21 research outputs found
Comparative phylogeography of parasitic Laelaps mites contribute new insights into the specialist-generalist variation hypothesis (SGVH)
BACKGROUND: The specialist-generalist variation hypothesis (SGVH) in parasites suggests that, due to patchiness in
habitat (host availability), specialist species will show more subdivided population structure when compared to
generalist species. In addition, since specialist species are more prone to local stochastic extinction events with their
hosts, they will show lower levels of intraspecific genetic diversity when compared to more generalist.
RESULTS: To test the wider applicability of the SGVH we compared 337 cytochrome oxidase I mitochondrial DNA and
268 nuclear tropomyosin DNA sequenced fragments derived from two co-distributed Laelaps mite species and
compared the data to 294 COI mtDNA sequences derived from the respective hosts Rhabdomys dilectus, R. bechuanae,
Mastomys coucha and M. natalensis. In support of the SGVH, the generalist L. muricola was characterized by a high
mtDNA haplotypic diversity of 0.97 (±0.00) and a low level of population differentiation (mtDNA Fst= 0.56, p < 0.05;
nuDNA Fst = 0.33, P < 0.05) while the specialist L. giganteus was overall characterized by a lower haplotypic diversity of
0.77 (±0.03) and comparatively higher levels of population differentiation (mtDNA Fst = 0.87, P < 0.05; nuDNA Fst = 0.48,
P < 0.05). When the two specialist L. giganteus lineages, which occur on two different Rhabdomys species, are
respectively compared to the generalist parasite, L. muricola, the SGVH is not fully supported. One of the specialist L.
giganteus species occurring on R. dilectus shows similar low levels of population differentiation (mtDNA Fst= 0.53, P < 0.
05; nuDNA Fst= 0.12, P < 0.05) than that found for the generalist L. muricola. This finding can be correlated to
differences in host dispersal: R. bechuanae populations are characterized by a differentiated mtDNA Fst of 0.79 (P < 0.05)
while R. dilectus populations are less structured with a mtDNA Fst= 0.18 (P < 0.05).
CONCLUSION: These findings suggest that in ectoparasites, host specificity and the vagility of the host are both
important drivers for parasite dispersal. It is proposed that the SGHV hypothesis should also incorporate reference to
host dispersal since in our case only the specialist species who occur on less mobile hosts showed more subdivided
population structure when compared to generalist species
Specific association between the mites Androlaelaps fahrenholzi (Acari: Laelapidae) and birds Premnoplex brunnescens in Costa Rica: possible evidence of a recent host switch.
Androlaelaps fahrenholzi is a common, cosmopolitan mite constituting a species complex. This mite is found in nests or on mammal hosts and occasionally on birds. The specific host association between A. fahrenholzi-like mites and Premnoplex brunnescens in Costa Rica is reported here. Adults (females and males), deutonymphs and protonymphs were found on 14 P. brunnescens examined (prevalence was 100 %) with mean abundance 42 (2?222). The nest environment plays an important role in the evolution of parasites and could explain the evolutionary path of Laelapinae towards parasitism. We hypothesize that the colonization of P. brunnescens took place in this context quite recently, from sympatrically living rodents. Morphology and ecology of A. fahrenholzi from P. brunnescens may constitute at least a new variation of A. fahrenholzi, and possibly a new species.Fil: Lareschi, Marcela. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico La Plata. Centro de Estudios ParasitolĂłgicos y de Vectores (i); Argentina. Universidad Nacional de La Plata; ArgentinaFil: Literak, Ivan. University of Veterinary and Pharmaceutical Sciences; RepĂșblica ChecaFil: Capek, Miroslav. Academy of Sciences of the Czech Republic; RepĂșblica ChecaFil: Sychra, Oldrich. University of Veterinary and Pharmaceutical Sciences; RepĂșblica Chec
Phthiraptera and Gamasida Parasites of Columbina picui (Temminck) (Columbiformes: Columbidae) in the State of Rio Grande do Sul, Southern Brazil
Thirty-two specimens of Columbina picui (picui ground-dove) were examined, and a collection of arthropods was made by washing the external surface of the body and the nasal cavity. The species in the order Phthiraptera found and their respective prevalences, mean abundance and mean intensity were: Columbicola passerinae (84.4%; 10.3; 12.2), Hohorstiella passerinae (21.9%; 0.7; 3.1) and Physconelloides eurysema (3.1%; 0.1; 2). The gamasid mites found in the birds and their respective prevalences, mean abundance and mean intensity were: Pellonyssus marui (31.3%; 1.2; 3.9), Ornithonyssus bursa (15.6%; 0.2. ;1.2) and Mesonyssus sp. (6.3%; 0.1; 1). Columbicola passerinae, H. passerinae, P. eurysema, O. bursa, P. marui and Mesonyssus sp. were recorded for the first time infecting C. picui in Brazil. Except for O. bursa, the other species are reported for the first time in the state of Rio Grande do Sul, Brazil