A rare case of horizontal transfer in feather mites (Astigmata)

Feather mites are obligate ectocommensals associated with birds. They are generally transmitted yet in the nest by contact from parents to offspring, which results in a high specificity between them and their hosts, and often revealing intricate coevolutionary  processes. Feather mites rarely cause visible damage to their hosts, and in such cases, the host is often  flightless domestic birds. Recently, a new feather mite was described from Brazil, Allopsoroptoides galli Mironov 2013 (Astigmata: Psoroptoididae), this mite is very unusual for several reasons: 1) the host was the domestic chicken (Gallus gallus domesticus Linnaeus), which have their parasites long documented, especially for obvious economic reasons; 2) it was described as a new genus and species, being the first record of the family Psoroptoididae on birds of the order Galliformes;  3) it was found in huge populations and causing severe mange, which is expected to be caused by skin mites (e.g. Dermationidae), but not feather mites; 4) it soon became a huge economic/veterinary problem, since it attacked chickens in the city of Bastos, the largest producer of eggs of Brazil. No one knew where did this mite came from, but it seemed likely that the chickens acquired it from another bird, either wild or domestic, in a rare case of horizontal transfer. The question was: what was the primary host of this mite? In our investigation on feather mites from several non passerine birds in Brazil we happened to have found the natural host of A. galli, including and a new male morph (heteromorphic male) in these natural populations. Allopsoroptoides galli were recovered from several individuals of such bird species, from two distinct regions of Brazil. Those results are currently being compiled in a manuscript, along with speculations about the possible routes that might have enabled the horizontal transfer from the original hosts to the birds.