#histiostoma — Public Fediverse posts

In my #SEM #photos, the #mouthparts of the #mite #Histiostoma sp. (Histiostoma #feroniarum complex), found on #rotting #lemons in southern #Italy (Sorrento), look like menacing #aliens. In reality, however, they are merely #fungusfeeders that often prefer a side of #bacterial emulsion as a "sauce" (Wirth, 2024).
© #StefanFWirth 26

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Reference:
S. F. Wirth, poster publication (2024): https://www.fao.org/fileadmin/user_upload/GSP/GSID24/Posters/Theme_1/lemon_decomposing_mites_version_2_Dr_Stefan_F_Wirth.pdf

Photos
© S. F. Wirth, SEM

#Astigmata #mites are characterized by a separation between egg and #copulationopening. In Histiostomatidae, the latter is located dorsally. Its #morphology can remarkably vary depending on the species. The #myrmecophilous #Histiostoma sp. ex lab colony of #Solenopsis #invicta has a bulb shaped one with very small opening.
©#StefanFWirth

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reference
S.F. Wirth & J.C. Moser (2010)
https://doi.org/10.1051/acarologia/20101979

#Photos
©S.F.Wirth, #SEM, 2009/2026

#mites of the #Astigmata (#Acariformes) are soft-skinned. Their thin #cuticle is sensitive to #drought, which is why they avoid leaving their mostly #moist #fungus- and bacteria-rich #habitats. For the purpose of #dispersal, a modified instar, the #deutonymph, with stronger cuticle and other specific #adaptations #evolved, performing #phoresy, the transport most often via larger arthropods.
© #StefanFWirth, July 2026, Berlin

#Photo:
#Adult female of #Histiostoma sp. © Stefan F. Wirth

#Mites of the #Astigmata (#Sarcoptiformes, #Acariformes), such as #Histiostomatidae shown here, practice #direct #spermtransfer via #copulatoryorgans in #males and #females. An #evolutionary #innovation derived from #spermatophoretransfer without copulation in #Oribatidmites. Advantage: a huge egg can develop and new sperm can be stored simultaneously.
©#StefanFWirth, July 2026

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#SEM #photos
©S.F.Wirth: #Histiostoma #palustre, H. sp, #aedeagus

In #Astigmata #mites #ovipore and #copulatory organ are spatially separated, an #evolutionary innovation that allows #spermtransfer, its #storage in the receptaculum seminis, and #egglaying to occur simultaneously. W. Witalinski (2014) described the #oogenetic and #inseminatory (secondary) #system.©#StefanFWirth

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reference
W.Witalinski (2014)
https://doi.org/10.1016/j.asd.2014.04.003

#SEM#photos
©S.F.Wirth, #Histiostoma #maritimum,H. #palustre, H. cf. #pulchrum

Under adverse conditions, #astigmatid #mites develop a special nymphal stage: the #deutonymph (shown here: #Histiostoma #sapromyzarum, living specimen). It's a #heteromorphic stage that serves the purpose of #phoretictransport and a result of a #metamorphosis into a juvenile stage lacking a mouth but possessing gonadal primordia and a rudimentary midgut.
©#StefanFWirth

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Further reading
P.B. Klimov et al. (2021)
https://doi.org/10.1038/s41598-021-94367-2

#Photos
©S.F.Wirth,2026

Years ago, with my then-host in the USA, John C. Moser, I described the #myrmecophilous #phoretic #mite #Histiostoma #blomquisti as a new #species (S.F.Wirth & J.C.Moser, 2010).
In a recent #sciencecomm. #article, I reconstructed its #biology, being found on active #queens of ant #Solenopsis #invicta, from my current perspective (S.F.Wirth,2026).
©#StefanFWirth 2026

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Ref
https://doi.org/10.1051/acarologia/20101979

https://biologe.wordpress.com/2026/03/09/diversity-of-ant-research-about-the-phoretic-mite-histiostoma-blomquisti-on-solenopsis-invicta-queens-and-about-ant-queens-producing-exclusively-other-ant-queens-in-the-japanese-species-temnothorax-k/

#Photos
©S F.Wirth

Very small #mites are subject of my research as they are associated with other arthropods (#phoretic#dispersal), and even #influence the #microclimate in their #habitats in complex ways, by fungal #spore transport+chemical fungal growth regulation via own #fungicides. #Histiostoma #sapromyzarum is subject of my current#Behance project exploring it also #aestheticslly.

©#StefanFWirth

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Behance S F.Wirth
https://www.behance.net/gallery/244398767/Fragile-Transparency

#Ascospores are the result of the sexual reproduction of #Ascomycota #fungi, being single celled or #septate. There are different ways of #dispersal. One option is obligatory or accidental transport via animals, such as #mites. The photos show mating mites of #Histiostoma sp. seemingly covered with 4 chambered ascospores. J. Karakehian et al. (2021) studied "Methods for observing, culturing, and studying living ascospores".

© #StefanFWirth 2025

Ref
https://doi.org/10.5943/ajom/4/2/1

#SEM
©S.F.Wirth

#Mites of the #Histiostomatidae (#Astigmata) not only have highly #modified #mouthparts (see photo) that form a #filterfeeding organ, but their #copulatoryposition is also an #evolutionary #modification. Other Astigmata mate back-to-back, while Histiostomatidae have the male riding on top of the female, head over head. See here the dorsal #copulationopening of a #female of #Histiostoma sp..

©#StefanFWirth 2025

Further reading S.F. Wirth ( 2024)
https://www.fao.org/global-soil-partnership/gsid24/posters/en/

SEMphotos ©S.F. Wirth

#Mites of the #Histiostomatidae (#Astigmata, #Acariformes) are adapted due to #evolution to form #species with #small sizes of about 200-400 micrometers in adults. Their thin #cuticles and modified #filterfeeding #mouthparts for #fungus-bacterial #food intake allowed their #radiation within shortliving moist and bacteria/fungus rich habitats.

©#StefanFWirth October 2025,

Photos
Females of #Histiostoma sp., from #sapropel #mud around gravel pit ponds, #Berlin #Grunewald, 2019, New edit 2025

#Socialinsect #nests are #ecosystems with a #diversity of #organisms.
In #leafcutterant #Atta #texana nests, mite #Histiostoma #bakeri reduces harmful #fungi in detritus chambers (S.F. Wirth & J.C. Moser 2008).
A. Panchal et al. (2025) found #termite #Odontotermes #obesus to reduce harmful fungi from its food #funguscultivar using fungicides of #bacteria.

©#StefanFWirth

Ref
(2008)
Proceed. 6th EURAAC

(2025)
https://doi.org/10.1126/science.adr2713

pic
O. obesus, Nikhil More, 2020,
https://creativecommons.org/licenses/by-sa/4.0/deed.en

In #Astigmata #mites #chemosensitive/#tactile interactions take precedence over #visualsenses. #Histiostomatidae (here, #Histiostoma sp., H. feroniarum complex, ex #rottinglemons, #Italy) communicate using various #pheromones/allomones produced by the #opisthonotal #glands. See here a #glandularopening on the upper hindbody #(hysterosoma) of a #female, #SEM.

© #StefanFWirth, 2025

Reference:

Stefan F. Wirth about a lemon mite (2024): https://www.fao.org/global-soil-partnership/gsid24/posters/en/

Photos:
© SFWirth Bln, 2006-25

When #animals #carry other organisms: If it is a regular dispersal strategy it can be #phoresy. When phoretic #mites, such as soil mite #Histiostoma sp. (#Astigmata) here, disperse #fungi themselves, this can be hyperphoresy. The mating adult mites in my #SEM carry #macroconidia, presumably of Ascomycota. Adult mites aren't the phoretic stage, thus they can disperse a fungus only within their limited #habitat.
©#StefanFWirth Berlin 2025

Reference
S. F. Wirth (2023)
https://www.fao.org/fileadmin/user_upload/GSP/GSOIL4N/GSOIL4N-Posters/ID_167.pdf

My #SEM shows a female of the #mite #Histiostoma sp. (H. feroniarum-complex, special fixation) on #rottenlemon from Italy, #feeding a mixture of #fungi and #bacteria. It is seen from above and displays the symmetrically #fenestrated #proterosomashield that i.a. stabilizes muscle origins and still needs research. I published research information on that mite as poster #publication.

© #StefanFWirth Berlin (2006-) 2025

Poster S. F. Wirth, FAO, Global Soil Partners. (2024)
https://www.fao.org/global-soil-partnership/gsid24/posters/en/

This is the first #freeliving #instar of a #mite from the #Histiostomatidae (#Astigmata, #Acariformes) : named the #larva and being characterized by having only #3pairs of #legs, which is a phylogenetically old character. #Specific and thus #apomorphic for Histiostomatidae is that there is a #dorsalpattern of #sclerites, differing between subtaxa. The photo shows the species #Histiostoma sp. (H. feroniarum-complex) from rotting #lemonfruits in Italy (Sorrento).

© #StefanFWirth Berlin 2024

#Lemon #tree #Citrus × #limon, its fruits, their insecticidal effect, about tree-#endophytic #organisms (#microbiota) and the rotting #fruits as #habitats for #phoretic #mites (#Histiostomatidae). #Ecology, #phoresy, #phoresis, #soil, #decomposition
© #StefanFWirth Berlin2024

My #blog on #biologe + #literature:

wp.me/p2l6XU-1TF

Photos 2+3: details of small #lemontree from plant trade Berlin, 1: #Histiostoma sp. (H. #feroniarum-complex) from lemons in #Sorrento (#Italy,2006) © S. F. Wirth 2024

What is a #mite of the #Histiostomatidae doing in nests of an #antnest? About behavior, dispersal, #phoresy, life strategy. A 2008 study about the life strategy of mite #Histiostoma #bakeri (Histiostomatidae) in nests of the leafcutting ant #Atta #texana.
According to this, the desired location of the mites for mating and reproduction is the detritus chambers of the ant nest.
© #StefanFWirth Berlin 2023

Paper Wirth & Moser (2008), short summary and PDF for download: https://wp.me/p2l6XU-1Mt