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

I depend on support, please buy me a coffee
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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/

Posters | Global Soil Partnership | Food and Agriculture Organization of the United Nations

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