I am proud to present you today a case of phoresy on Dorcus parallelipipedus (stag beetle also found as parallelopipedus), family of Lucanidae… Obviously the mite presented here below is a deutonymph and not an adult stage ! It was found on the French territory.
Metagynella carpathica was firstly described by Balogh in 1943. The genera was firstly described by Belese in 1919. To finish with the classification, the family of Metagynuridae was erected by Baker & Wharton in 1952.
The only information I can find on the web concerning this species is the list of 14 species which should be currently identified for this genera… Nothing really more.
This species is probably a paneuropean species, this is my best guess… A nice hypothesis would be to say it follows its host, but I have no specific information to be sure of that. Dorcus Parallelipipedus is actually present in most of the French departments.
One caracteristic of this deutonymph is the “sort of” additionnal genital shield inserted between the anal and the sternal shield as you can see on the last photo. I noticed this intermediate shield only on this Uropodina species for the moment, but maybe some others Uropodina mites, in deutonymph stage, have such one ? This is to be checked…
According to Peter Masan, Dorcus Parallelipipedus is the primary host for the phoresy of Metagynella carpathica. The deutonymph can also use the famous Lucanus servus, as Boeing 747… Indeed, one may raise the question why a so tiny mite needs to use such a big mean of transportation… Obviously this is not a question of weight or size but rather a question of micro biotope this Boeing brings to… You have the answer to that question ? Larvae of Dorcus live in soft decaying wood of broad-leaved trees, is-it then probable to find some Metagynella in this biotope as well ?
One tip to seperate Metagynella carpathica from Metagynella paradoxa Berlese, 1919 : ventral shield setae (around anal opening) are three times longer than the sternal shield setae on Metagynella carpathica, approximatly same size for Metagynella paradoxa, detail which is not obvious on my last photo unfortunately (because of a problem of depth of field). There are obviously some more differences… I hope I will be in position to show you one day a deutonymph of Metagynella paradoxa !