Nov 252015
 

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 !

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Nov 132015
 

Hello friendship of mites !

To continue the series of feather mites, here is the nearly famous feather mite of the common pigeon, for those who care about pigeons or doves at least… Its sweety little name is Falculifer rostratus (Buchholz, 1869) , from the family of Falculiferidae.

 

It feeds on keratin and prefers the flight feathers of wings (better taste or more minerals ?). It makes holes in the plumage and thus can hamper the flight. A favoured place for various species of such feather mites is the junction of barbs with the feather shaft.

According to federmiben.de, this species can be found on the following bird species :

Collared Dove (Streptopelia decaocto)
Crested Pigeon (Ocyphaps lophotes)
Stock Dove (Columba oenas)
African Collared Dove (Streptopelia roseogrisea)
Housepigeon (Columba livia)
Trocaz Pigeon (Columba trocaz)
Woodpigeon (Columba palumbus)

On this same site you will find interesting information about the lifecycle of a feather mite.

Wandering around on the internet, I found the following specialised publications on this species :

  • Fine Structure of the Feather Mite Falculifer rostratus (Buchholz 1869) (Acari, Falculiferidae). 150 pages & 88 figures on this species, it is much probably a very interesting publication but unfortunatly far too expensive for me.
  • Population density and male polymorphism in the feather mite Falculifer rostratus (Acari: Falculiferidae), H. C. Proctor , G. Williams, D. H. Clayton

I went through this second publication and discovered an interesting phenomenon in the world of mites : the male polymorphism ! It occurs in Mesostigmata (Macrochelidae for example), in Prostigmata but also in Astigmata. The purpose of the study was to determine if the population density has an impact on the ratio of homeomorphic and heteromorphic males, as this can be observed for Sancassania berlesei. Well, the conclusion is not that straightforward because the notion of population density should be observed maybe preferably at the feather level, and not at the whole pigeon level…

In the case of Falculifer rostratus, the heteromorphic male should have leg I, II and the movable digit of chelicera greatly elongated. Is it the case for the shown mite ? I will tell you something… I do not know, I am even not 100% sure I am showing you a male (O my Goodness !), but maybe You know ?

Anyway if you are looking for information to get rid of these parasites for your belowed pigeons, I recommand you to check other sites… this one is dedicated to taxonomy, scientific studies and iconography of parasites (oriented on determination).

Thanks for your interest !

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Nov 082015
 

This new mite is obiously a Mesostigmata belonging to the Uropodina Cohort.

I feel a bit uncomfortable with this Polyaspinus, considering that some authors class it in the Polyaspididae family, and others in Trachytidae family. Who owns the truth ? Where is the truth ? M. Kontschan, if you could help us your are welcome !

I read in my favorite book, A Manual of Acarology, that Polyaspinus are denizens of tree holes, forest litter and mostly restricted to the Northern hemisphere. There would be only 7 species for this genus according to the same author. Polyaspinus are phoretic species in deutonymph stage.

 

My species, well, is not fully identified, assuming that I have no key for Europe for this genus… If you happen to have some key for this genus, let us know, and share it ! You can also tell me what is the real species of the specimen I am showing you now. Maybe it is nor Polyaspinus cylindricus (firstly described by Berlese, 1916) neither Polyaspinus nicolae (furtherly described by Hirschmann, 1992).. who knows ? Personnaly I have some doubts when I look at my specimen, and the difficulties is to distinguish when morphological differences are only intra-specific or not !

The vertex ends with a funny shape as visible on the detail of prodorsum, my specimen has two small bulb at the very end of the vertex bearing the setae. But these two setae are not visible on my photo.

Please pay attention to the cerotegument, visible on the cuticle of the body and the legs. This sticking wax agglomerates tiny soil particles and fungus spores. By the way I am personnaly convinced that mites participate in the dispersion of spores !

This Polyaspinus is also a very good example to show what is a called platelet or scutella, a very tiny shields (here in raws in lateral position). If you look carefully you will see two pores and one seta per scutella.

Why I am not convinced for Polyaspinus cylindricus or Polyaspinus nicolae ? Well… for the following reasons :

  • I do not understand exactly the differenciation made by Hirschmann. If we follow the criteria of a central pygidial shield shorter than the lateral ones then it is Polyaspinus nicolae,
  • But in my specimen the scutella, in the two lateral rows and both sides, have the same size but different shapes, this is not the case for the specimen described in my documentation (Annotationes zoologicae et Botanicae N223, Slovenske Narodne Muzeum v Bratislave, Peter Masan, 2001),
  • There are some bulbs at several places on the dorsum of my specimen, I cannot see on drawings of both species (same documentation),
  • The genital shield is also significantly different…

So I submit my case to the world of acarologists, as a bottle in the ocean…

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Nov 012015
 

Here is another feather mite which was firstly named by Edouard Louis Trouessart in 1885. This is the first image of this species on Google image at the time being.

Trouessartia bifurcata (Trouessart, 1885) is a member of the Trouessartiidae family created by the same person (you would have never guessed…). This is today still considered as a valid species by Fauna Europea.

 

Here are microscopic photos taken from a microscopic mount of the MNHN, Paris. One long seta of the “tail” is unfortunatly broken, but this problem frequently occurs during the mount.

The inscriptions on the slide shows :

  • Name of species : Trouessartia bifurcata
  • Name of host : Acrocephalus paludicola (aquatic warbler)
  • Locality : France
  • Date of collection : unknown
  • Reference of slide : 42E4
  • Collection : Trouessart
  • Sex : male
  • Other reference : trt-38

Unfortunatly nothing about the mounting medium…

Trouessartia is a large genera which is parasiting primarily passeriforms. Acrocephalus paludicola is a Passeriform of the family of Acrocephalidae (aquatic warbler in English, phragmite aquatique in French). A taxonomic work has been done for the family of Trouessartiidae by Orwig (1968) and Santana (1976), I would very much appreciate to get this synthesis, if you have it !

For this species you would say directly bifurcata means the tail is bifurcated in this species, unfortunatly I fear that this caracteristic is shared with a number of other Trouessartia species…

Trouessartia bifurcata is not yet illustrated in this remarquable site on feather mite : federmilben.de. Nevertheless, this site indicates other bird species which can host Trouessartia bifurcata :

  • Barred Warbler (Sylvia nisoria)
  • Garden Warbler (Sylvia borin)
  • Common Whitethroat (Sylvia communis)
  • Lesser Whitethroat (Sylvia curruca)

If you have examples of Trouessartiidae to share with us, do not hesitate to send them !

Our thanks go to MNHN Paris for granting a free access to the collection.

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