Response of Triatoma infestans to pour-on cypermethrin applied to chickens under laboratory conditions

This article reports the effects of a pour-on formulation of cypermethrin (6% active ingredient) applied to chickens exposed to Triatoma infestans, the main vector of Chagas disease in rural houses of the Gran Chaco Region of South America. This study was designed as a completely random experiment with three experimental groups and five replicates. Third instar nymphs were fed on chickens treated with 0, 1 and 2 cc of the formulation. Nymphs were allowed to feed on the chickens at different time intervals after the insecticide application. Third-instar nymphs fed on treated chickens showed a higher mortality, took less blood during feeding and had a lower moulting rate. The mortality rate was highest seven days after the insecticide solution application and blood intake was affected until 30 days after the application of the solution.

Wild Triatoma infestans, a potential threat that needs to be monitored

The current persistence of Triatoma infestans, and therefore of Chagas disease transmission, in the Andean valleys of Bolivia and the Gran Chaco (precisely where wild populations of the vector are widespread), indicates a possible relationship between these two occurrences. This paper provides an overview of the current knowledge regarding wild T. infestans in Bolivia. The different morphs of the wild vector, their known distributions and some traits of their biology and ecology are presented. Particularly interesting is the considerable behavioural and chromatic plasticity that is displayed by wild T. infestans. According to the biogeographic region, different morphs of the vector occur in rupicolous habitats (common form and Mataral morph in Andean wild T. infestans) or arboreal ones ("dark morph" populations from the Chaco). The high genetic variability found at the microgeographical scale in Andean wild T. infestans favours the hypothesis that the Andes were the centre of origin and dispersal of T. infestans throughout South America. The relevant question regarding the origin of domestic populations is also addressed. Finally, current considerations of the epidemiological significance of wild T. infestans are discussed in the context of recent discoveries. Even if several observations support the epidemiological risk represented by wild T. infestans, the climatic and environmental conditions of their distribution areas would not favour the continued flow of triatomines between sylvatic refuges and domestic environments.

The residual efficacy of a cypermethrin pour-on formulation applied on goats on the mortality and blood intake of Triatoma infestans

Triatoma infestans is the main vector of Trypanosoma cruzi, the aetiological agent of Chagas disease in the Gran Chaco region of South America. As a frequent blood meal source for triatomine bugs, domestic goats play a key role in the eco-epidemiology of Chagas disease. The aim of this study was to evaluate the mortality and blood intake of T. infestans fed on goats that had been treated with different doses of pour-on insecticide. Third-instar nymphs were fed on goats that had been treated with 0 cc, 5 cc, 10 cc or 15 cc of a pour-on formulation of cypermethrin. The exposure of T. infestans to animals treated at different post-application intervals revealed a residual activity of the insecticide. The mortality rate in the treated groups was higher than in the control groups until 30 days post-insecticide application (p = 0.03), except in the group treated with 5 cc, in which no mortality was detected after seven days of insecticide application. Rainfall affected the triatomicide effect, reducing the time of residual activity. The cypermethrin pour-on treatment decreased the blood intake of T. infestans. Thirty days after the cypermethrin application, nymph mortality was 16% (± 13) with both doses (10 cc and 15 cc). The 15 cc dose did not result in higher insect mortality or increased persistence compared to the 10 cc dose.

O gênero Callideriphus Blanchard, 1851 (Coleoptera, Cerambycidae, Heteropsini)

The genus Callideriphus Blanchard, 1851 (Coleoptera, Cerambycidae, Heteropsini). The genus Callideriphus comprises only two species: C. grossipes Blanchard, 1851 (type species) and C. tucumanus sp. nov. (Argentina, Tucumán). The type locality of C. grossipes had been originally indicated as Chile, but it is supposedly considered erroneous. Its distribution, actually, extends from Southeastern Brazil up to Argentina, along the Atlantic Forest. This species is extremely variable in regard to its coloration and elytral punctation. Two subspecies are recognized: C. grossipes grossipes Blanchard, 1851 (BRAZIL: Minas Gerais, Espírito Santo, São Paulo, Paraná, Santa Catarina) and C. grossipes flavipennis Melzer, 1934 (BRAZIL: Santa Catarina, Rio Grande do Sul; ARGENTINA: Chaco, Entre Ríos, Buenos Aires). Four intermediate forms are recorded and commented. Redescription and a key to species are added. Nomenclatural changes: Callideriphus grossipes grossipes Blanchard, 1851 = C. grossipes var. brasliensis Melzer, 1923 syn. nov. = C. rubricollis Melzer, 1934 syn. nov.; Callideriphus grossipes flavipennis Melzer, 1934 stat nov. = C. signaticollis Melzer, 1934 syn. nov.

Análise de parcimônia de endemismo de cercopídeos neotropicais (Hemiptera, Cercopidae)

The spittlebugs have an extent distribution in the American continent. Their diversity may determinate endemism areas based on their occurence in different localities. We have used Parsimony Analysis of Endemicity method, which is an important historic biogeography tool for detecting and establishing the relationship among endemics areas. A data matrix was built up based on the occurence registration for the species by 66 genus in whole localities divided in five degrees quadrats in the Neotropical Region, using 49 OGUs (Operative Geografic Units). The presence of the taxa in the areas was coded 1 and the absence 0. The data matrix was analysed based on parsimony analysis through the computer program Hennig 86. Nine endemic areas were stipulated (Mexico + Central America, Venezuelan Savana, Guiana + Suriname, Chaco, Trans-andean, Cerrado, Amazon, Pampa and Atlantic Forest) in the first analysis corroborated with ecological and physiographic patterns in each region. The second analysis was made using 48 genera to obtain the relationship among the nine areas stipulated before. In this analysis just one cladogram (3((1,2)((8,9)(6(7(4,5)))))) was obtained with 192 steps, consistence index 0.80 and retention index 0.85.

Melostelis gen. nov., espécies novas e notas complementares sobre Anthidiini (Hymenoptera, Apidae)

Melostelis gen. nov., espécies novas e notas complementares sobre Anthidiini (Hymenoptera, Apidae). Melostelis gen. nov. é proposto para um novo Anthidiini cleptoparasita. São descritas e ilustradas duas espécies novas: Melostelis amazonensis sp. nov. de Manaus, Amazonas e Larocanthidium chacoense sp. nov. de Porto Murtinho, Mato Grosso do Sul. São dados a conhecer os machos de Epanthidium bolivianum Urban, 1995 e Epanthidium araranguense Urban, 2006 e, registrados pela primeira vez no Brasil, na sub-região do chaco, Ketianthidium zanolae Urban, 2000 e Epanthidium bolivianum.

A new species of Stilobezzia Kieffer from the neotropical region (Diptera, Ceratopogonidae)

A new species from the Neotropical Region, Stilobezzia (Stilobezzia) pseudopunctulata Cazorla & Ronderos, is described and illustrated based on male and female adults and pupal exuviae. Adults were collected in the Argentinian provinces of Chaco, Formosa, Corrientes and Buenos Aires, and in Santa Cruz, Bolivia. The pupa was collected from mats of floating aquatic macrophytes in a lagoon in Ilha da Marchantería, in the vicinities of Manaus, Brazil. This new species is compared with its similar congener Stilobezzia punctulata Lane, from which it can be mainly distinguished by the wing with only two dark spots, the parameres longer and hook-shaped, the pupal respiratory organ with 11-12 pores and the very short apicolateral processes of the anal segment.

Exserohilum rostratum patógeno de Caryota mitis en Argentina

Caryota mitis Loureiro (Arecaceae), es cultivada en Argentina como planta ornamental con fines comerciales. En el año 2003, muestras procedentes de la localidad de Castelli, provincia del Chaco, Argentina, presentaban atizonamiento de los ápices de las hojas, deteriorándolas considerablemente. Mediante métodos comunes de laboratorio se aisló un hongo Dematiaceae relacionado con los síntomas observados. Con base en las características culturales, morfométricas, pruebas de patogenicidad con resultados positivos, el agente causal fue identificado como Exserohilum rostratum (Drechsler) Leonard & Suggs. Esta es la primera información de E. rostratum afectando a C. mitis en Argentina.

Fitossociologia de remanescentes de floresta estacional decidual em Corumbá, Estado do Mato Grosso do Sul, Brasil

O estudo foi realizado em quatro remanescentes próximos a cidade de Corumbá, MS (19º05'-19º20' S e 57º40'-57º55' W), com o objetivo de verificar a variação da composição florística e estrutura da floresta decídua em diferentes relevos e tipos de solo. Quatro remanescentes foram amostrados pelo método de quadrantes. Três áreas foram amostradas com 20 pontos, e a quarta área foi amostrada com 50 pontos. Todas as árvores com circunferência à altura do peito > 9 cm foram amostradas. Na floresta estacional decidual aluvial foram amostradas 32 espécies, sendo as de maior valor de importância Attalea phalerata Mart. ex Spreng. (Arecaceae) e Aspidosperma australe Müll. Arg. (Apocynaceae). Nas duas áreas de floresta estacional decidual de terras baixas, foram amostradas 47 e 25 espécies, respectivamente, sendo Sebastiania discolor (Spreng.) Müll. Arg. (Euphorbiaceae) e Phyllostylon rhamnoides (J. Poiss.) Taub. (Ulmaceae) as mais importantes em ambas. No remanescente de floresta estacional decidual submontana foram amostradas 24 espécies, sobressaindo-se Acosmium cardenasii H.S. Irwin & Arroyo (Fabaceae) como a mais importante. A família mais rica nas áreas estudadas foi Fabaceae, com 16 espécies, seguida por Euphorbiaceae, com seis espécies, e por Apocynaceae, Rubiaceae e Sapindaceae, com três espécies cada. As duas áreas de florestas de terras baixas mostraram-se muito similares, tanto na composição florística, como na estrutura. A floresta aluvial apresentou composição florística e estrutura mais distintas das demais áreas. Estes remanescentes de florestas estacionais deciduais apresentaram estrutura e composição florística peculiares, com elementos do chaco e da caatinga, merecendo a intensificação de estudos botânicos e ecológicos.

Nutritional value and fatty acid composition of some traditional Argentinean meat sausages

The aim of this study was to determine the nutritional composition (moisture, protein, carbohydrates, and total fat) of some meat products produced in the northeastern Argentina, analyzing fatty acids composition, polyunsaturated/saturated fatty acid ratio PUFA/SFA ratio (polyunsaturated/ saturated fatty acids), n-6/n-3 ratio, and CLA (conjugated linoleic acid) content. Thirty traditional meat products produced by different processes were used. The samples were classified into 4 different categories as follows: salamín (dry cured and fermented sausage), chorizos (raw sausage), chorizo ahumado (cooked and smoked sausage), and morcilla (cooked sausage). From the results obtained it can be said that the total carbohydrate contents of the salamín studied were slightly lower; fat content of raw chorizo was significantly lower, and protein content of chorizo ahumado was significantly higher than those comparison from databases from other regions of Argentina, USA, and Spain. Except for chorizo, which has a value lower than 0.4, the PUFA/SFA-stearic ratio of the other products were a little higher than those reported by other researchers. CLA (Conjugated linoleic acid) contents between 0.03% and 0.19% were detected. The results obtained indicate that salamín produced in northeastern Argentina, Chaco state, shows high protein and PUFA (Polyunsaturated fatty acids) contents, and low atherogenic and thrombogenic indexes, which makes it a more healthful product than those of similar composition produced in other countries.

Efectos de la temperatura, el ambiente lumínico y la escarificación sobre la germinación de semillas de Bromelia serra Griseb. (Bromeliaceae)

Bromelia serra Griseb. (Bromeliaceae) es una hierba terrestre que habita en el sotobosque de bosques abiertos del Chaco y el Cerrado. En este trabajo se analizó el efecto de la temperatura, el clima lumínico y la escarificación sobre la germinación de semillas. Se evaluaron dos regímenes de temperatura (15/20 ºC y 20/30 ºC), tres ambientes lumínicos (Luz, Filtro y Oscuridad; 100% luz y 0.65 R:FR, 100% luz y 0.09 R:FR y sin luz respectivamente) y dos tratamientos de escarificación (Escarificación durante 1 min. con H2SO4 al 30% y Control sin escarificar). La temperatura fue un factor clave ya que solo se registró germinación (una reducida fracción de las semillas y en forma lenta) en el tratamiento a 20/30 ºC. Las semillas fueron indiferentes a la intensidad de luz, germinando tanto en condiciones de luz como de oscuridad. La calidad de la luz afectó la germinación, registrándose mayores porcentajes de germinación a altas relaciones R:FR. No se detectaron efectos de la escarificación en la germinación de las semillas. Los resultados de este trabajo aportan información básica sobre la germinación de semillas, que resultan útiles para el manejo de la especie.