Influence of Climatic Factors On Psorophora (Janthinosoma) Albigenu In Pantanal Landscape, Mato Grosso State, Brazil.

In order to assess the influence of climatic variations in temperature, relative humidity, and rainfall upon the population density of Psorophora albigenu (Peryassú, 1908) in its natural habitat, samplings were carried out at different times of the year in Mato Grosso, Brazil. Mosquitoes were captured with the use of suction tubes and Shannon traps during 2 different periods of the day and 1 at night. A total of 2,637 Ps. albigenu specimens were captured, including 497 (18.8%) in March 2009, 1,240 (47.0%) in January 2010, and 484 (18.4%) in January 2011. These months represented 84.2% of this species occurrence during the collection period. November was the month of the lowest occurrence of the species, with only 10 (0.4%) specimens collected in 2009 and 8 (0.3%) specimens in 2010. The climatological variable that presented a linear correlation coefficient within the 95% confidence interval was rainfall, with a linear correlation indicator of 0.793, above the relevance factor of 0.708, showing a relationship between the frequency of Ps. albigenu and rainfall of the region.

Ultrastructure and morphometry of the egg of Psorophora albigenu Lutz, 1908 (Diptera: Culicidae).

Eggs of Psorophora albigenu were analyzed by light and scanning electron microscopy. Eggs were laid singly and were black and elliptical in outline. A length of approximately 586.4 ± 10.83 µm, a width of 172.3 ± 8.09 µm (n=30), and an egg index (length/width ratio) of 3.33 were observed. The anterior extremity tapered abruptly from a width of 64.9 µm, while such tapering was more gradual at the posterior extremity from a width of 77.4 µm. The ventral surface of the chorionic coating presented cells with tubular aspect containing tubercles in rows with a density of 9-16 tubercles per cell. These tubercles presented two different sizes, with the largest measuring 7.87 ± 01.58 µm and the smallest measuring 0.71 ± 0.53 µm (n=30) in longitudinal diameter. The micropyle orifice was very evident, with a diameter of 3.36 µm. The morphometric characteristics of Ps. albigenu obtained in this study were distinct from those of other species of the Psorophora genus, including Psorophora varipes which has been considered for a long time to be synonymous with Ps. albigenu.

New report on the bionomics of Coquillettidia venezuelensis in temporary breeding sites (Diptera: Culicidae).

INTRODUCTION: Findings of immature forms of Coquillettidia venezuelensis in temporary breeding sites, without the presence of aquatic plants or other submerged plant tissue are reported. METHODS: A systematic scooping technique to collect specimens was used at the breeding site. RESULTS: Immature forms of Coquillettidia venezuelensis, Anopheles rangeli, An. evansae and Culex sp. were collected from areas of the hydroelectric power station of São Salvador, State of Goiás. CONCLUSIONS This is a novel finding relating to the bioecology of Cq. venezuelensis, a species of medical interest that has been found naturally infected with arboviruses, including Oropouche and West Nile virus.

New report on the bionomics of Coquillettidia venezuelensis in temporary breeding sites (Diptera: Culicidae) / Novo relato sobre a bionomia de Coquillettidia venezuelensis em criadouros temporários (Diptera: Culicidae)

INTRODUCTION: Findings of immature forms of Coquillettidia venezuelensis in temporary breeding sites, without the presence of aquatic plants or other submerged plant tissue are reported. METHODS: A systematic scooping technique to collect specimens was used at the breeding site. RESULTS: Immature forms of Coquillettidia venezuelensis, Anopheles rangeli, An. evansae and Culex sp. were collected from areas of the hydroelectric power station of São Salvador, State of Goiás. CONCLUSIONS This is a novel finding relating to the bioecology of Cq. venezuelensis, a species of medical interest that has been found naturally infected with arboviruses, including Oropouche and West Nile virus.

INTRODUÇÃO: Relata-se o encontro de formas imaturas de Coquillettidia venezuelensis em criadouros temporários, sem presença de plantas aquáticas ou outros tecidos vegetais submersos. MÉTODOS: Realizaram-se coletas com a técnica de conchadas sistemáticas na margem do criadouro. RESULTADOS: Foram coletados imaturos de Coquillettidia venezuelensis, Anopheles rangeli, An. evansae e Culex sp., em áreas da Usina Hidrelétrica de São Salvador, Estado de Goiás. CONCLUSÕES: Trata-se de observação inédita sobre a bioecologia de Cq. venezuelensis, espécie de interesse médico, que tem sido encontrada naturalmente infectada com arbovírus, inclusive Oropouche e West Nile.

Immature mosquitoes of Serra do Mar park, Sao Paulo State, Brazil.

With the objective of providing knowledge about the natural habitat of mosquito larvae, we conducted a study on the culicid fauna and identified larval habitat types at 3 different locations in the Serra do Mar State Park, Brazil, over the 12 months of 1991. We collected 1,425 larvae belonging to 23 species, of which the most frequent were Culex iridescens, Culex spp., Limatus durhami, and Trichoprosopon pallidiventer. The mosquito larval habitats presenting the greatest densities of specimens were bamboo, bromeliads, rubber boots, and streams. We observed that the culicids used a variety of containers as larval habitats and bred under a diversity of ecological conditions. Most of the habitats were natural, formed by bamboo, bromeliads, streams, and depressions in the ground and in rocks, along with artificial habitats consisting of rubber boots and abandoned metal cans. Seven species occurred preferentially in the internodes of closed bamboo stems, 6 in internodes of open stems, and 4 in bromeliads.

Biodiversity and influence of climatic factors on mosquitoes (Diptera: Culicidae) around the Peixe Angical hydroelectric scheme in the state of Tocantins, Brazil.

The influence of climatic factors on the seasonal frequency of mosquitoes (Diptera: Culicidae) at the Peixe Angical hydroelectric scheme (Tocantins, Brazil) was evaluated in the present paper. Mosquito surveys were conducted in the municipality of Peixe and in areas surrounding the reservoir in the municipalities of Paranã and São Salvador do Tocantins during two daytime periods (10 am-12 noon and 2 pm-4 pm) and two night-time periods (6 pm-8 pm and 6 pm-10 am) over 14 months. In total, 10,840 specimens from 42 species were captured, 84.5% of which belonged to the Culcinae. The most common species were Anopheles darlingi, Psorophora albipes and Sabethes chloropterus. The number of Culicidae specimens was higher in months with higher rainfall and air humidity than during the drier months. The large population of Ps. albipes and the presence of both An. darlingi (primary vector for human malaria parasites) and Haemagogus janthinomys (primary vector for yellow fever virus) are highlighted.

Biodiversity and influence of climatic factors on mosquitoes (Diptera: Culicidae) around the Peixe Angical hydroelectric scheme in the state of Tocantins, Brazil

The influence of climatic factors on the seasonal frequency of mosquitoes (Diptera: Culicidae) at the Peixe Angical hydroelectric scheme (Tocantins, Brazil) was evaluated in the present paper. Mosquito surveys were conducted in the municipality of Peixe and in areas surrounding the reservoir in the municipalities of Paranã and São Salvador do Tocantins during two daytime periods (10 am-12 noon and 2 pm-4 pm) and two night-time periods (6 pm-8 pm and 6 pm-10 am) over 14 months. In total, 10,840 specimens from 42 species were captured, 84.5 percent of which belonged to the Culcinae. The most common species were Anopheles darlingi, Psorophora albipes and Sabethes chloropterus. The number of Culicidae specimens was higher in months with higher rainfall and air humidity than during the drier months. The large population of Ps. albipes and the presence of both An. darlingi (primary vector for human malaria parasites) and Haemagogus janthinomys (primary vector for yellow fever virus) are highlighted.

Feeding patterns of Haemagogus capricornii and Haemagogus leucocelaenus (Diptera: Culicidae) in two Brazilian states (Rio de Janeiro and Goiás).

We present the identification of bloodfeeding sources of Haemagogus (Haemagogus) capricornii Lutz and Haemagogus (Conopostegus) leucocelaenus (Dyar & Shannon) (Diptera: Culicidae) from different regions of Brazil, as analyzed by precipitin tests. Anti-sera for bird, bovine, equine, human, opossum, and rodent were used. Two hundred one mosquitoes were examined (147 Hg. leucocelaenus and 54 Hg. capricornii), of which 177 reacted for some anti-serum. For Hg. leucocelaenus, 86 (68.3%) reacted to one blood source, 38 (30.2%) to two sources, and two (1.6%) to three sources; the combinations of bird + human (18.4%), bird + rodent (15.8%), and bird + marsupial (15.8%) were the most frequent. For Hg. capricornii, 34 (66.7%) reacted to one blood source; combinations bird + rodent (37.5%) and bird + marsupial (25%) were the most frequent combinations. Mosquito preference for bloodfeeding sources was different in these areas, possibly because of the availability of sources. This diversity of sources can have important epidemiological implications.

Aspectos da ecologia de mosquitos (Diptera: Culicidae), Vetores potenciais de doenças humanas, em áreas do Aproveitamento Hidrelétrico Peixe Angical, Estado do Tocantins, Brasil / Aspects of mosquitoes (Diptera: Culicidae) ecology, potential Vectors of human diseases, in areas of the Aproveitamento Hidreletrico Peixe Angical, State of Tocantins, Brazil

No presente estudo objetivamos avaliar a dinâmica populacional das espécies de mosquitos (Diptera: Culicidae) em relação ao impacto ambiental causado pela construção do Aproveitamento Hidrelétrico Peixe Angical, Estado do Tocantins, Brasil. As amostragens foram realizadas no município de Peixe e áreas circunvizinhas ao reservatório nos municípios de Paranã e São Salvador, em dois períodos diurnos e um noturno, onde componentes da equipe do Laboratório de Diptera, com tubos de sucção oral capturaram os mosquitos pousados na vegetação circunvizinha ou eventualmente por eles atraídos. Foram realizadas amostragens em armadilhas do tipo Shannon e CDC. Foram capturadas 40 espécies totalizando 12.968 espécimes, dos quais 61,85por cento pertencentes à subfamília Culicinae. O município de Peixe foi o de maior prevalência para anofelinos, Paranã para os sabetíneos, enquanto que os culicíneos demonstraram certo ecletismo em relação a preferência por pontos de captura. No período anterior à formação do reservatório, os meses de maior precipitação pluviométrica se mostraram os mais favoráveis para incidência dos culicídeos, enquanto que os meses mais secos registraram as menores ocorrências. A construção do AHE Peixe Angical e a conseqüente formação do reservatório exerceram forte influência na incidência dos anofelinos. A importância epidemiológica de espécies de culicídeos como: An. darlingi, An. albitarsis, e Hg. janthinomys, presentes e diretamente relacionadas ao AHE Peixe Angical, indicam fortemente que seja realizado o monitoramento das populações desses vetores em áreas sob intensa intervenção do homem, especialmente em empreendimentos hidrelétricos semelhantes.

Feeding patterns of Haemagogus janthinomys (Diptera: Culicidae) in different regions of Brazil.

New data on the feeding patterns of Haemagogus (Haemagogus) janthinomys Dyar from different geographical regions of Brazil, by using the precipitin test as the bloodmeal-identifying tool, are presented. The following antisera were used: bird, dog, human, rodent, cattle, horse, and opossum. The origins of 287 bloodmeals were identified, whereas 33 specimens were negative to the antiserums tested. Among the reactive specimens, 174 (60.6%) fed on only one food source, of which 35.1% originated from birds, 19.5% from rodents, 12.6% from humans, 10.3% from cattle, 10.3% from opossums, 7.5% from dogs, and 4.6% from horses. One hundred six (37.0%) mosquitoes fed on two sources, of which the most common combinations were bird + rodent (16.0%), bird + human (10.4%), and horse + human (9.4%). Seven (2.4%) mosquitoes fed on three different hosts. Our results suggest that Hg. janthinomys is more eclectic and opportunist than previously known in relation to its hosts and that such patterns are probably highly adaptive to a temporally and spatially variable environment.