#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

Scanning electron microscope #SEM details of a #mite (#Histiostomatidae, #Astigmata, #Acariformes) from rotting #lemonfruits in #Italy (Sorrento, from 2006).

The #copulationopening of this species consists of a forwardly curved half "dome", which seemingly protects the opening hole from being covered by dirt from above. In this Histiostoma sp. it is useless as females reproduce parthenogenetically (#thelytoky).
© #StefanFWirth Berlin 2024

My full #blogarticle on X:
https://x.com/wirthstef/status/1840364206966579512?t=G04uRpmjMOM1nvKMZNR5yQ&s=19