Mastozoología Neotropical ISSN: 0327-9383 [email protected] Sociedad Argentina para el Estudio de los Mamíferos Argentina Navone, Graciela T.; Notarnicola, Juliana; Nava, Santiago; Robles, M. del Rosario; Galliari, Carlos; Lareschi, Marcela ARTHROPODS AND HELMINTHS ASSEMBLAGE IN SIGMODONTINE RODENTS FROM WETLANDS OF THE RIO DE LA PLATA, ARGENTINA Mastozoología Neotropical, vol. 16, núm. 1, enero-junio, 2009, pp. 121-133 Sociedad Argentina para el Estudio de los Mamíferos Tucumán, Argentina Available in: http://www.redalyc.org/articulo.oa?id=45712055011 How to cite Complete issue Scientific Information System More information about this article Network of Scientific Journals from Latin America, the Caribbean, Spain and Portugal Journal's homepage in redalyc.org Non-profit academic project, developed under the open access initiative Mastozoología Neotropical, 16(1):121-133, Mendoza, 2009 ISSN 0327-9383 ©SAREM, 2009 Versión on-line ISSN 1666-0536 http://www.sarem.org.ar ARTHROPODS AND HELMINTHS ASSEMBLAGE IN SIGMODONTINE RODENTS FROM WETLANDS OF THE RIO DE LA PLATA, ARGENTINA Graciela T. Navone1*, Juliana Notarnicola1, Santiago Nava2, M. del Rosario Robles1, Carlos Galliari1, and Marcela Lareschi1 1 Centro de Estudios Parasitológicos y de Vectores, Calle 2 N° 584, 1900 La Plata, Buenos Aires, Argentina. CEPAVE (CCT- CONICET- La Plata; UNLP) *[Correspondencia: <[email protected]>] 2 Instituto Nacional de Tecnología Agropecuaria INTA, Rafaela, Santa Fé, Argentina. ABSTRACT: The assemblage of arthropods and helminths, present in sigmodontine ro- dents (Cricetidae) from a broad wetland area of the Río de la Plata, Argentina, was studied. A total of 250 sigmodontines were captured during a two-year sampling period: Scapteromys aquaticus and Oxymycterus rufus were the most abundant hosts, followed by Oligoryzomys nigripes, Akodon azarae, Oligoryzomys flavescens, and Deltamys kempi. There were 33102 parasites collected, corresponding with Rhopalopsyllidae fleas (Siphonaptera), Hoplopleuridae lice (Phtiraptera), Laelapidae and Macronyssidae mites, Ixodidae ticks, and Trombiculidae chiggers (Acari), the trematodes Echinostomidae, Microphallidae, and Dicrocoelidae, the flatworm Ciclophyllidea, the nematods Trichuridae, Spiruridae, Onchocercidae, Physalopteridae, Aspidoderidae, Oxyuridae, and Nippostrongylinae, and the thorny-headed worm Acanthocephala. A list of arthropods and helminths species associated with each rodent species was given, as well as the prevalence and mean abundance. New host and geographic records were provided. The phenogram of the relationships of the parasite assemblages showed a high value of similarity between both species of Oligoryzomys, and between S. aquaticus and O. rufus. Variation of the values observed in the prevalence and the mean abundance of the host-parasite association suggests that there could be environ- mental barriers between the rodent populations, or that differential behavior of the host species (i.e. use of microhabitats, tropics behaviors) may influence these indexes. This knowledge may be used to determine targets for biological conservation and ecological impact of parasitism in the area. RESUMEN: Ensamble de artrópodos y helmintos parásitos en roedores sigmodontinos de los humedales del Río de la Plata, Argentina. Se estudió el ensamble parasitario de artrópodos y helmintos en roedores sigmodontinos (Cricetidae) en una franja de los humedales del Río de la Plata, Argentina. Se capturaron un total de 250 roedores sigmodontinos durante dos años consecutivos. Scapteromys aquaticus y Oxymycterus rufus fueron los más abundantes, seguidos por Oligoryzomys nigripes, Akodon azarae, Oligoryzomys flavescens, y Deltamys kempi. Se colectaron 33102 parásitos correspondientes a pulgas Rhopalopsyllidae (Siphonaptera), piojos Hoplopleuridae (Phtiraptera), ácaros Laelapidae y Macronyssidae, garrapatas Ixodidae, y bichos colorados Trombiculidae (Ac- ari), trematodes Echinostomidae, Microphallidae y Dicrocoelidae, cestodes Ciclophyllidea, nematodes Trichuridae, Spiruridae, Onchocercidae, Physalopteridae, Aspidoderidae, Oxyuridae y Nippostrongylinae, y los gusanos espinosos Acanthocephala. Se detalla una lista de las asociaciones de artrópodos y helmintos con cada especie hospedadora y se dan las prevalencias y abundancias medias. Además, se mencionan nuevos registros geográficos y hospedatorios. Los fenogramas de similitud de los ensambles parasitarios mostraron altos valores entre ambas especies de Oligoryzomys y entre S. aquaticus y O. rufus. Variaciones en los valores de prevalencia y abundancia media observados en las asociaciones parásito-hospedador sugieren que podrían estar actuando barreras ambientales 122 Mastozoología Neotropical, 16(1):121-133, Mendoza, 2009 GT Navone et al. http://www.sarem.org.ar entre las poblaciones hospedadoras, o que el comportamiento diferencial de las especies hospedadoras (i.e. uso de microhabitat, comportamiento trófico) puede estar influenciando dichos índices. Este conocimiento puede ser utilizado para identificar objetivos en la conservación y en el impacto ecológico del parasitismo en el área. Key words. Ectoparasites. Endoparasites. Río de La Plata. Rodents. Wetlands. Palabras clave. Ectoparásitos. Endoparásitos. Humedales. Río de La Plata. Roedores. INTRODUCTION ever, most of these surveys in the wetland area deal with descriptions of new species and/or Colonization of a host species by a parasite records of new hosts. Lareschi (2000) de- species is a process that may take several scribed some parasite associations between generations. Its success depends on different arthropods and hosts (i. e. sigmodontine ro- factors, such as environmental conditions, age dents) from the Selva Marginal de Punta Lara, and sex of the host, or more complex ones, near the Río de la Plata. Moreover, Lareschi for example, the behavior and immune status et al. (2004, 2007) showed the association of the hosts (Poulin and Morand, 2004). Once between the arthropods Hoplopleura travassosi the host-parasite association is known, varia- Werneck, Gigantolaelaps wolffsohni tions of them can be detected as the presence- (Oudemans), and Ornithonyssus bacoti (Hirst) absence of the above mentioned association with the filarioid worms Litomosoides or variation in the indexes—prevalence, mean bonaerensis Notarnicola, Bain and Navone and abundance. Using the variability of these fea- L. oxymycteri Notarnicola, Bain and Navone, tures, it is possible to predict what host har- and suggested their potential role as natural bors what parasite (Poulin and Morand, 2004). vectors of the filarioids. In terrestrial habitats, environmental factors can The aim of this research is to study the also cause variation in parasite species rich- parasite assemblage (arthropods and helminths) ness among populations of the same host spe- present in the most representative sigmodontine cies (Krasnov et al., 1997). rodent species from a wetland area of the Río The wetlands of the Río de la Plata, Argen- de la Plata, Buenos Aires Province, to provide tina, comprise a forest of complex structure the prevalence and mean abundance of the with numerous species and strata (Menalled host-parasite associations, and to analyze the and Adamoli, 1995). This area is included in similarity of the parasite communities. New the Ecoregion of Delta and Paraná Island host-parasite associations are mentioned. (Burkart et al., 1999). Wild rodents are the most representative mammals in the area, and MATERIALS AND METHODS at least 10 species are mentioned for the wet- lands living in different microhabitats ranging Studied area.—Samples were carried out on an from flooded to grassland habitats (Massoia, area besides the Río de la Plata, from Reserva 1961; Ringuelet, 1962; 1981; Gomez Villafañe Natural de Hudson (34° 45’ S, 58° 06’ W) to La et al., 2005). Several host-parasites associa- Balandra (34° 56’ S, 57° 42’ W). The area is char- acterized by lowlands throughout the margin of tions were reported from these rodents in the the Río de la Plata intercalated with coastal strips area. Among them, ticks, mites, fleas, nema- emerging from water. It displays periods of floods todes, and flatworms are mentioned (Sutton, originated mainly by the local rain, the dripping 1974; Castro et al., 1987; Sutton and Lunaschi, water from temporal creeks, and periodical south- 1994; Lareschi, 1996; Suriano and Navone, east winds, plus the freshet of the Río de la Plata 1996; Lareschi and Mauri, 1998; Notarnicola (Dascanio et al., 1994). A succession of vegetal et al., 2000; Robles and Navone, 2006). How- communities are disposed from the margin to in- PARASITES ASSEMBLAGE IN SIGMODONTINES 123 ner lands as follows; rushes, riverside grasslands, on the basis of the values of P and MA of 45 riverside scrubland, «sauzales», wetland forest, species or parasite species group (MVSP software). straw grassland, and grass pseudo-steppe, produc- ing heterogeneous microhabitats in the coast RESULTS (Cabrera and Dawson, 1944; Barrios and Moschione, 1993). A total of 250 rodents belonging to six spe- Hosts.—Rodents were trapped from April 1995 cies of Sigmodontinae were trapped in the area: to October 1996 during 30 trapping session. Cap- Scapteromys aquaticus Thomas (n = 130), tures were carried out by two of the authors (GN Oxymycterus rufus (Fischer) (n = 58), and ML) in accordance with regulations and poli- Oligoryzomys flavescens (Waterhouse) (n = cies of the Dirección de Administración y Difusión 27), Akodon azarae (Fischer) (n = 23), Conservacionista