Browsing by Author "Ippi, Silvina"

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    BREEDING BIOLOGY OF THE SOUTHERN HOUSE WREN ON CHILOE ISLAND, SOUTHERN CHILE
    (2012) Ippi, Silvina; Vasquez, Rodrigo A.; Moreno, Juan; Merino, Santiago; Villavicencio, Camila P.
    We studied the breeding biology of a Southern House Wren (Troglodytes aedon chilensis) population using nest boxes on Chiloe Island, southern Chile (41 degrees S) to make latitudinal comparisons at the intraspecific level. There were no significant differences in body size between adult males and females, although wings were significantly longer in males. Clutch size averaged 4.3 eggs per nest, and brood size was 3.9 nestlings. Egg size averaged 17.3 mm in length and 13.2 mm in width. Incubation and nestling periods averaged 16 days each. The Southern House Wren on Chiloe Island has a larger clutch size than in the tropics, but a smaller clutch size than populations at the same latitude in the Northern Hemisphere. The Southern House Wren has larger eggs and a longer incubation period but a similar nestling period as House Wrens in the Northern Hemisphere. Received 23 August 2011. Accepted 29 January 2012.
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    Haematozoa in forest birds from southern Chile
    (2008) Merino, Santiago; Moreno, Juan.; Vasquez, Rodrigo A.; Martinez, Javier; Sanchez-Monsalvez, Inocencia; Estades, Cristian F.; Ippi, Silvina; Sabat, Pablo; Rozzi, Ricardo; Mcgehee, Steven
    The existence of latitudinal gradients in species richness and their abundance is known for many free living organisms but few cases have been reported for parasitic diseases. In addition, asymmetries between the Northern and Southern Hemispheres in several characteristics may affect the distribution and diversity of species at all ecological levels. In this respect, we study the distribution of several genera of blood parasites infecting birds along a latitudinal gradient that includes the world's southernmost forests ecosystems. Birds were mist-netted and sampled for blood in localities across Chile ranging from 33 degrees S to 55 degrees S during the years 2003-06. Overall, 26 bird species were sampled and 27 parasite lineages were identified. The latter belonged to three genera: Plasmodium (8), Haemoproteus (8) and Leucocytozoon (11). We found a positive significant relationship between prevalence and latitude for Leucocytozoon lineages and a negative relationship for Haemoproteus, Plasmodium and mixed infections. However, we did not find a significant relationship between parasite diversity and latitude. We found 18 lineages infecting only one species of host, and 19 lineages appear in only one of the localities of sampling. This pattern implies that some parasite lineages may evolve in isolation in some species/localities. In addition, specificity at the host-family level was only found for Haemoproteus lineages infecting birds in the family Emberizidae. Individuals of the long distance migrant bird white-crested elaenia (Elaenia albiceps), were found infected by the same parasite lineages in localities separated by 20 degrees of latitude. Infections by these lineages were detected in other sedentary birds including juveniles and nestlings of different bird species. Therefore, long distance migrants are able to distort the presence of latitudinal gradients of diseases due to the potential role of migrants in spreading infections. Geographical gradients in prevalence of avian haematozoa differ between parasite genera and hemispheres, probably in relation to the existence of appropriate vector-parasite-host interactions.
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    Latitude does not influence cavity entrance orientation of South American avian excavators
    (OXFORD UNIV PRESS INC, 2021) Ojeda, Valeria; Schaaf, Alejandro; Altamirano, Tomas A.; Bonaparte, Bianca; Bragagnolo, Laura; Chazarreta, Laura; Cockle, Kristina; Dias, Raphael; Di Sallo, Facundo; Ibarra Eliessetch, José Tomás; Ippi, Silvina; Jauregui, Adrian; Jimenez, Jaime E.; Lammertink, Martjan; Lopez, Fernando; Montellano, Maria Gabriela Nunez; de la Pena, Martin; Rivera, Luis; Vivanco, Constanza; Santillan, Miguel; Soto, Gerardo E.; Vergara, Pablo M.; Wynia, Amy; Politi, Natalia
    In the Northern Hemisphere, several avian cavity excavators (e.g., woodpeckers) orient their cavities increasingly toward the equator as latitude increases (i.e. farther north), and it is proposed that they do so to take advantage of incident solar radiation at their nests. If latitude is a key driver of cavity orientations globally, this pattern should extend to the Southern Hemisphere. Here, we test the prediction that cavities are oriented increasingly northward at higher (i.e. colder) latitudes in the Southern Hemisphere and describe the preferred entrance direction(s) of 1,501 cavities excavated by 25 avian species (n = 22 Picidae, 2 Trogonidae, 1 Furnariidae) across 12 terrestrial ecoregions (15 degrees S to 55 degrees S) in South America. We used Bayesian projected normal mixed-effects models for circular data to examine the influence of latitude, and potential confounding factors, on cavity orientation. Also, a probability model-selection procedure was used to simultaneously examine multiple orientation hypotheses in each ecoregion to explore underlying cavity-orientation patterns. Contrary to predictions, and patterns from the Northern Hemisphere, birds did not orient their cavities more toward the equator with increasing latitude, suggesting that latitude may not be an important underlying selective force shaping excavation behavior in South America. Moreover, unimodal cavity-entrance orientations were not frequent among the ecoregions analyzed (only in 4 ecoregions), whereas bimodal (in 5 ecoregions) or uniform (in 3 ecoregions) orientations were also present, although many of these patterns were not very clear. Our results highlight the need to include data from under-studied biotas and regions to improve inferences at macroecological scales. Furthermore, we suggest a re-analysis of Northern Hemisphere cavity orientation patterns using a multi-model approach, and a more comprehensive assessment of the role of environmental factors as drivers of cavity orientation at different spatial scales in both hemispheres.
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    Molecular characterization of an ancient Hepatozoon species parasitizing the 'living fossil' marsupial 'Monito del Monte' Dromiciops gliroides from Chile
    (2009) Merino, Santiago; Vasquez, Rodrigo A.; Martinez, Javier; Luis Celis-Diez, Juan; Gutierrez-Jimenez, Leticia; Ippi, Silvina; Sanchez-Monsalvez, Inocencia; Martinez-de la Puente, Josue
    The Microbiotheriid Dromiciops gliroides, also known as 'Monito del Monte', is considered to be a threatened species and the only living representative of this group of South American marsupials. During the last few years, several blood samples from specimens of 'Monito del Monte' captured at Chiloe island in Chile have been investigated for blood parasites. Inspection of blood smears detected a Hepatozoon species infecting red blood cells. The sequences of DNA fragments corresponding to small subunit ribosomal RNA gene revealed two parasitic lineages belonging to Hepatozoon genus. These parasite lineages showed a basal position with respect to Hepatozoon species infecting rodents, reptiles, and amphibians but are phylogenetically distinct from Hepatozoon species infecting the order Carnivora. In addition, the Hepatozoon lineages infecting D. gliroides are also different from those infecting other micro-mammals living in sympatry, as well as from some that have been described to infect an Australian species of bandicoot. The potential vector of this parasite appears to be the host-specific tick Ixodes neuquenensis because the sequencing of a long amplicon determined the presence of one of the two lineages found in the marsupial. (C) 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 98, 568-576.