Syringophilid mites parasitising the crows and the competitive exclusion principle

Quill mites of the family Syringophilidae (Acariformes: Prostigmata) are one of the most species-rich groups of mite ectoparasites permanently associated with birds, characterised by high host specificity and strict microhabitat preferences. In this study, we examined 179 individuals representing 19 species of the genus Corvus (Passeriformes: Corvidae) to investigate the prevalence and host associations of syringophilid mites. Quill mites were detected in 31 hosts from 11 host species, with infestations restricted exclusively to the wing coverts and involving two species: Syringophiloidus glandarii and Corvisyringophilus krummi. These mites exhibited mutually exclusive host distributions, with the vast majority of corvid species infested by only one of the two mite species. The phylogenetic distribution of these mites across Corvus hosts, combined with their shared microhabitat and lack of co-occurrence, strongly supports historical interspecific competition and subsequent host specialisation, in accordance with the Competitive Exclusion Principle. S. glandarii appears to be the dominant lineage, infecting nine Corvus, while C. krummi was restricted to only three hosts. Only in Corvus albicollis were both mite species detected, though a limited sample size precludes definitive conclusions about stable co-occurrence. These findings highlight how ecological interactions, such as competition, can shape parasite distributions and drive specialisation, even among permanent and highly host-specific parasites. They provide insights into the factors governing host specificity and have implications for understanding ecological and evolutionary patterns in host-parasite systems.