Las arañas son ideales como indicadores de cambios ecológicos por su diversidad y abundancia. En la provincia de Corrientes, Argentina, se estudiaron arañas de Citrus sinensis en parcelas de 0.82 hectáreas, con riego (AM1) y sin riego (AM2). Mediante pitfall, agitación de follaje, captura manual y tamizado de hojarasca se recolectaron 7 174 ejemplares (33 familias, 44 géneros y 200 especies/morfoespecies), el 70% fueron juveniles. AM1 registró 3 811 individuos (33 familias, 179 especies/morfoespecies) y AM2 3 363 (31 familias, 174 especies/morfoespecies). Durante el verano se observó la mayor abundancia. En ambas parcelas, ocho familias representaron el 75% del total, Lycosidae fue la más numerosa y se identificaron ocho gremios; las vagabundas de suelo fueron las más abundantes (AM1 n=1341, s=39; AM2 n=999, s=33) seguida por las constructoras de telas orbiculares (AM1 n=637, s=36; AM2 n=552, s=33), las cazadoras al acecho (AM1 n=471, s=43; AM2 n=453, s=47) y las de telas espaciales (AM1 n=446, s=23; AM2 n=342, s=25. La diversidad alfa en ambas parcelas (AM1 H’=4.161, J’=0.802; AM2 H’=4.184, J’=0.811) no mostró diferencias significativas (t=1.083, p=0.279). El modelo de dependencia lineal fue el que mejor ajustó los resultados. El modelo de Clench estimó el 90.9% de las observadas en AM1 y el 90.6% en la AM2.

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 spe- cies/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 web- builders (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.

El proceso de urbanización representa una de las amenazas más importantes a la biodiversidad. Los lepidópteros son uno de los grupos taxonómicos utilizados como indicadores de la diversidad y calidad del ambiente. El objetivo del presente trabajo es conocer los Lepidoptera (Papilionoidea y Hesperioidea) de la ciudad de Corrientes. Se llevaron a cabo muestreos al azar en un parche de bosque nativo situado en el barrio Santa Catalina y en un área antropizada, el Parque Mitre. Las recolectas se realizaron en las cuatro estaciones climáticas entre enero y octubre de 2007 con redes entomológicas. El total de ejemplares capturados asciende a 1 114, los que se distribuyen en seis familias: Hesperiidae, Lycaenidae, Nymphalidae, Papilionidae, Pieridae y Riodinidae y 18 subfamilias. Se identificaron 59 géneros y 75 especies. Anartia jatrophae jatrophae fue la especie más abundante en ambas unidades. Esta especie junto a Urbanus procne, Phoebis sennae marcellina, Pyrgus orcus y Dryas iulia alcionea se capturaron en todas las estaciones. El mayor número de ejemplares se colectó en las estaciones más cálidas. La abundancia (n=701), riqueza (S=74) y diversidad (H’=3.87) fueron superiores en Santa Catalina. Las unidades exploradas exhiben una elevada riqueza de especies y alta similitud.

Diversity of the order Lepidoptera (Hesperioidea and Papilionoidea) from Corrientes city, Argentina. Urbanization is one of the most important threats for biodiversity. Among many different organisms, butterflies are useful indicators of environment diversity and quality. The aim of this study was to investigate the Lepidoptera from Corrientes city. Random samplings were performed at two sites: a native forest situated in Santa Catalina district and an urban area, Parque Mitre. The captures were carried out using entomological nets, at four seasons between January to October 2007. A total of 1 114 butterflies, represented by six families: Hesperiidae, Lycaenidae, Nymphalidae, Papilionidae, Pieridae and Riodinidae and 18 subfamilies were recorded. Fifty-nine genera and 75 species were identified; Anartia jatrophae jatrophae was the most abundant species at both localities. This species and Urbanus procne, Phoebis sennae marcellina, Pyrgus orcus and Dryas iulia alcionea were, among other seven, captured at all months. Highest values of abundance were registered during the warmest seasons. Santa Catalina presented the largest abundance (n=701), richness (S=74) and diversity (H’=3.87). A total of 413 individuals and 52 species were identified at Parque Mitre, and Shannon diversity index was 3.58. The obtained data reveals a high species richness and similarity at both sites. Rev. Biol. Trop. 59 (1): 299-308. Epub 2011 March 01.

The aim of this investigation was to evaluate triatomine colonization in domestic and extradomestic ecotopes, to determine triatomines infection index and to assess human prevalence of anti Trypanosoma cruzi antibodies at Berón de Astrada and Mburucuyá Departments, Corrientes, Argentina. Samplings were performed in 2007 and 2008 in randomly selected households at rural areas. Diagnosis of Chagas infection in volunteer residents was performed using indirect hemagglutination, indirect immunofluorescence and indirect immunoenzimatic assay. Thirty human dwellings and 25 peridomestic ecotopes were searched at Berón de Astrada, and 32 houses and 33 peridomiciles at Mburucuyá. A total of 19 nymphs were captured in a chicken coop at Mburucuyá, the infestation rate was 3.0%. At Berón de Astrada 4.0% of the peridomiciles resulted infested by Triatoma sordida, a female and 58 eggs were collected in a hen nest. Trypanosoma cruzi infection was not detected in Triatoma sordida. The prevalence human rate was 5.2% (11/77) at Mburucuyá and 14.3% (4/77) at Berón de Astrada. Presence of triatomines was not confirmed at the human dwellings, and the infestation of the peridomestic structures was low. It is necessary to implement new strategies of vectorial control, especially for those species that prevail in the peridomicile and sylvatic ecotopes. Seroprevalence was lower that the observed in previous investigations in other rural areas of Corrientes. The absence of seroreactives in the 0-10 age group suggests a halt in T. cruzi transmission in the studied area.

El objetivo de esta investigación fue evaluar la presencia de triatominos en ecotopos domésticos y extradomésticos, determinar el índice de infección de los triatominos y estimar la prevalencia humana de anticuerpos contra el Trypanosoma cruzi. Los muestreos se llevaron a cabo en viviendas seleccionadas al azar en áreas rurales (departamentos Mburucuyá en otoño 2007 y Berón de Astrada en verano 2008) de Corrientes, Argentina. El diagnóstico de la infección chagásica se realizó a voluntarios mediante las pruebas de hemaglutinación indirecta, inmunofluorescencia indirecta y ensayo inmunoenzimático. Se exploraron 32 viviendas y 33 peridomicilios en Mburucuyá, y 30 viviendas y 25 peridomicilios en Berón de Astrada. En Mburucuyá la infestación del peridomicilio por Triatoma sordida alcanzó un 3.0%, capturándose 19 ninfas en un gallinero. La infestación del peridomicilio en Berón de Astrada fue 4.0%, detectándose una hembra y 58 huevos en un nidal de ave. Tanto la hembra como las ninfas resultaron negativas al T. cruzi. La prevalencia de seropositivos humanos al T. cruzi fue 5.2% (4/77) en Mburucuyá y 14.3% (11/77) en Berón de Astrada. En el domicilio no se confirmó infestación por triatominos y en el peridomicilio el índice de infestación fue bajo. Es necesario implementar nuevas estrategias de control vectorial, especialmente para las especies que habitan en estructuras peridomésticas y biotopos silvestres. La seroprevalencia fue menor a la observada en investigaciones previas en las áreas rurales de Corrientes. La ausencia de seropositivos de 0-10 años indica que la transmisión vectorial está interrumpida.

El objetivo de este trabajo fue conocer la composición taxonómica, abundancia y diversidad de los Culicidae de la Reserva Provincial Iberá. La investigación se llevó a cabo en Estancia Rincón, Colonia Carlos Pellegrini y Paraje Galarza, provincia de Corrientes, Argentina. En el área de estudio los muestreos se realizaron en tres transectas de 200m de longitud y 2m de ancho en bosque y pastizal. Los ejemplares se capturaron en forma manual con aspiradores sobre cebo humano y trampa de luz.Se colectaron 1694 mosquitos pertenecientes a nueve géneros y 21 especies. En la unidad de paisaje correspondiente al bosque se observó mayor diversidad que en el pastizal. El 13,5% de los culícidos fue atraído por las trampas de luz y el 86,5% por cebo humano. Se capturaron especies importantes como vectoras de virus. La distribución, abundancia y composición específica de la culicidofauna fueron distintas en las localidades y unidades ambientales estudiadas. En Estancia Rincón la degradación del bosque producida por el ganado podría explicar el reducido número de especies. En Colonia Carlos Pellegrini y Paraje Galarza Aedes (Ochlerotatus) scapularis (Rondani, 1848) fue abundante, pero la presencia de numerosos ejemplares de Limatus durhami Theobald, 1901 y pocos individuos de las tribus Mansonini y Culicini indican una reducida influencia antrópica.

The object of this study was to analyze the taxonomic composition, abundance and diversity of Culicidae in the Iberá Province Reserve. The investigation was carried out in Estancia Rincón, Colonia Carlos Pellegrini and Paraje Galarza, Corrientes Province, Argentina. Samples were taken along three transects of 200m x 2m in forests and grasslands. Mosquitoes were captured with aspirators on human bait and with light traps. A total of 1694 mosquitoes was collected and 9 genera and 21 species were identified. Forest diversity was higher than in grasslands. Some 13.5% of the total mosquitoes fauna were attracted to light traps and 86.5% to human bait. Species of great importance as virus vectors were captured. The distribution, abundance and specific composition were different among localities and environmental unities. In Estancia Rincon the intensive forest degradation resulting from cattle raising might explain the lower species richness. Aedes (Ochlerotatus) scapularis (Rondani, 1848) was abundant in Colonia Carlos Pellegrini and Paraje Galarza, nevertheless the presence of Limatus durhamii Theobald, 1901 and the scarce number of Mansonini and Culicini tribe specimens indicates a low anthropic influence.

Se estudió la estructura poblacional de Triatoma sordida que infesta Butia yatay y su abundancia relativa durante un año, en Colonia Laurel, Departamento San Roque, Corrientes, Argentina (28° 28’ S; 58° 26’ W). Los muestreos se realizaron en primavera de 1998, verano, otoño e invierno de 1999. Se disecaron 55 ejemplares de palmas y se confirmó el predominio de T. sordida (N= 423) en relación al reducido número de Triatoma platensis y de Psammolestes coreodes capturados. Es la primera cita para Argentina sobre la presencia de T. sordida en esta especie de palma. La abundancia relativa de T. sordida mostró una marcada estacionalidad. En primavera el total de individuos colectados triplicó al hallado en las restantes estaciones y las abundancias relativas oscilaron entre 57 y 88 individuos por mes, coincidiendo con el período reproductivo de la especie. Todos los estadios ninfales estuvieron presentes, con predominio de NIII, NIV y NV. En forma global, las ninfas representaron el 91,7%, los huevos el 4,3% y los adultos el 4,0% de la población total colectada. La menor abundancia se verificó en Enero y podría interpretarse como una inhibición del desarrollo causado por las temperaturas elevadas. Algo semejante ocurrió en Junio, al registrarse la temperatura ambiental más baja, en invierno se produciría la mayor mortalidad de ninfas menores, conduciendo a la presencia de pocos ejemplares y aún a la extinción. Las fluctuaciones en la densidad de esta especie se atribuyen a factores bioclimáticos y a la disponibilidad de fuentes de alimentación.

The population structure of Triatoma sordida in the palm Butia yatay, and its relative abundance during 1 year was studied in Colonia Laurel, Departamento San Roque, Corrientes, Argentina (28° 28’ S; 58° 26’ W). Samples were collected in the spring of 1998 and the summer, autumn and winter of 1999. Fifty-five palms were examined, and the predominance of T. sordida (N = 423) was confirmed in relation to the reduced number of T. platensis and Psamolestes coreodes captured. It is the first citation in Argentina of the presence of T. sordida in this species of palm. The relative abundance of T. sordida shows a marked seasonality. In spring, the total of individuals collected tripled those found in the remaining seasons, and the relative abundance oscillated between 57 and 88 individuals per month, coinciding with the reproductive period of the species. All the nymphal stages were present, with a predominance of NIII, NIV and NV. Of the total population collected, nymphs represented 91.7%, eggs 4.3%, and adults 4.0%. The lowest abundance was reported in January and could be interpreted as an inhibition of development caused by elevated temperatures. Something similar occurred in June (winter), when the lowest environmental temperatures were recorded, producing the greatest mortality of small nymphs, resulting in the presence of few or no specimens. The fluctuations in the density of this species can be attributed to bioclimatic factors and the availability of blood meals sources.

An entomological and serological survey was performed in three localities of the Department of Concepción, Province of Corrientes, Argentina in 1998 and 1999, to identify triatomines species involved in domestic and wild transmission of Chagas disease. Triatomines were collected by man/hour capture in 32 houses randomly selected and 44 nearby outdoor ecotopes. Trypanosoma cruzi infection in triatomines was assessed by direct microscopic observation (400x) of feces and polymerase chain reaction. Serological techniques used for people were Indirect Hemagglutination Test and Indirect Fluorescent Test. Triatomines were collected in 28.1% of the houses and 31.8% of the wild biotopes. Triatoma infestans (Klug 1834) was exclusively found indoors and T. cruzi infected 60% of them. Triatoma sordida (Stål 1859) was mainly found in extradomestic ecotopes where trypanosome infection rate reached 12.7%. Serological study of 98 local people showed that 29.6% were seroreactive; most of their houses were closed to wild biotopes colonized by T. sordida. Results indicate that there is an active T. infestans mediated transmission of Chagas disease in this zone that yields important human prevalence and that the populations of T. sordida in wild biotopes not only sustain the wild T. cruzi cycle but also represent an actual risk for people living in the area.

Several palms species provide an important habitat for triatomines and associate vertebrates in tropical America. The objective of this work is to identify the triatomine species living in the palms of rural areas in the Province of Corrientes, and to estimate the potential epidemiological risk they represent for the residents of nearby houses. The survey was carried out in a palm community in Colonia Laurel, Department San Roque, Province of Corrientes, Argentina. Samplings were performed in October, November and December 1998; January, February and March 1999; May and June 1999. Thirty palms: 27 (90%) Butia yatay (Mart.) Becc. and 3 Acrocomia aculeata (Jacq.) Lodd ex Mart. were dissected. Triatoma sordida Stål 1859 was found in 96.2% of B. yatay and in all the A. aculeata palms. A total of 272 live T. sordida was collected; 36 of them (13.2%) were found in bird nests in the frond and the remainder in other locations of the tree. The mean number of triatomines per palm was 9.6 (range 1-60, mode 2). T. sordida was collected during all the sampling months and all stages were present at all seasons. The highest population density was reached in spring and the lowest in autumn. Trypanosoma cruzi was detected in 38.5% in feces of 174 examined insects and identified as such, both by microscopical examination and PCR. This is the first finding of T. sordida populations in B. yatay, an endemic palm of South America distributed in southern Brazil, Uruguay and northeastern Argentina. The high infection prevalence found in this work suggests that T. sordida plays an essential role in the maintenance of the wild T. cruzi transmission cycle in northeastern Argentina.

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.

Esta investigación tiene como objetivo identificar los triatominos que predominan en ambientes domésticos y extradomésticos de diferentes departamentos de la Provincia de Corrientes mediante muestreos llevados a cabo desde 1985 hasta 1995. En los ecótopos domiciliarios se detectaron Triatoma infestans (Klug, 1834), Triatoma sordida (Stål, 1859), Panstrongylus geniculatus (Latreille, 1811) y Panstrongylus megistus (Burmeister, 1835). T. infestans y T. sordida se hallaron también en ambientes peridomésticos. Triatoma platensis (Neiva, 1913), Psammolestes coreodes (Bergroth, 1911), T. sordida y Triatoma rubrovaria (Blanchard, 1843) se colectaron en biótopos silvestres. En los domicilios, se confirmó el predominio de T. infestans. Esta especie fue la única parasitada por tripanosomas cruziformes. Si bien T. sordida fue más frecuente en los ecótopos extradomésticos, se demostró su tendencia a colonizar los ambientes domésticos.

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.

Esta investigación tiene como objetivo identificar los triatominos que predominan en ambientes domésticos y extradomésticos de diferentes departamentos de la Provincia de Corrientes mediante muestreos llevados a cabo desde 1985 hasta 1995. En los ecótopos domiciliarios se detectaron Triatoma infestans (Klug, 1834), Triatoma sordida (Stål, 1859), Panstrongylus geniculatus (Latreille, 1811) y Panstrongylus megistus (Burmeister, 1835). T. infestans y T. sordida se hallaron también en ambientes peridomésticos. Triatoma platensis (Neiva, 1913), Psammolestes coreodes (Bergroth, 1911), T. sordida y Triatoma rubrovaria (Blanchard, 1843) se colectaron en biótopos silvestres. En los domicilios, se confirmó el predominio de T. infestans. Esta especie fue la única parasitada por tripanosomas cruziformes. Si bien T. sordida fue más frecuente en los ecótopos extradomésticos, se demostró su tendencia a colonizar los ambientes domésticos.

The main goal was to know the epidemiologic, clinical, electrocardiographic and radiologic characteristics among a population of seropositives and seronegatives to Trypanosoma cruzi in a rural area of the Departament of San Miguel, province of Corrientes, Argentina. One hundred and thirty-two patients of different ages: 2-79 years old were researched (58 males, 74 females). In order to make a thorough assessment clinical evaluation and cardiologic testing were carried out. Signs and symptoms consistent with heart disease, blood pressure, 12-lead ECG registry and chest x-ray (PA view) were registered. In signs and symptoms, abnormal ECG patterns and radiologic abnormalities, non-significant statistic difference were observed. Although we were unable to find a significant relationship between chagasic infection and a higher prevalence for heart disease, it is important to stress the fact that 54.0% of the studied population was largely composed of very young patients whose ages were less than 20 years old, and 45.0% of those older than 41 years showed ECG abnormalities.

Esta investigación tiene por objeto analizar las características epidemiológicas, clínicas, electrocardiográficas y radiológicas de una población de seropositivos y seronegativos al Trypanosoma cruzi en una área rural del Departamento San Miguel, provincia de Corrientes, Argentina. Se seleccionaron 132 pobladores (58 hombres y 74 mujeres) de todos los grupos etareos para la realización de un examen clínico y cardiovascular. Se registraron síntomas y signos compatibles con afección cardíaca, tensión arterial, electrocardiograma de 12 derivaciones y radiografía anteroposterior de tórax. En la signo-sintomatología, anomalías electrocardiográficas y en las alteraciones radiográficas detectadas, no se observaron diferencias estadísticamente significativas entre seropositivos y seronegativos. Se concluye que si bien en la población objeto de estudio la infección chagásica no se asoció a mayor prevalencia de cardiopatía, cabe destacar que los pacientes chagásicos pertenecían a un grupo etareo muy joven con un 54,0% de ellos menores de 20 años y que el 45,0% de los pacientes mayores de 41 años tenían alteraciones electrocardiográficas.