From cuckoos to chickens: a caught-in-the-act case of host shift in feather mites (Arachnida: Acari: Psoroptoididae).

Feather mites are highly specialized permanent ectosymbionts recorded from all recently recognized bird orders. These mites, specialized to live in the plumage of their hosts, rarely cause any visible damage to their specific hosts. Recently described feather mite Allopsoroptoides galli Mironov (Acariformes: Psoroptoididae) was reported to cause severe mange in chickens in Brazil, leading to unprecedented economic losses. Until now, the natural host of A. galli remained unknown. In this paper, we report its true wild host, the Guira cuckoo Guira guira (Cuculiformes: Cuculidae). In addition, a previously unknown heteromorphic form of males is described from the mite population distributed on its natural host. We also speculate a possible scenario by which this mite species could have been horizontally transferred from the wild populations of the natural host to the secondary hosts.