Juliana Barreto Pacheco

Feeding Patterns of Haemagogus janthinomys (Diptera: Culicidae) in Different Regions of Brazil

Abstract 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.

Feeding Patterns of Haemagogus capricornii and Haemagogus leucocelaenus (Diptera: Culicidae) in Two Brazilian States (Rio de Janeiro and Goias)

Abstract 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.

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.

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

Abstract 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.

Circadian and seasonal preferences for hematophagy among Haemagogus capricornii, Hg. janthinomys, and Hg. leucocelaenus (Diptera: Culicidae) in different regions of Brazil.

Since the 1980s, and with greater evidence in the 1990s, wild-type yellow fever (WTYF) has re-emerged in both Africa and the Americas (Vasconcelos 2003a). In Brazil, the natural focus of WTYF is maintained within about 70% of the territory by a cycle that involves non-human primates and mosquitoes mainly of the genus Haemagogus (Vasconcelos et al. 1997a). Among the 28 known species of Haemagogus (Arnell 1973), three are considered as the main vectors in the natural cycle of WTYF. Haemagogus (Haemagogus) capricornii Lutz, 1904 is an efficient vector of WTYF virus (Waddell 1949). Because of similar behavior and morphology, it has often been confused with Haemagogus (Haemagogus) janthinomys Dyar, 1921. Since this latter species presents the greatest geographical distribution among the Brazilian species (Vasconcelos et al. 1997b), it is today considered to be the principal vector of WTYF virus. On the other hand, Hg. (Conopostegus) leucocelaenus (Dyar & Shannon, 1924) is the most common species of this genus in Brazil and has recently been found naturally infected with the WTYF virus in the State of Rio Grande do Sul (Vasconcelos 2003b). Knowledge of the feeding activity of culicids is of fundamental importance in assessing their participation in disease transmission (Guimarães and Victorio 1986). The present study was designed to observe the hematophagous behavior of populations of Hg. capricornii, Hg. janthinomys, and Hg. leucocelaenus in three different geographical regions of Brazil. The influences of temperature and relative humidity (RH) on the activity of these species at different times of the day and over the course of the seasons of the year were analyzed. Following the methodology of Guimarães et al. (1987), daytime and dusk captures were performed every two months and for five consecutive days at ground level during

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.

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.

Biology of Psorophora albigenu Under Laboratory Conditions

Abstract The present study investigates the effect of multiple immersions on Psorophora albigenu eggs and their development cycle under laboratory conditions. Engorged Ps. albigenu specimens were captured in January 2011 around the Transpantaneira Park Road, Mato Grosso, Brazil, using CO2-baited Centers for Disease Control and Prevention light traps. Psorophora albigenu eggs (n = 1274) were subjected to immersion, with a hatching rate between 49% and 73%. The Williams average showed a peak of 29% hatched eggs in the 3rd immersion; after 4–5 immersions, the effect of additional immersions was generally negligible. The average cycle for both males and females was 5.68 ± 1.00 days. This short development time from the egg stage to adult emergence followed the pattern seen in other species of the genus Psorophora.