Chiggers

Definition

The parasitic larval stage of trombiculid mites (family Trombiculidae), tiny arachnids that attach to vertebrate skin and feed on liquefied epidermal tissue, causing intense itching and the dermatological condition trombiculosis. Despite common misidentification as insects, chiggers are larval mites—relatives of ticks—with only six legs in this stage, acquiring the full eight legs of adult arachnids after molting. The term typically refers to the genus Trombicula and related genera, not to the free-living nymphal or adult stages, which are predatory on other microarthropods and do not parasitize vertebrates.

Etymology

Origin uncertain; possibly from British dialect chigoe (chigoe flea, Tunga penetrans) via folk etymology, though chiggers and chigoes are unrelated organisms.

Example

Field biologists in the southeastern United States often apply permethrin to clothing and tuck pants into socks to prevent Trombicula alfreddugesi larvae from attaching at sock lines and waistbands during summer vegetation surveys.

Synonyms

• harvest mites
• Red bugs
• scrub-itch mites
• berry bugs

Related Terms

• Trombiculidae
• trombiculosis
• mite
• arachnid
• Ectoparasite
• chigoe

Usage Notes

Strictly refers to the larval stage only; adult trombiculids are harmless soil predators. Frequently confused with chigoe fleas (Tunga penetrans), which are insects that burrow into skin. The term is primarily North American vernacular; British English favors 'harvest mites.'