Composition of the Araneae (Arachnida) fauna of the provincial Iberá Reserve, Corrientes, Argentina. A survey of the spider community composition and diversity was carried out in grasslands and woods in three localities: Colonia Pellegrini, Paraje Galarza and Estancia Rincón (iberá province Reserve). Pit fall traps, leaf litter sifting, foliage beating, hand collecting and sweep nets were used. Shannon's diversity index, evenness, Berger-Parker's dominance index, β and γ diversity were calculated, and a checklist of spider fauna was compiled. Species richness was estimated by Chao 1, Chao 2, first and second order Jack-knife. A total of 4 138 spiders grouped into 150 species from 33 families of Araneomorphae and two species from two families of Mygalomorphae were collected. Five species are new records for Argentina and eleven for Corrientes province. Araneidae was the most abundant family (39.8%), followed by Salticidae (10.9%), Anyphaenidae (7.9%), Tetragnathidae (7.4%), and Lycosidae (5.5%). The other families represented less than 5% of the total catch. The web-builder guild had the highest number of specimens and the highest richness index. The abundance, observed richness, Shannon diversity and evenness indexes were highest in Colonia Pellegrini woodland and Paraje Galarza grassland. Alpha diversity represented 89% of the gamma; the remaining 11% corresponded to β diversity. According to the indexes, between 67% and 97% of the existing spider fauna was represented in the collected specimens from iberá. Rev. Biol. Trop. 57 (1-2): 339-351. Epub 2009 June 30.

Spider diversity in cultures of Citrus sinensis (Rutaceae) in Corrientes province, Argentina. Spiders are predators that reduce insect pest populations in agroecosystems. In spite that the presence of spider assemblages has been described in different crop plants, no reports have been done for Citrus species in Argentina. We studied the spider community associated with cultures of Citrus sinensis in the province of Corrientes, Argentina, in two plots (AM1 irrigated and AM2 unirrigated) of 0.82 hectares each. Spiders were collected monthly by using pitfall traps, hand capture, agitation of foliage and sieving of soil litter. A total of 7 174 specimens were collected (33 families, 44 genera and 200 species/morphospecies). The AM1 recorded 3 811 individuals (33 families, 179 species/morphospecies) and AM2 3 363 individuals (31 families, 174 species/morphospecies). November, December and January showed the highest abundance in both plots. A total of 70% of collected spiders were juveniles. Eight families were the most abundant and represented 75% of spiders collected in both plots, the largest being Lycosidae. We identified eight guilds in both plots, for which the ground runners resulted the most abundant (AM1 n=1341, s=39, n=999 AM2, s=33), followed by orb weavers (AM1 n=637, s=36; AM2 n=552, s=33), the stalkers (AM1 n=471, s=43, AM2 n=453, s=47) and the space webbuilders (AM1 n=446, s=23; AM2 n=342, s=25). The analysis of alpha diversity in both plots (AM1H'=4.161, J'=0.802; AM2 H'=4.184, J'=0.811) showed no significant differences (t=1.083 p=0.279). The linear dependences model was the one with the best fit results, where the species observed were more than estimated. Clench model estimated 90.9% of the spiders observed in the unit with irrigation and 90.6% in the unit without irrigation.

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Domestic and peridomestic triatomine colonization, T. infestans infection rate and human seropositives to Trypanosoma cruzi in rural areas of Empedrado Department, Corrientes, Argentina, were carried out. Methods used in order to search the triatomines, to determine them systematically, to obtain their infection rates and the human seropositives, were the same applied in a previous report. From 100 households characterized, 53.0% had mud walls, laminated zinc or cardboard combined with other elements were used in 37.5% of the roofs, and 83.0% had earthen floors. Presence of domestic animais sleeping inside houses was detected in 91.0% of human dwellings. Domestic infestation by T. infestans was 29.0% and 1.0% by T. sordida. Other T. infestans entomological indexes recorded were: natural infection index = 23, colonization index = 75 and dispersion index = 54,5. T. sordida was found in 12.1% of peridomestic structures while T. infestans was detected in 2.4%. General prevalence from 298 human sera analized by Indirect Hemagglutination and Indirect Immunofluorescence Antibody Tests, was 32.2%. A high percentage of positive serology (23.7%) was found among 0-10 years old, wich represent the age group of higher transmission risk.

Se llevõ a cabo un estúdio epidemiológicopara obtener u n p a n o ra m a general de la transmisión doméstica del T ry p an o so m a cru zi en ãreas rurales dei Departamento San Miguel, Conientes, Argentina. Se investigaron 100 viviendas precarias, 50,0% de las mismas resultó infestado p o r T riatom a infestans y 1,0% p o r T. sórd ida, citãndose p o r prim era vez para la provinda de Comentes la colonización domiciliaria de esta especie. El 23,1% de T. infestans estaba infectado p o r T. cru zi. La seroprevalencia de 3 8 8 pacientes analizados p o r hemaglutinacíôn indirecta e inmunofluorescencia indirecta f u e 23,4% , destacãndose el alto índice (12,9% ) constatado en menores de 10 anos. Losporcentajes de seropositividad aumentaron con la edad, alcanzãndose 50,0% d e infectados en tre los 3 1 -4 0 anos. La infestaciõn dom éstica por'Y . in f e s ta n s , la prevalencia hum ana de seropositivos a lT. cruzi y las condiciones dep reca ried a d en que se desenvuelve la vida de los pobladores revelan la vigência de la endem ia chagãsica en el área estudiada.Palabras-claves: Triatominos. Infestaciõn. T. cru zi. Seroprevalencia. Conientes.

Con el objeto de verificar la presencia de T. sordida Stäl 1859, en ecotopos urbanos de la ciudad de Corrientes, Argentina se tomaron como base un habitat extradomiciliario y la vivienda humana. En el palomar situado en el Parque Mitre fue realizado un censo completo de población de T. sordida para lo cual fueron disecados 400 nidos de paloma (Columbia livia). Los ejemplares de triatominos detectados en las viviendas fueron enviados por los pobladores al Laboratorio de Artrópodos. Los triatominos fueron determinados sistemáticamente y por clase de edad. La materia fecal de los mismos fue examinada al microscopio para la identificación del Trypanosoma cruzi. En el palomar se colectaron: 6 huevos, 45 ninfas de primer estadío, 110 ninfas de segundo estadío, 226 ninfas de tercer estadío, 303 ninfas de cuarto estadío, 1.103 ninfas de quinto estadío, 12 hembras y 11 machos. Se constató la presencia de esta especie en 27 viviendas localizadas en 8 barrios de la Ciudad. Se capturaron 13 huevos, 33 ninfas de diferentes estadíos, 27 hembras y 9 machos, totalizando 82 individuos. Ningún triatomino resultó infectado por T. cruzi. Los adultos de T. sordida se desplazaron hacia el domicilio en primavera y verano. Es de destacar que el 33% del material hallado en las viviendas correspondió a hembras. Se ha comprobado la adaptación de T. sordida a un habitat extradomiciliario y su tendencia a invadir la vivienda humana, hecho que se debería ser tenido en cuenta en los programas de control de vectores.

An entomological and serological survey was performed in three localities of the Department of Concepción, Province of Corrientes, Argentina in 1998 and1999, to Key words: Triatoma infestans -Triatoma sordida -infestation -infection -seroprevalence -ArgentinaIn rural areas of Corrientes Province, Triatoma infestans (Klug 1834) is mainly found indoors and is also present in peridomestic premises (Bar et al. 1992(Bar et al. , 1996b(Bar et al. , 1997.T. sordida (Stål 1859) colonizes wild biotopes (Bar et al. 1996a) as well as artificial ecotopes in peridomestic areas, sometimes coexisting with T. infestans and even established inside a rural house (Bar et al. 1992(Bar et al. , 1996b. In Corrientes city it frequently invades houses and a large colony was captured in an urban ecotope (Bar et al. 1993).Although intradomestic colonies of T. infestans have been eliminated from some areas of Corrientes province, T. sordida may replace it as a domestic vector. Integration of extradomestic triatomines to domestic transmission cycles has been occasionally reported in Minas Gerais, Brazil (Diotaiuti et al. 1993).Anthropic environmental modification, mainly the replacement of natural forest by cultivated land, harvesting of wood and uncontrolled grazing may produce a concentration of wild mammals and triatomines in the peridomicile, generating local transmission cycles of Trypanosoma cruzi. Those foci can provide invading vectors to the domicile that can eventually carry trypanosomes (Wisnivesky-Colli et al. 1993). The peridomicile may represent a transition environment for triatomines coming from the wild and facilitate their domiciliation process (Gajate et al. 1996).An important flood affected Corrientes Province in 1998, as a consequence of the El Niño phenomenon, which made the owners of the dwellings leave them temporarily. Most of the houses were rebuilt afterwards. This entire situation contributed to the increase of the environmental disturbance.In order to increase our knowledge on the ecology of domestic and wild triatomines, an entomological and serological survey was carried out in rural settlements of the Department of Concepción, Corrientes. MATERIALS AND METHODSStudy area -The study area was situated in the localities of Santa Rosa, Colonia Tabay and Colonia Tata Cuá of the Department of Concepción, Corrientes, Argentina (27º to 28ºS and 57º to 58ºW). Biogeographically the area belongs to the oriental district of the Chaco region (Cabrera & Willink 1973).Socioeconomic characteristics -Most of the houses were built with materials obtained from the environment. Wood walls and sheet metal or cardboard roofs were observed in 62.5% of the households, the remainder had mud stick walls and thatched roofs. Similar materials were used to built the storerooms and kitchens.Domestic animals were present in 97% of the households, of which 80.5% were dogs, 55% cats and 53% hens.Peridomestic ecotopes were open structures made with sticks or wood, partially covered or not by a roof, 5-20 m far from the domiciles.The main act...

In order to identify intra- and extra-domiciliary triatomines, a study in different counties of Corrientes Province, Argentina, was conducted from 1985 to 1995. Triatoma infestans (Klug, 1834), Triatoma sordida (Stål, 1859), Panstrongylus geniculatus (Latreille, 1811), and Panstrongylus megistus (Burmeister, 1835) were detected in domestic ecotopes. T. infestans and T. sordida were also found in the peridomicile. Triatoma platensis (Neiva, 1913), Psammolestes coreodes (Bergroth, 1911), T. sordida, and Triatoma rubrovaria (Blanchard, 1843) were collected in sylvatic biotopes. T. infestans was confirmed as the predominant species in the domestic environment and was the only species infected with Trypanosoma cruzi-like parasites. T. sordida was most frequent in extra-domiciliary ecotopes, but could be considered capable of colonizing human dwellings.