Dear Inaki,

As Leopoldo notes, we'll need photos to have an educated guess at the family. The most likely are also Macrochelidae, as Leopoldo mentioned.

The Macrochelidae-Drosophila (or numerous other flies) relationship is fairly well known, and a great example of where phoretic relationships sometimes turn a little bit nasty. Strict definitions of phoresy involve no parasitic aspect, but there are several cases where the relationship is clearly for transport between patchy habitats (usually where the immature stages of the phoront develop), yet the phoront takes a meal on the way. Definitions are too easily blurred.

Here's the abstract for one such paper on the topic where the macrochelids have significant negative impacts:

http://onlinelibrary.wiley.com/doi/10.2307/2265535/full

Don't take that paper as a generalisation, though, as most macrochelids are still thought to be purely phoretic, and are assumed as such until proven otherwise.

Kind regards, Owen.

Dear Inaki,

could you take some photo of the mites?

Some mites are exclusively phoretic, like Macrochelidae, but is necessary look how the specimens are attached to the flies.

How many legs has theses mites? 3 or 4?

You can send me emails, if you want... [email protected]

All the best

Dear Inaki,

As Leopoldo notes, we'll need photos to have an educated guess at the family. The most likely are also Macrochelidae, as Leopoldo mentioned.

The Macrochelidae-Drosophila (or numerous other flies) relationship is fairly well known, and a great example of where phoretic relationships sometimes turn a little bit nasty. Strict definitions of phoresy involve no parasitic aspect, but there are several cases where the relationship is clearly for transport between patchy habitats (usually where the immature stages of the phoront develop), yet the phoront takes a meal on the way. Definitions are too easily blurred.

Here's the abstract for one such paper on the topic where the macrochelids have significant negative impacts:

http://onlinelibrary.wiley.com/doi/10.2307/2265535/full

Don't take that paper as a generalisation, though, as most macrochelids are still thought to be purely phoretic, and are assumed as such until proven otherwise.

Kind regards, Owen.

Several Drosophila species routinely encounter mites that are ectoparasites of adults and / or predators of eggs and larvae. The first association between an ectoparasitic mite and a Drosophilid was described in detail by Polak & Markow (1995)  for the mite Macrocheles subbadius. In this link you can find more information about this:

49:660-9; http://dx.doi.org/10.2307/2410319

http://tandfonline.com/doi/full/10.1080/19336934.2016.1222998