Promiscuous specialists: Host specificity patterns among generalist louse flies

Abstract

Ectoparasites such as louse flies (Diptera: Hippoboscidae) have tendency for host specialization, which is driven by adaptation to host biology as well as competition avoidance between parasites of the same host. However, some louse fly species, especially in genera attacking birds, show wide range of suitable hosts. In the presented study, we have surveyed the current status of bird specific louse flies in Finland to provide comprehensive host association data to analyse the ecological requirements of the generalist species. A thorough sampling of 9342 birds, representing 134 species, recovered 576 specimens of louse flies, belonging to six species: Crataerina hirundinis, C. pallida, Ornithomya avicularia, O. chloropus, O. fringillina and Ornithophila metallica. Despite some overlapping hosts, the three Ornithomya species showed a notable pattern in their host preference, which was influenced not only by the host size but also by the habitat and host breeding strategy. We also provide DNA barcodes for ten Finnish species of Hippoboscidae, which can be used as a resource for species identification as well as metabarcoding studies in the future.

Avian Louse Flies and Their Trypanosomes: New Vectors, New Lineages and Host–Parasite Associations

“…Although the difference was significant, it was not clear-cut; the question persists whether specimens of O. fringillina found on resident birds emerged locally or switched hosts from northern migrants [9]. Interestingly, a recent study in Finland did not find any difference between three Ornithomya species abundances in relation to host migratory status [7], which might support the hypothesis that O. fringillina found in Czechia originated from northern breeding grounds, given that emerging louse flies attach to the first available avian host specimen, which then brings it to the south during its fall migration.…”

“…Louse fly species differ in their geographic distribution: O. fringillina and O. chloropus are typical for Northern Europe with fewer findings from Central and Southern Europe, whereas O. turdi and O. metallica have been found, rather, in the southern reaches of the northern hemisphere and are typical for Africa [2]. The host specificity of avian louse flies differs among species, ranging from high in O. biloba and S. hirundinis, which are essentially limited to a single host species, to low in Ornithomya avicularia and O. fringillina, which have been found on multiple host genera [6][7][8]. Individual louse flies can even switch their host species when birds are in close contact [9].…”

“…The host specificity of avian louse flies differs among species, ranging from high in O. biloba and S. hirundinis , which are essentially limited to a single host species, to low in Ornithomya avicularia and O. fringillina, which have been found on multiple host genera [ 6 , 7 , 8 ]. Individual louse flies can even switch their host species when birds are in close contact [ 9 ].…”

Contributions to our knowledge on avian louse flies (Hippoboscidae: Ornithomyinae) with the first European record of the African species Ornithoctona laticornis

“…Research on hippoboscids is flourishing nowadays, i.e. with investigations focusing on their ecology, evolution, and potential role in the transmission of pathogens [ 3 , 9 – 14 ].…”

“…Although studies on louse flies originating from Central [ 3 ] Northern [ 14 ], Southern [ 10 ], Western [ 15 ] and Eastern Europe [ 16 ] have also been conducted, only a few of these report long-term evaluations with continuous sample collection. The number of studies conducted on avian ectoparasites steadily increased in Hungary and in other Central European countries during the previous decade [ 2 , 3 , 12 , 17 , 18 ], but studies on ornithophilic hippoboscids appear to have been neglected compared to other arthropod vectors that are generally considered epidemiologically more important (i.e.…”