Laboratory and field evaluation of the effects of the neonicotinoid imidacloprid on the oviposition response of Aedes (Stegomyia) aegypti Linnaeus (Diptera: Culicidae)

In this paper, we assessed the suitability of using the neonicotinoid imidacloprid with standard ovitraps by evaluating the ovicidal properties of imidacloprid and its influence on the oviposition response of gravid females of Aedes (Stegomyia) aegypti Linnaeus (Diptera: Culicidae). First, we calculated the imidacloprid lethal dose 99 (LD99) by exposing third instar larvae of the target species to different concentrations of the insecticide. Next, Ae. aegypti eggs were exposed to the imidacloprid LD99 for 24 h and hatching inhibition was recorded. Finally, we investigated any potential repellent effect of the imidacloprid solution on the oviposition response of gravid Aedes females in field and laboratory conditions. The LD99 obtained from larvae tests proved to be sufficient to keep any exposed eggs from hatching. No repellent effect was observed; females laid as many eggs in imidacloprid-treated ovitraps as in traps containing either clean water or temephos-treated water in both field and laboratory conditions. Our results indicate that imidacloprid is a suitable insecticide for treating ovitraps against Ae. aegypti.

Recent advances in the study of avian malaria: an overview with an emphasis on the distribution of Plasmodium spp in Brazil

Avian malaria parasites (Plasmodium) have a worldwide distribution except for Antarctica. They are transmitted exclusively by mosquito vectors (Diptera: Culicidae) and are of particular interest to health care research due to their phylogenetic relationship with human plasmodia and their ability to cause avian malaria, which is frequently lethal in non-adapted avian hosts. However, different features of avian Plasmodium spp, including their taxonomy and aspects of their life-history traits, need to be examined in more detail. Over the last 10 years, ecologists, evolutionary biologists and wildlife researchers have recognized the importance of studying avian malaria parasites and other related haemosporidians, which are the largest group of the order Haemosporida by number of species. These studies have included understanding the ecological, behavioral and evolutionary aspects that arise in this wildlife host-parasite system. Molecular tools have provided new and exiting opportunities for such research. This review discusses several emerging topics related to the current research of avian Plasmodium spp and some related avian haemosporidians. We also summarize some important discoveries in this field and emphasize the value of using both polymerase chain reaction-based and microscopy-based methods in parallel for wildlife studies. We will focus on the genus Plasmodium, with an emphasis on the distribution and pathogenicity of these parasites in wild birds in Brazil.

Can Mosquito Magnet® substitute for human-landing catches to sample anopheline populations?

The efficiency of the Mosquito Magnet Liberty PlusTM (MMLP) trap was evaluated in comparison to human-landing catches (HLCs) to sample anopheline populations in Jabillal, state of Bolivar, southern Venezuela. The village comprised 37 houses and a population of 101; malaria in this village is primarily due to Plasmodium vivax and the Annual Parasite Index is 316.8 per 1,000 population. A longitudinal study was conducted between June 2008-January 2009 for three nights per month every two months between 17:30 pm-21:30 pm, a time when biting mosquitoes are most active. Anopheles darlingi and Anopheles nuneztovari were the most common species collected by both methods, whereas Anopheles marajoara was more abundant according to the HLC method. The MMLP trap was more efficient for collecting An. nuneztovari [63%, confidence interval (CI): 2.53] than for collecting An. darlingi (31%, CI: 1.57). There were significant correlations (p < 0.01) between the two methods for An. darlingi [Pearson correlation (R²) = 0.65] and An. nuneztovari (R² = 0.48). These preliminary results are encouraging for further investigations of the use of the MMLP trap for monitoring anopheline populations in remote malaria-endemic areas in the Amazon Basin.

Why do we need alternative tools to control mosquito-borne diseases in Latin America?

In this opinion paper, we discuss the potential and challenges of using the symbiont Wolbachia to block mosquito transmitted diseases such as dengue, malaria and chikungunya in Latin America.

Culicidae (Diptera) selection of humans, chickens and rabbits in three different environments in the province of Chaco, Argentina

Studies were conducted to determine the selection of humans, chickens and rabbits by Culicidae in three different environments in the province of Chaco, Argentina. Mosquitoes were collected fortnightly using cylindrical metal traps containing animal bait (chickens and rabbits). The mosquitoes were collected between June 2001-May 2002. During the same period and with the same frequency, mosquitoes biting the human operators of the traps were collected during the first 15 min of exposure within different time intervals: from 09:00 am-11:00 am, 01:00 pm-03:00 pm, 05:00 pm-07:00 pm and 09:00 pm-10:00 pm. A total of 19,430 mosquitoes of 49 species belonging to 10 genera were collected. Culex species mainly selected chicken bait and Wyeomyia species selected rabbit bait. Ochlerotatus and Psorophora species were more abundant in rabbit-baited traps. Anopheles triannulatus, Coquillettidia nigricans, Ochlerotatus scapularis, Mansonia titillans and Psorophora albigenu showed a strong attraction for human bait. The Anopheles, Coquillettidia, Culex and Mansonia species were more active between 05:00 pm-09:00 pm, while Ochlerotatus, Psorophora, Haemagogus and Wyeomyia were most active from 09:00 am-07:00 pm. This study provides additional information about the biology and ecology of arbovirus vectors in Chaco.

Mosquitoes of eastern Amazonian Ecuador: biodiversity, bionomics and barcodes

Two snapshot surveys to establish the diversity and ecological preferences of mosquitoes (Diptera: Culicidae) in the terra firme primary rain forest surrounding the Tiputini Biodiversity Station in the UNESCO Yasuní Biosphere Reserve of eastern Amazonian Ecuador were carried out in November 1998 and May 1999. The mosquito fauna of this region is poorly known; the focus of this study was to obtain high quality link-reared specimens that could be used to unequivocally confirm species level diversity through integrated systematic study of all life stages and DNA sequences. A total of 2,284 specimens were preserved; 1,671 specimens were link-reared with associated immature exuviae, all but 108 of which are slide mounted. This study identified 68 unique taxa belonging to 17 genera and 27 subgenera. Of these, 12 are new to science and 37 comprise new country records. DNA barcodes [658-bp of the mtDNA cytochrome c oxidase ( COI ) I gene] are presented for 58 individuals representing 20 species and nine genera. DNA barcoding proved useful in uncovering and confirming new species and we advocate an integrated systematics approach to biodiversity studies in future. Associated bionomics of all species collected are discussed. An updated systematic checklist of the mosquitoes of Ecuador (n = 179) is presented for the first time in 60 years.

COI barcode versus morphological identification of Culex ( Culex ) (Diptera: Culicidae) species: a case study using samples from Argentina and Brazil

Sequences of the cytochrome c oxidase subunit I (COI) mitochondrial gene from adults of 22 Culex ( Culex ) species from Argentina and Brazil were employed to assess species identification and to test the usefulness of COI for barcoding using the best close match (BCM) algorithm. A pairwise Kimura two-parameter distance matrix including the mean intra and interspecific distances for 71 COI barcode sequences was constructed. Of the 12 COI lineages recovered in the Neighbour-joining topology, five confirmed recognised morphological species ( Cx. acharistus , Cx. chidesteri , Cx. dolosus , Cx. lygrus and Cx. saltanensis ) with intraspecific divergences lower than 1.75%. Cx. bilineatus is formally resurrected from the synonymy of Cx. dolosus . Cx. maxi , Cx. surinamensis and the Coronator group species included were clustered into an unresolved lineage. The intraspecific distance of Cx. pipiens (3%) was almost twice the interspecific between it and Cx. quinquefasciatus (1.6%). Regarding the BCM criteria, the COI barcode successfully identified 69% of all species. The rest of the sequences, approximately 10%, 18% and 3%, remained as ambiguously, mis and unidentified, respectively. The COI barcode does not contain enough information to distinguish Culex ( Cux. ) species.

The Plasmodium bottleneck: malaria parasite losses in the mosquito vector

Nearly one million people are killed every year by the malaria parasite Plasmodium. Although the disease-causing forms of the parasite exist only in the human blood, mosquitoes of the genus Anopheles are the obligate vector for transmission. Here, we review the parasite life cycle in the vector and highlight the human and mosquito contributions that limit malaria parasite development in the mosquito host. We address parasite killing in its mosquito host and bottlenecks in parasite numbers that might guide intervention strategies to prevent transmission.

Effectiveness of Mosquito Magnet&#174; trap in rural areas in the southeastern tropical Atlantic Forest

Traps are widely employed for sampling and monitoring mosquito populations for surveillance, ecological and fauna studies. Considering the importance of assessing other technologies for sampling mosquitoes, we addressed the effectiveness of Mosquito Magnet® Independence (MMI) in comparison with those of the CDC trap with CO2 and Lurex3® (CDC-A) and the CDC light trap (CDC-LT). Field collections were performed in a rural area within the Atlantic Forest biome, southeastern state of São Paulo, Brazil. The MMI sampled 53.84% of the total number of mosquitoes, the CDC-A (26.43%) and CDC-LT (19.73%). Results of the Pearson chi-squared test (χ2) showed a positive association between CDC-LT and species of Culicini and Uranotaeniini tribes. Additionally, our results suggested a positive association between CDC-A and representatives of the Culicini and Aedini tribes, whereas the MMI was positively associated with the Mansoniini and Sabethini as well as with Anophelinae species. The MMI sampled a greater proportion (78.27%) of individuals of Anopheles than either the CDC-LT (0.82%) or the CDC-A traps (20.91%). Results of the present study showed that MMI performed better than CDC-LT or CDC-A in sampling mosquitoes in large numbers, medically important species and assessing diversity parameters in rural southeastern Atlantic Forest.

Influência da temperatura sobre a longevidade, fecundidade e atividade hematofágica de Aedes (Stegomyia) albopictus Skuse, 1894 (Diptera, Culicidae) sob condições de laboratório

Influence of temperature on longevity, fecundity, and haematophagic activity of Aedes (Stegomyia) albopictus Skuse, 1894 (Diptera, Culicidae) under laboratory condition. Based on adults of Aedes albopictus maintained under four constant temperatures, 15ºC, 20ºC, 25ºC and 30ºC, longevity of males and females, fecundity, eggs viability, number of days from emergence to the first bloodsucking, and duration of the preoviposition period were observed. The average of the longevity for female was 19.45, 59.35, 61.55 and 42.72 days, under 15ºC, 20ºC, 25ºC and 30ºC, respectively. The greatest average number of bloodsucking per female was 8.32, under 25ºC. The average number of eggs per female was 1.00, 73.91, 269.87 and 183.69, and the greatest rates of viable eggs per female was 25ºC and 30ºC. The haematophagic activities and the oviposition were significantly influenced by temperature.

Exigências térmicas de Aedes (Stegomyia) albopictus Skuse, 1894 (Diptera, Culicidae) em condições de laboratório

Thermal requirements of Aedes (Stegomyia) albopictus Skuse, 1894 (Diptera, Culicidae) under laboratory conditions. Allochtonous species of Ae. albopictus in the American continent can be found in fourteen Brazilian states - about fifteen years had been elapsed since the first report of the presence of this species in Brazilian territory. Considering its potential epidemiological importance and its adaptation to several habitats, it was determined, for this species, the threshold temperature and the thermal constant for egg, larval and pupal stages under laboratory conditions under four constant temperatures and 12:12 hours light-dark photoperiod. The threshold temperature for the egg phase and for the first instar were quite similar: 9.07 ºC (K=214.46 degree days) and 9.23 ºC (K= 36.64 degree days), respectively. For 2nd, 3rd and 4th instar, the basal-temperature was higher, oscilating between 12.26 ºC and 13.95 ºC. The threshold temperature for the complete larval stage and for the pupal stage were 12.03 ºC (K= 99.48 degree days) and 11.87 ºC (K=32.40 degree days) for males and 11.95 ºC (K=110.11 degree days) and 11.60 ºC (K=35.30 degree days) for females, respectively.

Ultrastructure of the eggs of two species of Anopheles (Anopheles) Meigen (Diptera, Culicidae)

Egg ultrastructure of two morphologicaly similar species of the Arribalzagia Series, Anopheles (A.) costai Fonseca & Ramos, 1939 and A. (A.) mediopunctatus (Lutz, 1903) are described and illustrated using scanning electron micrographs. Although similar in the adult stage, male genitalia structures and larval and pupal stages, the eggs of these species are distinct. The eggs of A. costai and A. mediopunctatus are compared with that of A. forattinii Wilkerson & Sallum, 1999. Incomplete illustration of egg of A. forattinii is provided for comparison.

O acervo de mosquitos (Diptera, Culicidae) de Nelson L. Cerqueira na Coleção de Invertebrados do Instituto Nacional de Pesquisas da Amazônia, Manaus, Brasil

Registra-se a descoberta de espécimes de mosquitos que pertenciam a Nelson L. Cerqueira, e estão sendo depositados na coleção de Invertebrados do Instituto Nacional de Pesquisas da Amazônia. A coleção contém 2.046 espécimes adultos e 387 lâminas representando 261 espécies, 22 gêneros, incluindo 51 parátipos de 34 espécies. Mais de 90% dos espécimes foram coletados no Brasil dos quais metade são do Estado do Amazonas. As espécies representadas neste acervo são listadas indicando o número de espécimes para cada tipo de preparação e as localidades de coleta. O material tipo também é listado, incluindo os dados dos rótulos de identificação e de procedência, bem como outras informações pertinentes.

Culicinae (Diptera, Culicidae) ocorrentes no Estado do Rio Grande do Sul, Brasil

Este trabalho lista as espécies e aponta a ocorrência de Culicinae, com base em coletas de adultos realizadas no período de setembro de 2001 a agosto de 2002, em 11 zonas fisiográficas do Estado, busca de informações bibliográficas e verificação de exemplares em coleções. São relacionadas 57 espécies, sendo que 22 constituem novas ocorrências para o Rio Grande do Sul. São ampliados os locais de ocorrência de Aedeomyia squamipennis, Culex chidesteri, Culex quinquefasciatus, Haemagogus leucocelaenus, Mansonia titillans, Ochlerotatus albifasciatus, Ochlerotatus crinifer, Ochlerotatus fluviatilis, Ochlerotatus scapularis, Ochlerotatus serratus, Psorophora confinnis, Psorophora ferox, Sabethes aurescens, Trichoprosopon pallidiventer e Uranotaenia lowii.

Revision of the Leucosphyrus group of Anopheles (Cellia) (Diptera, Culicidae)

Revision of the Leucosphyrus Group of Anopheles (Cellia) (Diptera, Culicidae). This is a comprehensive revision of 20 species of the Leucosphyrus Group of the Neomyzomyia Series of Anopheles (Cellia). Morphological description of the adults, male and female, male genitalia, pupa and fourth-instar larva are provided for each taxon in addition to bionomics, distribution data and systematic discussion for each species, including diagnostic characters. Identification keys for females and fourth-instar larvae are provided. When possible medical importance of each species is included. Illustrations of of the adults, fourth-instar larvae and pupae are provided. Distribution maps for each species are mainly based on the material examined; however, when possible published data were also used. Tables on adult character variations, fourth-instar larval and pupal setal branching are included as appendices. A neotype for An. takasagoensis Morishita and An. sulawesi Koesoemawinangoen, and a lectotype for An. balabacensis Baisas, are designated. The authorship of An. sulawesi previously cited as Waktoedi is corrected to Koesoemawinangoen.