Trombicula

{{short description|Genus of arachnids}} {{Redirect|Chigger|the fleas known as "jiggers"|Tunga penetrans{{!}}''Tunga penetrans''|other uses}} {{Redirect|Red bug}} {{Automatic taxobox |image=Harvest-mite-North America.jpg |image_alt=Larval harvest mite from North America |image_caption=Larval harvest mite from North America |taxon=Trombicula |authority=Berlese, 1905 |type_species=''Trombicula minor''<ref>{{cite journal |last1=Audy |first1=J. R. |last2=Nadchatram |first2=M. |last3=Loomis |first3=R. B. |last4=Traub |first4=R. |title=''Trombicula minor'' Berlese (Acarina, Trombiculidae): Designation of neotype with larval and post-larval stages from Malayan bats, and new name, ''Myotrombicula dilaratni'', for ''T. minor'', Cooreman, 1960 nec Berlese, 1905 |journal=Acarologia |date=1965 |volume=7 |issue=Suppl |pages=1–33 |url=https://www1.montpellier.inrae.fr/CBGP/acarologia/article.php?id=3722 }}</ref> |type_species_authority=Berlese, 1905 }}

'''''Trombicula''''', known as '''chiggers''', '''red bugs''', '''harvest mites''', '''scrub-itch mites''', or '''berry bugs''', are small arachnids<ref name=":0">{{Cite web |date=2021-04-21 |title=Chiggers, Jiggers, Harvest Mites, or Red Bugs |url=https://extension.okstate.edu/programs/digital-diagnostics/insects-and-arthropods/chiggers-jiggers-harvest-mites-or-red-bugs-trombicula-sp/ |access-date=2024-10-19 |website=Oklahoma State University |language=en}}</ref> (eight-legged arthropods) in the Trombiculidae family. In their larval stage, they attach to various animals and humans, then feed on skin, often causing itching and trombiculosis.<ref>{{Cite journal |last=Ramondetta |first=Alice |last2=Ribero |first2=Simone |last3=Peano |first3=Andrea |last4=Quaglino |first4=Pietro |last5=Broganelli |first5=Paolo |title=In Vivo Observation of Trombiculosis with Fluorescence–Advanced Videodermatoscopy |volume=26 |number=8 |date=August 2020 |journal=Emerging Infectious Diseases |publisher=CDC |url=https://wwwnc.cdc.gov/eid/article/26/8/20-0077_article |language=en-us |doi=10.3201/eid2608.200077|hdl=2318/1756188 |hdl-access=free |pmc=7392407 }}</ref> These relatives of ticks are nearly microscopic, measuring 0.4 mm (0.01 in), and have a chrome-orange hue. A common species of harvest mite in North America is ''Trombicula alfreddugesi''.

The larval mites feed on the skin cells, but not blood, of animals. The six-legged parasitic larva feeds on a large variety of creatures, including humans, rabbits, wallabies,<ref>{{cite journal |last1=Old |first1=J. M. |last2=Lowry |first2=J. |last3=Young |first3=L. J. |title=Scrub-itch mite (''Eutrombicula hirsti'') infection in the endangered bridled nailtail wallaby (''Onychogalea fraenata'') |journal=Australian Veterinary Journal |date=2009 |volume=87 |number=8 |pages=338-341 |doi=10.1111/j.1751-0813.2009.00462.x}}</ref> toads, box turtles, quail, and even some insects. After crawling onto their hosts, they inject digestive enzymes into the skin that break down skin cells.<ref name=":0" /> They do not actually "bite", but instead form a hole in the skin called a stylostome, and chew up tiny parts of the inner skin, thus causing severe irritation and swelling. The severe itching is accompanied by red pimple-like bumps (papules) or hives and skin rash or lesions on a sun-exposed area. For humans, itching usually occurs after the larvae detach from the skin.{{citation needed|date=December 2020}}

After feeding on their hosts, the larvae drop to the ground and become nymphs, then mature into adults, which have eight legs and are harmless to humans. In the postlarval stage, they are not parasitic and feed on plant materials. The females lay three to eight eggs in a clutch, usually on a leaf or under the roots of a plant, and die by autumn.{{citation needed|date=December 2020}}

==Distribution== {{Unreferenced section|date=December 2020}} Species in the genus ''Trombicula'' are found throughout the world. In Europe and North America, they tend to dwell in hot and humid climates. In more temperate regions, they are found only in summer. In France, for example, they are called ''aoûtat'', after ''août'' (August), ''vendangeon'', after ''vendange'' (harvest), or ''rouget'', after ''rouge'' (red).

In the United States, ''trombicula'' are found mostly in the southeast, the south, and the Midwest. They are rarely found in far northern areas, high mountains or deserts, however they can be found in the Great Lakes region.<ref>{{Cite web |author= |date=2020-04-22 |title=Where Do Chiggers Live? |url=https://chiggerex.com/bug-bite-101/where-do-chiggers-live/#:~:text=Missouri,%20Arkansas,%20Oklahoma,%20Nebraska,in%20the%20Great%20Lakes%20region. |access-date=2025-05-20 |website=Chiggerex |language=en-US}}</ref> They live in low, damp areas within forests and grasslands, as well as in drier environments where vegetation is low-growing but profuse, such as lawns, golf courses and parks. They are most numerous in early summer when grass, weeds and other vegetation are most prevalent. Harvest mites can also find their way into homes via human hosts who have passed through such areas.{{citation needed|date=November 2021}}

==Taxonomy== Species include:<ref>{{Cite web |website=IRMNG |date=2018 |title=''Trombicula'' Berlese, 1905 |url=http://www.irmng.org/aphia.php?p=taxdetails&id=1102956 |access-date=2019-01-16}}</ref> {{Columns-list|colwidth=32em| *''Trombicula agurensis'' {{small|(Goff & Easton, 1989)}} *''Trombicula alfreddugesi'' *''Trombicula asiatica'' {{small|(Wen & Corpuz-Raros, 1997)}} *''Trombicula blumbergi'' {{small|Asanuma, 1959}} *''Trombicula canestrinii'' {{small|(Buffa, 1899)}} *''Trombicula chejudoensis'' {{small|(Goff, 1984)}} *''Trombicula chiroptera'' {{small|Womersley & Heaslip, 1943}} *''Trombicula dasyphloea'' {{small|Domrow, 1959}} *''Trombicula dewae'' {{small|Domrow, 1964}} *''Trombicula dimolinae'' {{small|Audy, 1952}} *''Trombicula elegans'' {{small|Womersley, 1942}} *''Trombicula geckobia'' {{small|(Womersley, 1952)}} *''Trombicula hexasternalaea'' {{small|(Brown, 1997)}} *''Trombicula knighti'' {{small|Radford, 1954}} *''Trombicula koomori'' {{small|Sasa & Jameson, 1954}} *''Trombicula leegoffi'' {{small|(Brown, 1997)}} *''Trombicula leytensis'' {{small|(Brown, Goff & Nadchatram, 1988)}} *''Trombicula longwuensis'' {{small|Zhao & Wen, 1984}} *''Trombicula lukoschusi'' {{small|(Goff, 1983)}} *''Trombicula manjuyodensis'' {{small|(Brown, 1997)}} *''Trombicula meilingensis'' {{small|(Zhao, 1984)}} *''Trombicula minor'' {{small|Berlese, 1905}} *''Trombicula mitchellensis'' {{small|(Goff, 1983)}} *''Trombicula naultini'' {{small|Dumbleton, 1947}} *''Trombicula papua'' {{small|Domrow, 1978}} *''Trombicula patrizii'' {{small|Valle, 1952}} *''Trombicula pectinigera'' {{small|Lombardini, 1962}} *''Trombicula pyriformis'' {{small|(Wang & Song, 1990)}} *''Trombicula quadriensis'' {{small|Womersley & Heaslip, 1943}} *''Trombicula reticulata'' {{small|Vercammen-Grandjean & Nadchatram, 1963}} *''Trombicula rugosa'' {{small|(Goff, 1979)}} *''Trombicula signata'' {{small|Womersley, 1934}} *''Trombicula sinensis'' {{small|(Zhao & Qiu, 1979)}} *''Trombicula southcotti'' {{small|Womersley, 1952}} *''Trombicula spinosa'' {{small|Lombardini, 1952}} *''Trombicula thomasi'' {{small|(Oudemans)}} *''Trombicula thomsoni'' {{small|Womersley, 1954}} *''Trombicula tibbi'' {{small|Vercammen-Grandjean, 1965}} *''Trombicula tienmushanensis'' {{small|(Chu, 1964)}} *''Trombicula tsaochiensis'' {{small|(Chen & Hsu, 1963)}} *''Trombicula tuberculata'' {{small|Fauran, 1959}} *''Trombicula umboiensis'' {{small|(Goff, 1982)}} *''Trombicula victoriensis'' {{small|Audy & Womersley, 1957}} *''Trombicula vorca'' {{small|Traub & Audy, 1954}} *''Trombicula wenquana'' {{small|(Wen & Xiang, 1984)}} }}

==References== {{Reflist}}

==Further reading== * '' The World Book Encyclopedia'', 2000 ed. * ''Encyclopædia Britannica'', 2005 ed. {{subscription required}}. * {{cite book |author=Todd Ballantine |title=Tideland treasure: the naturalist's guide to the beaches and salt marshes of Hilton Head Island and the southeastern coast |publisher=University of South Carolina Press |location=Columbia, S.C |year=1991 |isbn=978-0-87249-795-5 |url-access=registration |url=https://archive.org/details/tidelandtreasure00ball }} * {{cite journal|last=Green|first=Sherri Deatherage|title=Give Chiggers The Brush|journal=Mother Earth News|issue=210|pages=93–98|date=June–July 2005 |url=http://www.motherearthnews.com/Natural-Health/2005-06-01/Avoid-Chiggers.aspx }}

==External links== * {{cite EB9 |wstitle = Harvest-Bug |volume= XI |last= |first= |author-link= | pages=500-501 |short=1}} * {{Cite EB1911 |wstitle= Harvest-bug |volume = 13 |last= |first= |author-link= |page=41 |short=1}} * [https://web.archive.org/web/20060928230657/http://mdc.mo.gov/nathis/arthopo/chiggers/ "Chiggers!" at Missouri Department of Conservation] * [https://hortnews.extension.iastate.edu/chiggers Iowa State University Department of Entomology Insect Information Note] * [https://www.medlineplus.gov/ency/article/001333.htm NIH Medline Plus] * [https://web.archive.org/web/20050530073632/http://ohioline.osu.edu/hyg-fact/2000/2100.html Ohio State University Extension Fact Sheet, Entomology, Chiggers, HYG-2100-98] * [http://www.the-piedpiper.co.uk/th5i.htm#harvestmite ''Trombicula autmunalis'']

Category:Trombiculidae