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Host shift, geographic distribution and speciation of feather mites (Astigmata) in Brazil

Grant number: 18/21504-0
Support type:Scholarships abroad - Research Internship - Doctorate
Effective date (Start): May 06, 2019
Effective date (End): May 05, 2020
Field of knowledge:Biological Sciences - Zoology
Principal Investigator:José Paulo Leite Guadanucci
Grantee:Luiz Gustavo de Almeida Pedroso
Supervisor abroad: Pavel Klimov
Home Institution: Instituto de Biociências (IB). Universidade Estadual Paulista (UNESP). Campus de Rio Claro. Rio Claro , SP, Brazil
Local de pesquisa : University of Michigan, United States  
Associated to the scholarship:16/11671-1 - Geographic distribution, horizontal transfer and speciation in feather mites (Astigmata) in Brazil, BP.DR

Abstract

Feather mites (Analgoidea and Pterolichoidea) is the most species rich and abundant group of arthropods associated with birds. This diversity is due to a combination of two factors: the mites' (i) specialization to live in specific microhabitats on the bird's body (ii) high specificity to their hosts. Transmission of these mites to new hosts typically occurs when two bird individuals have physical contact to each other; most commonly transmission occurs vertically from parents to offspring during parental care. Brood parasitism is among bird behaviors that can affect this transmission pattern. Brood parasitic birds neither build nests nor have parental care. Therefore, it seems convincible that brood parasitic birds may facilitate mite horizontal transmission among multiple breeding host individuals (conspecific or belonging to different species), affecting host specificity of mites in this system. Even so, data from the few studies of feather mites from brood parasitic birds suggest that the interspecific transmission rarely occurs. However, the majority of these data refers to cuckoos (Cuculiformes) parasitizing passerines (Passeriformes), two phylogenetically distant groups that are known to harbor distinct feather mite faunas. It is more likely that the interspecific transmission in cases of brood parasitism occur between closely related birds. That is the case of cowbirds (Passeriformes: Icteridae: Molotrhus) from the Americas, brood parasitic passerines that parasitize several other passerines. However, almost nothing is known about their feather mites, as well as their geographical distribution. Given their host specificity, one would expect the mite's distribution to follow that of their hosts, however, there is some evidence that different bird populations can carry distinct mite fauna. To evaluate this distinctiveness, it is important to properly identify feather mite species, a task usually done using their morphology by skilled taxonomists. Molecular characterization of feather mites, providing species barcodes, has been helping to identify them, and showing that the presence of cryptic species is common in the group. Therefore, the genetic assessment of feather mites is an indispensable tool in biogeographic studies to properly identify feather mite species from different hosts and localities. By these reasons, this project proposes to investigate the feather mite fauna on the Shiny Cowbird Molothrus bonariensis, a common generalist brood parasitic bird in Brazil, and as well of some of their main passerine hosts, by characterizing their feather mite species using both molecular and morphology and evaluating the transmission of these feather mites on the Shiny Cowbird along their geographical distribution in Brazil. Preliminary results from museum skins include evidence of mite transference from hosts to shiny cowbird, and a scattered pattern of distribution of feather mites among populations of the rufous-collared sparrow (Zonotrichia capensis, Passerellidae) from South and Southeast Brazilian Regions and as well between Chilean populations.