A new chigger mite: Helenicula naresuani

Mites of the family Trombiculidae are also called berry bugs or harvest mites. The best known representatives are perhaps the chiggers. These are the species  that bite their host in their larval stage and cause irritation, usually with severe itching and dermatitis.

Chiggers attach to the host, pierce the skin, inject enzymes into the bite wound that digest cellular contents, and then suck up the digested tissue through a tube. They do not burrow into the skin or suck blood, as is commonly assumed. Itching from a chigger bite may not develop until 1-2 days after the bite, so the victim may not associate the specific exposure with the bite itself.

The new species was discovered as part of a broad sampling effort across 11 provinces in Thailand, and it was found on rodents. There are now 99 known species of chiggers in Thailand. This chigger is named after Naresuan, the king of the Ayutthaya Kingdom (in what is now modern Thailand) from 1590 to 1605.

For the experts: Chigger mites of Thailand were studied on the basis of larvae collected from 19 small mammal species (17 species of Rodentia, 1 species of Erinaceomorpha, and 1 species of Scandentia) and revision of published data. Samples of 38 trombiculid species were collected from 11 provinces. Three new species were described: Trombiculindus kosapani sp. nov., Helenicula naresuani sp. nov., and Walchia chavali sp. nov. Ten species were recorded in Thailand for the first time: Leptotrombidium sialkotense Vercammen-Grandjean and Langston, 1976; Leptotrombidium subangulare Wen and Xiang, 1984; Leptotrombidium tenompaki Stekolnikov, 2013; Leptotrombidium turdicola Vercammen-Grandjean and Langston, 1976; Leptotrombidium yunlingense Yu, Yang, Zhang and Hu, 1981; Lorillatum hekouensis Yu, Chen and Lin, 1996; Helenicula pilosa (Abonnenc and Taufflieb, 1957); Gahrliepia xiaowoi Wen and Xiang, 1984; Walchia minuscuta Chen, 1978; and Walchia ventralis (Womersley, 1952). In all, 99 chigger mite species were considered; the presence of 93 species was established in Thailand by original data or properly documented records in the scientific literature. Evidence for 64 species records of 147 from a previous checklist of Thai chiggers (Tanskul 1993) remains unknown. Distribution of chigger species by geographical regions of Thailand is discussed.