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Passeriformes colonization and related ectoparasites in insular and mainland populations
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Resumo(s)
The isolation process of Island parasite populations has revealed a remarkable set of changes in their characteristics, termed parasite island syndromes. Improving knowledge of the effect of insularity on parasite communities from hosts with different time scales of isolation, is essential for understanding the processes involved in the evolution of parasitism and how the period of host isolation, manifests itself on parasite island syndromes.
This thesis addresses the ectoparasite communities of Turdus merula, Sylvia atricapilla, Fringilla coelebs and Erithacus rubecula, from mainland Portugal and three Islands of the Azores Archipelago, specifically São Miguel, Terceira and Flores. The Azores Archipelago, geographically positioned as the Northernmost Archipelago of Macaronesia and composed of nine Oceanic Islands recognized as biodiversity hotspots, make it an important area to study the patterns of insular evolution. Live birds were captured with mist nets and sampled for presence of ectoparasites using the modified fumigation chamber method. Traditional methods were used for microscopic identification of hippoboscid flies, fleas and chewing lice. Insular ectoparasite communities of host species were compared with continental communities based on parasite island syndromes (species richness, prevalence and host specificity). Additionally, insular species richness was compared between the area of the Islands and their distance from the mainland.
The present study showed that ectoparasites do not failed to establish to the Azores Islands, and furthermore, the diversity of the ectoparasites communities, especially to chewing lice, was clearly enriched on the Azores Islands, with more 3 species than mainland birds. The results also revealed a high insular prevalence of ectoparasites. In regards to host specificity, insular ectoparasites have retained the characteristic specificity of the mainland. Even though island syndromes were not correlated with Island area and distance from the mainland, the overall findings indicate that characteristics associated with the Islands, specifically ambient humidity, the parasites, mainly ability to tolerate ambient humidity, and the hosts, particularly population densities, body size, and nest sanitation, influence the structuring of insular ectoparasite assemblages. Parasite island syndromes were especially notable in T. merula, a bird with two colonization events on the Azores Islands, which suggest that the host isolation on Islands may influence the evolution of insular parasite communities.
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Palavras-chave
Ectoparasitas Síndromes insulares de parasitas Passeriformes Ilhas dos Açores Portugal Ectoparasites Parasite island syndromes Passerine birds Azores Islands