. For humans, itching usually occurs after the larvae detach from the skin. Chiggers are known for spreading from host to host.