Odhneria odhneri Travassos, 1921 (Trematoda: Microphallidae) en aves playeras migratorias de Patagonia, Argentina

The aim of this paper is to describe Odhneria odhneri in migratory shorebirds at Patagonian sites. A total of 48 Calidris fuscicollis, 44 Calidris bairdii, and 5 Charadrius falklandicus from several areas in Argentinean Patagonia were examined. Adult specimens of O. odhneri were obtained from the intestinal cecae of C. bairdii (P=6.8, MI=30.3), and C. falklandicus (P=20, MI=17.5). Morphological and morphometric characteristics agree with those of previous records. This is the southernmost record for the trematode O. odhneri, and the first host record for C. bairdii and Ch. falklandicus. We propose that C. bairdii may act as a dispersing agent for O. odhneri between the America’s southern and northern hemispheres. Apparently, gastropod mollusks, crustaceans and birds are maintaining the life cycle of this species in Patagonia. The host, C. bairdii, has the potential of passing viable eggs of O. odhneri into the environment during their northward migration and onto their nesting sites during the boreal summer. This discovery broadens our knowledge about the range of hosts and the potential ways of dispersal of parasites along the American coast and, represents a valuable contribution to the general knowledge of shorebird parasites in South America.El objetivo de este trabajo es reportar la presencia del trematode Odhneria odhneri en aves playeras migratorias en la Patagonia argentina. Se examinaron un total de 48 Calidris fuscicollis, 44 Calidris bairdii y 5 Charadrius falklandicus de diferentes zonas de la Patagonia. Se obtuvieron adultos de O. odhneri de los ciegos intestinales de C. bairdii (P = 6,8; IM=30,3) y de Ch. falklandicus (P=20, IM=17,5). Las características morfológicas y morfométricas observadas coinciden con las registradas por autores previos. Este es el registro más austral de O. odhneri y el primer registro hospedatorio para C. bairdii y Ch. falklandicus. Calidris bairdii podría actuar como agente dispersor de O. odhneri entre América del Norte y América del Sur. Aparentemente, moluscos gasterópodos, crustáceos y aves estarían manteniendo el ciclo de vida de esta especie en la Patagonia. El hospedador C. bairdii tiene el potencial de dispersar huevos viables de O. odhneri en el ambiente durante su migración hacia el norte y en las áreas reproductivas durante el verano boreal. Estos hallazgos incrementan nuestro conocimiento sobre el rango hospedatorio y las formas potenciales de dispersión de parásitos a lo largo de la costa americana y representan una valiosa contribución al conocimiento general de los parásitos de aves playeras migratorias en América del Sur.Facultad de Ciencias Naturales y Muse

Odhneria odhneri Travassos, 1921 (Trematoda: Microphallidae) en aves playeras migratorias de Patagonia, Argentina

The aim of this paper is to describe Odhneria odhneri in migratory shorebirds at Patagonian sites. A total of 48 Calidris fuscicollis, 44 Calidris bairdii, and 5 Charadrius falklandicus from several areas in Argentinean Patagonia were examined. Adult specimens of O. odhneri were obtained from the intestinal cecae of C. bairdii (P=6.8, MI=30.3), and C. falklandicus (P=20, MI=17.5). Morphological and morphometric characteristics agree with those of previous records. This is the southernmost record for the trematode O. odhneri, and the first host record for C. bairdii and Ch. falklandicus. We propose that C. bairdii may act as a dispersing agent for O. odhneri between the America’s southern and northern hemispheres. Apparently, gastropod mollusks, crustaceans and birds are maintaining the life cycle of this species in Patagonia. The host, C. bairdii, has the potential of passing viable eggs of O. odhneri into the environment during their northward migration and onto their nesting sites during the boreal summer. This discovery broadens our knowledge about the range of hosts and the potential ways of dispersal of parasites along the American coast and, represents a valuable contribution to the general knowledge of shorebird parasites in South America.El objetivo de este trabajo es reportar la presencia del trematode Odhneria odhneri en aves playeras migratorias en la Patagonia argentina. Se examinaron un total de 48 Calidris fuscicollis, 44 Calidris bairdii y 5 Charadrius falklandicus de diferentes zonas de la Patagonia. Se obtuvieron adultos de O. odhneri de los ciegos intestinales de C. bairdii (P = 6,8; IM=30,3) y de Ch. falklandicus (P=20, IM=17,5). Las características morfológicas y morfométricas observadas coinciden con las registradas por autores previos. Este es el registro más austral de O. odhneri y el primer registro hospedatorio para C. bairdii y Ch. falklandicus. Calidris bairdii podría actuar como agente dispersor de O. odhneri entre América del Norte y América del Sur. Aparentemente, moluscos gasterópodos, crustáceos y aves estarían manteniendo el ciclo de vida de esta especie en la Patagonia. El hospedador C. bairdii tiene el potencial de dispersar huevos viables de O. odhneri en el ambiente durante su migración hacia el norte y en las áreas reproductivas durante el verano boreal. Estos hallazgos incrementan nuestro conocimiento sobre el rango hospedatorio y las formas potenciales de dispersión de parásitos a lo largo de la costa americana y representan una valiosa contribución al conocimiento general de los parásitos de aves playeras migratorias en América del Sur.Facultad de Ciencias Naturales y Muse

Seabird ticks (<i>Ixodes uriae</i>) distribution along the Antarctic Peninsula

The distribution of the tick Ixodes uriae is studied in the South Shetlands and different locations along the Antarctic Peninsula. Ticks were found beneath stones close to penguin rookeries of chinstrap, gentoo and adelie penguin, although no individuals were found parasitized. Our results showed that ticks are not distributed evenly along the Antarctic Peninsula being more common and abundant in the northern part with relative abundances of ticks ranging from 1 to 57 individuals per stone and from 2 to 26% of the stone inspected. Ticks are probably absent in the south.Centro de Estudios Parasitológicos y de Vectore

Leukocyte profile in the Red Knot (<i>Calidris canutus rufa</i>) in Patagonia, Argentina

El principal componente del sistema inmunitario de los vertebrados está mediado por los leucocitos. En aves existen cinco tipos: heterófilos, eosinófilos, basófilos, linfocitos y monocitos. El objetivo de este trabajo es presentar los conteos leucocitarios obtenidos a partir del análisis de frotis sanguíneos para un ave migratoria de larga distancia, el Playero Rojizo (Calidris canutus rufa) en el sitio de invernada Río Grande, Tierra del Fuego, y durante la escala trófica en Bahía San Antonio, Río Negro, Argentina. Como se observa en general para las aves, los heterófilos y los linfocitos predominaron en ambos sitios, mientras que el resto de los leucocitos se observaron en menor proporción.The immune response in vertebrates is primarily mediated by leukocytes. Types of leukocytes in birds are basophils, heterophils, eosinophils, lymphocytes and monocytes. The leukocyte profile obtained from blood smear analyses is reported for a long distance migrant, the Red Knot (<i>Calidris canutus rufa</i>) during its wintering at Rio Grande, Tierra del Fuego, and its stopover site at San Antonio Bay, Río Negro, Argentina. Heterophils and lymphocytes were the most abundant leukocytes in both sites, while the other leukocytes showed lower proportions

Physiological differences between two overlapped breeding Antarctic penguins in a global change perspective

This article is an invited contribution on Life in Antarctica: Boundaries and Gradients in a Changing Environment as the main theme of the XIth SCAR Biology Symposium. J.-M. Gili and R. Zapata Guardiola (Guest Editors).Global change has affected the Antarctic Peninsula influencing the abundance of krill, one of the main preys of penguins. In areas where breeding penguin populations overlap, species with a more diverse diet have generally been less affected than krill-specialist species, which have shown population declines. Human activities can add to these changes, as penguins are sensitive to anthropic impacts such as contamination. Our objective was to assess whether selected physiological parameters of Adélie and Gentoo penguins reflect their contrasting population trends in a colony located at Punta Stranger (25 de Mayo Island/King George, South Shetland Islands) where they breed sympatrically. During 2012, we assessed the leukocyte profile, heterophil to lymphocyte ratio (H/L), erythrocytic nuclear abnormalities (ENAs), hematocrit, biochemical profile, and a measure of immune function (bacterial agglutination) in adults and chicks of both species. Higher values of ENAs, indicative of genotoxic damage caused by contaminants, are in accordance with a greater sensitivity to ongoing global changes by Adélie penguins. Levels of cholesterol and triglycerides strengthen this idea since individuals could be investing more resources in energy reserves to successfully cope with challenging environmental conditions during the breeding season. The remaining physiological parameters did not provide a clear picture. Furthermore, some results could be related to differences in diet. Gentoos show greater prey diversity than Adélie penguins, incorporating a richer parasite fauna, which could explain their higher heterophils and H/L. The physiological parameters measured here serve as baseline for a sustained monitoring of these rapidly changing populations. Further physiological variables, including stress hormone and indices of oxidative stress, remain to be assessed as potential indicators of population susceptibility to global change in this system.AB was supported by the project CTM2011-24425.Peer Reviewe

Prey consumed by red knot (<i>Calidris canutus</i>) in San Julián Bay, Santa Cruz, Argentina

El objetivo de este trabajo fue determinar las presas consumidas por el Playero Rojizo (<i>Calidris canutus</i>). Se analizaron 30 heces y 2 egagrópilas recolectadas en febrero de 2002 en Bahía San Julián, provincia de Santa Cruz, Argentina. Las aves se alimentaron de la almeja Darina solenoides (90% de las heces) y de anfípodos de una especie indeterminada (40%). El perímetro de la talla máxima de almeja ingerida por los playeros no superó los 30 mm, límite umbral de tamaño de presa que puede ingerir el Playero Rojizo. La biomasa promedio encontrada en las heces fue mayor que las halladas en otras localidades.The objective of this study was to determine prey consumed by Red Knot (<i>Calidris canutus</i>). We analyzed 30 faeces and 2 pellets gathered in February 2002 in San Julián Bay, Santa Cruz Province, Argentina. The birds fed upon the clam Darina solenoides (90% of the faeces) and upon an undetermined amphipod species (40%). Perimeter of the maximum size of ingested clam did not overcome 30 mm, threshold limit of prey size that can be ingested by Red Knots. Mean faeces biomass was higher than those found in other locations

Leukocyte counts in three sympatric pack-ice seal species from the western Antarctic Peninsula

Global warming, and its consequences, constitute one of the main stressors for organisms worldwide, affecting different factors such as the geographic distribution and the abundance of parasites, which in turn can affect the immune system of their hosts, and vice versa. Therefore, it is important to have baseline information on immune parameters of organisms in order to make future comparisons within this changing ecological context. Here, we report on the leukocyte counts of the Antarctic pack ice seals, the crabeater (Lobodon carcinophaga), Weddell (Leptonychotes weddellii) and leopard (Hydrurga leptonyx) seals, sampled off the western Antarctic Peninsula. We captured and sampled seals in the pack ice off the Danco Coast, Antarctica in the austral summers, January to March, of 2015 and 2016. The leukocyte counts, along with the counts of each different leukocyte (e.g., basophil, neutrophil, eosinophil, lymphocyte and monocyte), were made from blood smears viewed under the light microscope. As a potential stress indicator, we examined whether seals with lice, so presumably under greater physiological stress, had changes in leukocyte counts, including higher ratios of neutrophil-to-lymphocytes (N/L ratio). Leukocyte counts were different among the seal species. While crabeater and Weddell seals had higher neutrophil counts, followed by lymphocyte counts, leopard seals had the reverse pattern. Basophil, eosinophil, and lymphocyte counts were higher in the leopard seal, while the N/L ratio, as well as the neutrophil counts, were higher for the crabeater seal. We show, for the Weddell seal, that the animals with lice were more likely to have higher N/L ratios. This suggests that future research into the potential of the N/L index as a stress indicator, that incorporates additional stress parameters including cortisol concentrations, oxidative damage, as well as other measures of immune function, is warranted for the pack ice seals. Our results are a first step towards establishing leukocyte count baselines for the Antarctic pack ice seals off the western Antarctic Peninsula.Facultad de Ciencias Naturales y Muse

Leukocyte counts in different populations of Antarctic Pygoscelid penguins along the Antarctic Peninsula

The Antarctic Peninsula is one of the areas where the climate is changing at the fastest pace, having several effects on the populations of pygoscelid penguins. Few studies have analysed the variation in immune parameters of antarctic birds in a geographical context; thus, analyses of geographical differences in the immune components of wild pygoscelid penguins are still scarce. Leukocyte counts in birds provide information on their immunity and physiological stress. The objective of this study was to analyse the leukocyte counts in penguins of the genus Pygoscelis (gentoo, Adélie and chinstrap penguins), covering sites along the South Shetland Islands and some islands on the west coast of the Antarctic Peninsula. Our results revealed differences in the number of heterophils and eosinophils and in the heterophil/lymphocyte ratio in the northeastern populations of gentoo and Adélie penguins as compared to the rest of the colonies studied. The results contribute to better understanding of the variations in physiological parameters of penguins related to a geographical context.This study was funded by the Spanish Ministry of Science and Innovation (Grant CGL2007-60369 and CTM2011-24427).Peer Reviewe

Sex matters? Association between foraging behaviour, diet, and physiology in Magellanic penguins

Ecological segregation has been documented between males and females in diferent populations of seabirds. Moreover, foraging behaviour and diet have been associated with markers of oxidative status, and have been suggested to be a driver of sex-biased oxidative costs of reproduction in wild marine vertebrates. Nevertheless, the ecological role of sex driving such associations has been little studied. We, therefore, examined whether foraging habitat (δ13C), trophic level (δ15N), dietary antioxidants (retinol and α-tocopherol) and oxidative status (antioxidant capacity and oxidative damage, ROM) were ecologically segregated by sex in Magellanic penguins (Spheniscus magellanicus) breeding in Peninsula Valdés (Argentina) visualizing the isotopic, dietary antioxidant, and oxidative status Bayesian spaces as proxies for ecological niches. Our results suggest that specifc sexual segregation by ecological niche partially drives the relation between foraging, dietary antioxidants, and oxidative status. The dietary antioxidant niche showed females with extremely low α-tocopherol levels relative to males, although retinol values seemed to be similar between sexes. Higher trophic levels preys (high δ15N) were positively associated with α-tocopherol in males suggesting that their greater dependence on the Argentinian hake (a benthopelagic fsh rich in α-tocopherol) led to a higher absorption of specifc dietary antioxidants than females. In addition, a positive relation between α-tocopherol and ROMs in males suggested that their benthic foraging was associated with greater oxidative damage, and that higher levels of alpha-tocopherol in benthopelagic fsh were not sufcient to prevent higher levels of oxidative damage associated with the consumption of such fsh. Overall, sex-biased dietary antioxidant niche linked with sex-specifc ecological segregation.This study was funded by the Spanish Ministry of Economy and Competitiveness (CTM2011-24427 and CTM2015-64720) and Multiannual Research Projects-CONICET (PIP 112–20110100680). RCC held a Spanish Ministry of Economy and Competitiveness FPI and mobility grants (BES2012-059299 and EEBB-I-14–07887), and EC had a CONICET doctoral fellowship.Peer reviewe