Searches for Chagas disease vectors were performed at the type locality from which Triatoma sherlocki Papa et al. (Hemiptera: Reduviidae: Triatominae) was described in the municipality of Gentio do Ouro, in the state of Bahia, Brazil, and in a small artisan quarry-mining community approximately 13 km distant in a remote area of the same municipality. The latter site represents a new locality record for this species. Adults, nymphs and exuviae of T. sherlocki were found in 21% of human dwellings, indicating that the species is in the process of domiciliation. Prevalence of Trypanosoma cruzi infection in collected bugs was 10.8%. Simple predictive approaches based on environmental similarity were used to identify additional sites likely suitable for this species. The approach successfully predicted an additional five sites for the species in surrounding landscapes. Ecological and entomological indicators were combined to discuss whether this scenario likely represents an isolated case or an emerging public health problem.
"Triatoma brasiliensis species complex" was defined as a monophyletic group of the species: T. brasiliensis, T. juazeirensis, T. melanica, and T. sherlocki. An alternative grouping scheme proposed the concept of "Brasiliensis subcomplex" which included the former species together with T. melanocephala, T. petrocchiae, T. lenti, T. tibiamaculata, and T. vitticeps. To evaluate the relationship among these taxa we combined the results obtained with four mitochondrial genes (12S, 16S, COI and Cytb, adding to 1811bp) and geometric morphometric analysis of wings and heads. Panstrongylus megistus was included in the analysis as it was previously found related to T. tibiamaculata, T. melanocephala and T. vitticeps. The results of both molecular and morphometric approaches clearly grouped the species analyzed into two monophyletic units, supported by both genetic and wing variability. The first one (G1) comprises the four species originally included in the T. brasiliensis species complex plus T. lenti and T. petrocchiae. The second group (G2) was composed by T. melanocephala, T. tibiamaculata and T. vitticeps, and remarkably, P. megistus if considering wing variability and phylogenetic results. Nevertheless, geometric morphometrics of heads provided a quantitative measurement that discriminates Panstrongylus from the Triatoma species based on the position of the antennal insertion relative to eyes, as it is used as the generic distinctive character. The discrepancy among approaches questions the validity of this character to define Panstrongylus genus. Independently of the chosen group definition -"T. brasiliensis species complex" or "Brasiliensis subcomplex"-we propose to delimit it to species of G1 that are all associated with the Caatinga biome in the Brazilian Northeast. G2 are the ones associated with the Atlantic Forest biome.
-The effects of environmental factors on the richness, diversity and abundance of ants were studied in the Restinga da Marambaia, south coast of Rio de Janeiro State, Brazil. The samples were taken using pitfall traps in August/2004 (winter) and March/2005 (summer) in three different vegetation types: (1) herbaceous ridge palmoid (homogeneous habitat); (2) shrub dune thicket and (3) ridge forest (heterogeneous habitats). At each habitat a range of environmental attributes was recorded: soil temperature and humidity, percentage of soil covering by litter and litter depth. Ninety-two ant species belonging to 36 genera and eight subfamilies were recorded. Density of ant species and abundance varied signifi cantly between habitats and seasons; ant diversity varied only between habitats. Homogeneous habitat had lower ant species density, abundance and diversity than heterogeneous habitats. The two fi rst variables were positively correlated with litter depth and both were higher in summer than in winter samples. There were more species of Ponerinae and Ectatomminae in heterogeneous than in the homogeneous habitat, whereas the Formicinae species were more abundant in the later.KEY WORDS: Formicidae, ground-dwelling ant, Neotropical fauna, plant physiognomy RESUMO -A infl uência de fatores ambientais sobre a diversidade, riqueza e abundância de formigas em comunidade de restinga foi avaliada na Marambaia, litoral sul do estado do Rio de Janeiro. As amostras foram tomadas em agosto de 2004 (inverno) e março de 2005 (verão) em três fi sionomias vegetais: (1) vegetação herbácea fechada de cordão arenoso (habitat homogeneo), (2) arbustiva fechada de cordão arenoso e (3) fl oresta de cordão arenoso (habitats heterogeneos). Em cada formação foram medidos os seguintes atributos ambientais: temperatura e umidade do solo, cobertura do solo por serapilheira e profundidade da serapilheira. Noventa e duas espécies distribuídas em 36 gêneros e oito subfamílias foram coletadas. A densidade de espécies e a abundância variaram signifi cativamente com a fi sionomia e época de coleta; a diversidade apenas com a fi sionomia. O habitat homogêneo teve menor densidade de espécies, abundância e diversidade do que os habitats heterogêneos. As duas primeiras variáveis foram positivamente correlacionadas com a profundidade da serapilheira e ambas foram maiores na amostragem de verão do que na de inverno. Houve mais espécies de Ponerinae e Ectatomminae nos ambientes mais heterogêneos, enquanto que Formicinae foi mais abundante no ambiente homogêneo.
Even though Chagas disease is rare in the Brazilian Amazon, the conditions for the establishment of domiciliated cycles prevail in many areas where triatomines are of frequent occurrence. In Roraima, a previous serological and entomological survey in three agricultural settlements showed the existence of all transmission cycle elements, i.e., individuals infected by Trypanosoma cruzi, triatomine species previously found harboring T. cruzi in the broader Amazon region of neighboring countries and, domicile/ peridomicile conditions favorable to triatomine colonization. Triatoma maculata was the most frequent species, found in chicken houses in the peridomicile and sporadically within residences. Aiming to investigate the possibility of T. maculata to possess the potentiality to transmit T. cruzi in the area, bionomic characteristics were studied under laboratory conditions. These were feeding frequency, time for defecation after a blood meal, time elapsed in voluntary fasting pre- and pos-ecdysis, moulting time periods, pre-oviposition and oviposition periods and index of oviposition, incubation period, egg viability, longevity and mortality rate. Results show that the Passarão population of T. maculata should be considered a potential vector of T. cruzi since it shows a capacity to infest artificial ecotopes in the peridomicile, to carry out large number of meals during the nymphal cycle, to have a relatively short developmental cycle capable of producing 2.9 generations/year, to blood source eclecticism, to defecate immediately after the blood meal while still on the host and to the fact that has been previously found naturally infected by T. cruzi.
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