Breeding habitats and seasonal prevalences of the dengue vector mosquitoes, Aedes (Stegomyia) species in and around human houses were suveyed from 1994 to 1996 in South Sulawesi, Indonesia. The latter study was also carried out in Okonawa, Japan for comparative study.
Malaria transmission is dependent upon many hydrology-driven ecological factors that directly affect the vectorial competence, including the presence of suitable habitats for the development of anopheline larvae. Larval habitats were identified and characterized at three malaria endemic villages (Ban Khun Huay, Ban Pa Dae, and Ban Tham Seau) in Mae Sot district, Tak Province, in northwestern Thailand between July 2002 and June 2003. The Global Positioning System (GPS) was used to provide precise locational data for the spatial distribution of anopheline mosquito larvae and their habitats. Ten habitat categories were identified. Eighteen adult Anopheles species were identified from larvae in all the surveyed habitats. An. minimus was the most common species throughout the year. The relationship between eight abiotic variables (temperature, hardness, carbon dioxide, dissolved oxygen, nitrate, phosphate, silica and pH) and the abundance of four major species of malaria vectors (An. (Cel.) dirus, An. (Cel.) minimus, An. (Cel.) maculatus, and An. (Cel.) sawadwongporni), and six species of non-vectors (An. (Cel.) kochi, An. (Cel.) jamesii, An. (Ano.) peditaeniatus, An. (Ano.) barbirostris, An. (Ano.) campestris, and An (Cel.) vagus) larvae was investigated. The results from the multiple regression models suggest that hardness, water temperature and carbon dioxide are the best predictor variables associated with the abundance of An. minimus larvae (p < 0.001); water pH for An. dirus larvae (p < 0.001); temperature and pH for An. kochi larvae (p < 0.01); temperature and silica concentration for An. jamesii larvae (p < 0.001); dissolved oxygen and silica concentration for An. campestris larvae (p < 0.001); and pH and silica concentration for An. vagus larvae (p < 0.001). We could not identify key environmental variables for An. maculatus, An. sawadwongporni, An. peditaeniatus, and An. barbirostris. PMID:15906641
Kengluecha, Ampornpan; Singhasivanon, Pratap; Tiensuwan, Montip; Jones, James W; Sithiprasasna, Ratana
We sampled 291 bodies of water for Anopheles larvae around three malaria-endemic villages of Ban Khun Huay, Ban Pa Dae, and Ban Tham Seau, Mae Sot district, Tak Province, Thailand during August 2001-December 2002 and collected 4,387 larvae from 12 categories of breeding habitat types. We modeled surface slope and wetness indices to identify the extent and spatial pattern of potential mosquito breeding habitats by digitizing base topographical maps of the study site and overlaying them with coordinates for each larval habitat. Topographical contours and streamlines were incorporated into the Geographical Information System (GIS). We used Global Positioning System (GPS) instruments to locate accurately each field observed breeding habitat, and produced a 30-m spatial resolution Digital Elevation Model (DEM). The slope (of less than 12 degrees) and wetness (more than 8 units) derived from spatial modeling were positively associated with the abundance of major malaria vectors An. dirus, An. maculatus, An. minimus, and An. sawadwongporni. These associations permit real-time monitoring and possibly forecasting of the distributions of these four species, enabling public health agencies to institute control measures before the mosquitos emerge as adults and transmit disease. PMID:15115121
Sithiprasasna, Ratana; Linthicum, Kenneth J; Liu, Gang-Jun; Jones, James W; Singhasivanon, Pratap
Septic tank mosquitoes in Abia State University Okigwe, south-eastern Nigeria were studied using exit traps between November 1988 and April 1989. The results were revealing and striking. Apart from the common septic tank mosquitoes, Culex p. quinquefasciatus, Cu. cinereus and Aedes aegypti, which have been previously commonly found breeding in ammonia and nitrate-rich waters of latrines and septic tanks, the other species, Cu. horridus, Cu. tigripes and Aedes vittatus, have not been commonly reported as colonizing septic tanks in Nigeria. Three out of these six mosquito species observed are vectors of human diseases: Aedes aegypti and Aedes vittatus are vectors of Yellow fever and Cu. p. quinquefasciatus is a potential vector of Bancroftian filariasis and a world-wide vector of various arboviruses. The fact that these mosquito vectors are able to breed in highly polluted waters of septic tanks during the harsh dry months when most surface water bodies are dry is epidemiologically important. The breeding of these mosquito vectors of human diseases around human dwellings indicates an intense man-vector contact creating a high level risk to the crowded urban population. The public health implications of this urbanization/modernization problem and solutions are discussed. PMID:8508215
Nwoke, B E; Nduka, F O; Okereke, O M; Ehighibe, O C
This study was carried out in Minna, Nigeria, to elucidate the dry season breeding ecology of mosquitoes in the area thus, providing a basis for all-year-round effective implementation of informed larviciding interventions. Mosquito larvae were sampled bi-weekly between the hours of 0800 and 1100 from randomly selected larval breeding habitats in the city, using a 350 mL capacity Dipper. The physical characteristics of the selected habitats were evaluated and related to larval productivity. T...
Olayemi, I. K.; Idris, B.; Omalu, I. C. J.; Odeyemi, O. M.
Objective To determine the larval habitats of mosquito fauna and possible impact of land use/ land cover changes on the epidemiology of mosquito-borne diseases in Osogbo metropolis, Southwestern, Nigeria. Methods All accessible larval habitats were surveyed between May and September, 2011 in Osogbo metropolis while Land Use/ Land cover of the city was analyzed using 2 Lansat Multispectral Scanner satellite imagery of SPOT 1986 and LANDSAT TM 2009. Results A total of six species namely, Aedes aegypti, Aedes albopictus, Aedes vittatus, Anopheles gambiae complex, Culex quinquefasciatus and Eretmapodite chrysogaster were encountered during the study. The occurrence and contribution of disused tyres was significantly higher (Pseptic tanks/ drums, ground pools/open drains and discarded containers to the breeding of mosquitoes (P>0.05). The accessible land use/ land covered of the study area between 1986 and 2009 showed that the wet land coverage and settlement area increased from 0.19 to 9.09 hectare and 1.00 to 2.01 hectare respectively while the forest area decreased from 60.18 to 50.14 hectare. Conclusion The contribution of the habitats coupled with the increasing rate of flooded environment which could provide ample breeding sites for mosquitoes call for sustained environmental sanitation and management in Osogbo metropolis.
Adeleke, Monsuru Adebayo; Adebimpe, Wasiu Olalekan; Hassan, AbdulWasiu Oladele; Oladejo, Sunday Olukayode; Olaoye, Ismail; Olatunde, Ganiyu Olatunji; Adewole, Taiwo
A survey was conducted to evaluate the number of tree-hole breeding mosquito species and their distribution in the six principal woodland types in Israel. Out of approximately 3,000 mature trees examined, only 38 contained holes that retained water for extended periods of time, and breeding mosquitoes were observed in 27 of them. Two specialized tree-hole breeders, Aedes pulchritarsis Rondani and Aedes geniculatus Oliver, were found breeding at several sites in northern Israel, always at locations 500 m above sea level (a.s.l) and with high annual precipitation. Aedes albopictus Skuse which, in Israel, is known as an opportunistic container breeder, was found in this study to have adapted remarkably well to breeding in tree holes and was found in most forest types investigated and in most tree species which had adequate tree holes. Two other species, Culiseta annulata Schrank and Culex pipiens Linnaeus instars, were found in one of the tree holes, but did not survive to reach maturity. PMID:22548543
Müller, Günter C; Kravchenko, Vasiliy D; Junnila, Amy; Schlein, Yosef
Artificial container-breeding mosquitoes, such as Aedes aegypti, Ae. albopictus, and Culex pipiens, are well-recognized vectors of diseases throughout the world. Cemeteries are considered major sources of mosquitoes and the results of more than 30 studies concerning mosquitoes in cemeteries have been published over the last decade. The characteristics of these environments in regard to the availability of resources for mosquito development were discussed. Also, studies about early detection of Aedes vectors, ecological issues, and mosquito control performed in cemeteries were reviewed. Among 31 mosquito species found breeding in cemeteries from 16 countries, the invasive Ae. aegypti and Ae. albopictus were the most frequent ones. Species of the genus Ochlerotatus, Culex, Toxorhynchites, Culiseta, Armigeres, Lutzia, Uranotaenia, and Tripteroides were also reported. Overall, cemeteries are highly suitable habitats for artificial container-breeding mosquitoes due to the great availability of the different resources that they need (i.e. sugar substances, blood, shelter and water-filled containers). In addition, these places are mostly ideal settings to perform studies in urbanized areas because of high mosquito abundance, heterogeneity of macro- and microhabitats, and an easier access in comparison with private premises. However, the feasibility of a cemetery as a study area must be evaluated in each case considering the objectives of the study and cemetery characteristics. PMID:17300639
Full Text Available This study was carried out in Minna, Nigeria, to elucidate the dry season breeding ecology of mosquitoes in the area thus, providing a basis for all-year-round effective implementation of informed larviciding interventions. Mosquito larvae were sampled bi-weekly between the hours of 0800 and 1100 from randomly selected larval breeding habitats in the city, using a 350 mL capacity Dipper. The physical characteristics of the selected habitats were evaluated and related to larval productivity. The results indicated that Anopheles mosquitoes constituted 55.00% of all larvae collected, followed by Culex (36.29% and Aedes (17.49%. The patterns of mean monthly density distribution of the three mosquito Genera were similar, i.e., decreasing significantly (pAnopheles and Aedes preferring the Drains (24.40±5.13 and 14.20±5.12 larvae/sampling day, respectively and Culex mosquitoes encountered more frequently in the Swamps (16.80±6.22 larvae/sampling day. The Drains were the most productive habitats, accounting for over 50% larval production during the period, distantly followed by the Swamp (31.60±16.38 larvae/sampling day while, the densities of larvae in the Wells and Rivers were significantly low (7.40±7.79 and 3.40±5.24 larvae/sampling day, respectively. Again, in terms of physical attributes, the Drains were the most ideal habitat for larval development, been relatively small (diameter = 2.30±0.00 m; most shallow (depth = 0.14±0.01 m; warmest (27.52±0.48°C and nearest to human habitations (2.80±0.00 m. The epidemiological implications of these results were discussed and concluded that targeting dry season larviciding interventions at the productive larval breeding habitats will go a long way in reducing the menace of mosquito-borne diseases in Minna.
The proliferation of artificial container habitats in urban areas has benefitted urban adaptable mosquito species globally. In areas where mosquitoes transmit viruses and parasites, it can promote vector population productivity and fuel mosquito-borne disease outbreaks. In Britain, storage of water in garden water butts is increasing, potentially expanding mosquito larval habitats and influencing population dynamics and mosquito-human contact. Here we show that the community composition, abundance and phenology of mosquitoes breeding in experimental water butt containers were influenced by urbanisation. Mosquitoes in urban containers were less species-rich but present in significantly higher densities (100.4±21.3) per container than those in rural containers (77.7±15.1). Urban containers were dominated by Culex pipiens (a potential vector of West Nile Virus [WNV]) and appear to be increasingly exploited by Anopheles plumbeus (a human-biting potential WNV and malaria vector). Culex phenology was influenced by urban land use type, with peaks in larval abundances occurring earlier in urban than rural containers. Among other factors, this was associated with an urban heat island effect which raised urban air and water temperatures by 0.9°C and 1.2°C respectively. Further increases in domestic water storage, particularly in urban areas, in combination with climate changes will likely alter mosquito population dynamics in the UK.
Townroe, Susannah; Callaghan, Amanda
A review and synthesis of existing information was used to develop a model for evaluating the potential suitability of habitat along the coast of Maine for breeding American eider (Somateria mollissima dresseri). The model is scaled to produce an index from 0 (unsuitable habitat) to 1.0 (optimal habitat). Habitat suitability index models are designed for use with the Habitat Evaluation Procedures previously developed by the US Fish and Wildlife Service. Guidelines for model application are provided. 51 refs., 3 figs., 5 tabs.
Blumton, A.K.; Owen, R.B. Jr.; Krohn, W.B.
Studies on mosquito breeding and its control through Gambusia affinis in nursery and paddy fields after transplantation of seedlings were carried out during June to October 1991 in about 10 ha rice field area. Six anopheline species, viz. An. culicifacies, An. annularis, An. subpictus, An. nigerrimus, An. barbirostris and An. aconitus, and four culicine species, viz. Cx. tritaeniorhynchus, Cx. bitaeniorhynchus, Cx. quinquefasciatus, and Aedes sp. could be identified. These were found breeding in rice fields with fluctuations in their percentage composition, exhibiting species succession in different months. G. affinis survived well in submerged rice fields and provided 87.8% mosquito larval control. In rice fields which exhibited intermittent drying up leading to formation of pools, puddles etc., moderate larval control was achieved. However, in nursery rice fields, this method was not applicable. Mosquito larval control through larvivorous fish in rice fields can be achieved but the method has limitations. PMID:8405595
Prasad, H; Prasad, R N; Haq, S
A large number of source materials were collected for isolating entomopathogenic bacteria from larval mosquito habitats in Kirinyaga District, Kenya. Mosquito-toxic bacteria were included among the numerous types of microorganisms isolated from the habitats. The pathogenic isolates shared common structural characteristics; they were gram-positive, spore-forming bacilli that produced parasporal inclusions conferring broad-spectrum larvicidal activity against Anopheles, Culex and Aedes mosquitoes. Based on structural and growth characteristics, coupled with larvicidal activity, the pathogenic isolates were tentatively identified as variants of Bacillus thuringiensis. Although the collection consisted of a variety of items including soil, silt and mud, the most productive materials were larval bodies. Using healthy mosquito larvae held in a fully permeable plastic bottle, a baiting technique was developed as a means of recovering bacteria from the environment. PMID:1583497
Asimeng, E J; Mutinga, M J
Malaria is a major health problem in Ethiopia. Anopheles arabiensis, which inhabits and breeds in a variety of aquatic habitats, is the major mosquito vector for malaria transmission in the region. In the Amhara region of Ethiopia, mosquito breeding sites are heterogeneously distributed. Therefore, accurate characterization of aquatic habitats and potential breeding sites can be used as a proxy to measure the spatial distribution of malaria risk. Satellite remote sensing provides the ability to map the spatial distribution and monitor the temporal dynamics of surface water. The objective of this study is to map the probability of surface water accumulation to identify potential vector breeding sites for Anopheles arabiensis using remote sensing data from sensors at multiple spatial and temporal resolutions. The normalized difference water index (NDWI), which is based on reflectance in the green and the near infrared (NIR) bands were used to estimate fractional cover of surface water. Temporal changes in surface water were mapped using NDWI indices derived from MODIS surface reflectance product (MOD09A1) for the period 2001-2012. Landsat TM and ETM+ imagery were used to train and calibrate model results from MODIS. Results highlighted interannual variation and seasonal changes in surface water that were observed from the MODIS time series. Static topographic indices that estimate the potential for water accumulation were generated from 30 meter Shuttle Radar Topography Mission (SRTM) elevation data. Integrated fractional surface water cover was developed by combining the static topographic indices and dynamic NDWI indices using Geographic Information System (GIS) overlay methods. Accuracy of the results was evaluated based on ground truth data that was collected on presence and absence of surface water immediately after the rainy season. The study provided a multi-sensor approach for mapping areas with a high potential for surface water accumulation that are potential breeding habitats for anopheline mosquitoes. The resulting products are useful for public health decision making towards effective prevention and control of the malaria burden in the Amhara region of Ethiopia.
Midekisa, A.; Wimberly, M. C.; Senay, G. B.
Culicinomyces clavosporus was isolated from diseased larvae of Culex pipiens collected from brackish water habitat. Pure cultures of the fungus were grown on nutrient agar media. In the laboratory, the Egyptian isolate of the fungus was bioassayed against first instar larvae of Aedes caspius, Cx. antennatus and Cx. pipiens. The estimated LC50's for Ae. caspius, Cx. antennatus and Cx. pipiens were 4.4 x 10(2), 7.6 x 10(2) and 11.8 x 10(2) conidia/ml, respectively. Field studies were undertaken in a variety of habitats supporting populations of mosquitoes in Mahalet Marhoom, El-Gharbia Governorate, in the summer of 1999. Evaluations included artificial pool studies and field trials. The fungus was applied once to 3 different natural breeding habitats of mosquitoes at a dose rate of 10(10) conidia/m2. Cx. clavosporus introduction into unpolluted rice field that had high densities of Cx. antennatus and low densities of Anopheles tenebrosus Doenitz and Cx. perexiguus resulted in 100% control of the larvae 5 days post treatment. Introduction of the fungus into brackish water habitat supporting large brood of Ae. caspius, and few numbers of Culiseta longiareolata (Macquart), Cx. Pusillus, Cx. perexiguus and Cx. pipiens was equally effective. Dissection and examinations of larvae from both sites confirmed infection by the fungus. However, introduction of the fungus into a drain supporting high population density of Cx. pipiens was not effective. Microscopic examination of larvae removed from this site revealed that the conidia failed to germinate and penetrate the host cuticle. The presence of organic pollution in the breeding site drastically reduced the infectivity of the fungus. Thus, the fungus appears promising as a possible limiting factor for mosquito populations, and eventually its use in control of mosquitoes merits further investigations. PMID:12739818
Seif, Amal I; Shaarawi, Fatma A
In Mali, anopheline mosquito populations increase sharply during the rainy season, but are barely detectable in the dry season. This study attempted to identify the dry season mosquito breeding population in and near the village of Bancoumana, Mali, and in a fishing hamlet 5 km from this village and adjacent to the Niger River. In Bancoumana, most larval habitats were human made, and dried out in January-February. In contrast, in the fishing hamlet, productive larval habitats were numerous and found mainly during the dry season (January-May) as the natural result of drying riverbeds. Adult mosquitoes were abundant during the dry season in the fishermen hamlet and rare in Bancoumana. To the extent that the fishermen hamlet mosquito population seeds Bancoumana with the advent of the rainy season, vector control in this small hamlet may be a cost-effective way to ameliorate malaria transmission in the 40-times larger village. PMID:17620634
Sogoba, Nafomon; Doumbia, Seydou; Vounatsou, Penelope; Baber, Ibrahima; Keita, Moussa; Maiga, Mamoudou; Traoré, Sékou F; Touré, Abdoulaye; Dolo, Guimogo; Smith, Thomas; Ribeiro, José M C
Full Text Available Abstract Introduction By 2030, more than 50% of the African population will live in urban areas. Controlling malaria reduces the disease burden and further improves economic development. As a complement to treated nets and prompt access to treatment, measures targeted against the larval stage of Anopheles sp. mosquitoes are a promising strategy for urban areas. However, a precise knowledge of the geographic location and potentially of ecological characteristics of breeding sites is of major importance for such interventions. Methods In total 151 km2 of central Dar es Salaam, the biggest city of Tanzania, were systematically searched for open mosquito breeding sites. Ecologic parameters, mosquito larvae density and geographic location were recorded for each site. Logistic regression analysis was used to determine the key ecological factors explaining the different densities of mosquito larvae. Results A total of 405 potential open breeding sites were examined. Large drains, swamps and puddles were associated with no or low Anopheles sp. larvae density. The probability of Anopheles sp. larvae to be present was reduced when water was identified as "turbid". Small breeding sites were more commonly colonized by Anopheles sp. larvae. Further, Anopheles gambiae s.l. larvae were found in highly organically polluted habitats. Conclusions Clear ecological characteristics of the breeding requirements of Anopheles sp. larvae could not be identified in this setting. Hence, every stagnant open water body, including very polluted ones, have to be considered as potential malaria vector breeding sites.
The used tire trade has facilitated the introduction, spread, and establishment of the Asian tiger mosquito, Aedes albopictus, and other mosquito species in several countries of America, Africa, Oceania, and Europe. A strategy for detecting these imported mosquito vectors was developed in Spain during 2003-2004 by EVITAR (multidisciplinary network for the study of viruses transmitted by arthropods and rodents). A survey in 45 locations found no invasive species. Eight autochthonous species of mosquitoes were detected in used tires, including Culex pipiens, Cx. hortensis, Cx. modestus, Anopheles atroparvus, An. claviger, Culiseta longiareolata, Cs. annulata, and Aedes caspius. Dominant species were Cx. pipiens and Cs. longiareolata. Aedes caspius was found in only once, near its natural breeding habitat. Considering the recent discovery of an established population of Ae. albopictus in Catalonia, the increasing commerce of used tires in Spain for recycling, storage, and recapping might greatly contribute to the rapid spread of this species across the Iberian Peninsula. PMID:17633420
Roiz, D; Eritja, R; Escosa, R; Lucientes, J; Marquès, E; Melero-Alcíbar, R; Ruiz, S; Molina, R
Studies on entomological monitoring: mosquito species frequency in riverine habitats of the Igarapava Dam, Southern Region, Brazil Estudos em monitoramento entomológico: mudanças na freqüência de mosquitos em habitats ripários da usina hidroelétrica de Igarapava, Sudeste do Brasil
Full Text Available Diversity of mosquito species was evaluated in different habitats before and after the Igarapava reservoir flooding in the Grande River, Southern Cerrado of Brazil. We aimed at verifying changes in these mosquito populations in consequence of the lake formation. Four habitats were selected as sampling stations: peridomiciliary habitat, pasture, "veredas" and gallery forest patch. Bimonthly collections were made with the Shannon trap and human bait, including diurnal, crepuscular and nocturnal period of mosquito activity. The Shannon Index results from the potential vectors were compared using Student t-test. Aedes scapularis, Anopheles darlingi and An. albitarsis senso latu seasonal abundance were described with moving average and compared using chi2 test. There were changes in the mosquito frequency in the habitats, except for the "veredas" that was 13 km away from the catchment area. The altering in mosquito species seasonal abundance suggests breeding places expansion. Diversity indexes can be used to monitor changes in mosquito vector population in environments where abrupt disturbance can alter disease transmission cycles.Avaliou-se a diversidade de mosquitos em diferentes habitats antes e depois da formação do reservatório de Igarapava no Rio Grande, Cerrado do Sudeste do Brasil, com objetivo de verificar alteração nessas populações de mosquitos. Quatro habitats foram selecionados como sítios de coleta: a peridomicílio rural, b pastagem, c veredas e d mata ciliar. Realizaram-se coletas bimestrais com isca humana e armadilha de Shannon, incluindo períodos de atividade culicídea diurna, crepuscular vespertina e noturna. Os resultados do Índice de Shannon para os potenciais vetores nos diferentes habitats foram comparados pelo teste t de Student. As abundâncias sazonais de Aedes scapularis, Anopheles darlingi e Anopheles albitarsis s.l., foram descritas com a média móvel e comparadas com o teste chi2. Houve alteração nas freqüências dos mosquitos nos habitats, com exceção das veredas, que estavam afastadas 13 km da área de influência do reservatório. A modificação nas abundâncias sazonais dos potenciais vetores sugere o incremento de criadouros após a formação do reservatório. Índices de diversidade são ferramentas úteis para monitorar populações de mosquitos vetores em ambientes cujas mudanças drásticas podem alterar ciclos de transmissão de doenças transmitidas por vetores.
Rosa Maria Tubaki
A 2-yr (1988-1989) survey of mosquitoes breeding in surface water was done in an area of the Mahaweli Project of Sri Lanka that underwent irrigation development and human settlement during the preceding 3 yr. In total, 78,649 immatures of 42 species were collected during the survey. Species of medical importance in the area were Anopheles annularis van der Wulp, An. culicifacies Giles, An. jamesii Theobald, An. nigerrimus Giles, An. subpictus Grassi, An. vagus Doenitz, An. varuna Iyengar, Mansonia annulifera (Theobald), Ma. uniformis (Theobald), Culex fuscocephala Theobald, Cx. gelidus Theobald, Cx. pseudovishnui Colless, Cx. tritaeniorhynchus Giles, and Cx. vishnui Theobald. These and other species used breeding habitats associated with irrigation development (i.e., canals, reservoirs, seepage pools, and rice fields) as well as natural habitats (i.e., rainwater pools, riverbed pools, streams, and marshes). Trends in the use of breeding habitats that were observed with the onset of irrigated rice cultivation in 1987, continued during the period under stable irrigation in 1988 and 1989. Mosquito species richness declined, but species equitability (as indexed by Shannon-Weaver diversity values) did not change. The overall study showed that ecosystem changes concomitant with irrigation development in the Mahaweli Project resulted in long-term changes in the composition of the mosquito fauna, which was characterized by the increasing dominance of species with the potential to transmit human pathogens. PMID:7932596
Amerasinghe, F P; Indrajith, N G
We investigated the bacterial diversity of microbial communities in water-filled, human-made and natural container habitats of the mosquitoes Aedes aegypti and Aedes albopictus in suburban landscapes of New Orleans, Louisiana in 2003. We collected water samples from three classes of containers, including tires (n=12), cemetery urns (n=23), and miscellaneous containers that included two tree holes (n=19). Total genomic DNA was extracted from water samples, and 16S ribosomal DNA fragments (oper...
The study of tree-hole breeding mosquitoes was carried out in the tropical rainforest of Imo State Nigeria (two rural areas and two forest reserves in some parts of Orlu Senatorial Zone) between May-October 2002. Using standard entomological procedures, two macrohabitats (natural tree-holes and bamboo traps) and two microhabitats (leaf axils of cocoyams/pineapples and leaf axils of plantain/banana) were sampled for various mosquito species. Mosquitoes were recovered from all the various biotypes sampled. Types of mosquitoes species encountered, their relative abundance, as well as genera varied significantly during the study (p<0.05). Four genera of mosquitoes: Aedes, Culex, Anopheles and Toxorhynchites were recovered while 16 species of mosquitoes encountered include: Aedes aegypti, Ae. africanus, Ae. simpsoni, Ae. albopictus, Ae. stokesi, Ae. taylori, Ae. apicoargenteus, Culex quinquefasciatus, Cx. nebulosus, Cx. trigripes, Cx. decens, Anopheles gambiae, An. funiestus, An. coustani and Toxorhynchites viridibasis. Most of the mosquitoes showed oviposition preferences for one or more habitats. The presence of Ae. africanus, Ae. simpsoni and Ae. aegypti indicate that the study areas were at risk of yellow fever epidemic. The presence of Anopheles and Culex species ensured endemicity of malaria and filariasis, while the recovery of Ae. albopictus in this region suggests a possible outbreak of dengue fever in future if not properly controlled. PMID:17655174
Anosike, Jude C; Nwoke, Bertram E B; Okere, Anthony N; Oku, Ene E; Asor, Joe E; Emmy-Egbe, Ifeyinwa O; Adimike, Desmond A
In West Africa, lineage splitting between the M and S molecular forms of the major Afro-tropical malaria mosquito, Anopheles gambiae is thought to be driven by ecological divergence, occurring mainly at the larval stage. Here, we present evidences for habitat segregation between the two molecular forms in and around irrigated rice-fields located within the humid savannahs background of western Burkina Faso. Longitudinal sampling of adult mosquitoes emerging from a range of breeding sites dist...
Gimonneau, Geoffrey; Pombi, Marco; Choisy, Marc; Morand, Serge; Dabire?, Roch K.; Simard, Frederic
Full Text Available Abstract Background The application of the Geographic Information Systems (GIS to the study of vector transmitted diseases considerably improves the management of the information obtained from the field survey and facilitates the study of the distribution patterns of the vector species. Methods As part of a study to assess remote sensing data as a tool for vector mapping, geographical features like rivers, small streams, forest, roads and residential area were digitized from the satellite images and overlaid with entomological data. Map of larval breeding habitats distribution and map of malaria transmission risk area were developed using a combination of field data, satellite image analysis and GIS technique. All digital data in the GIS were displayed in the WGS 1984 coordinate system. Six occasions of larval surveillance were also conducted to determine the species of mosquitoes, their characteristics and the abundance of habitats. Results Larval survey studies showed that anopheline and culicine larvae were collected and mapped from 79 and 67 breeding sites respectively. Breeding habitats were located at 100-400 m from human settlement. Map of villages with 400 m buffer zone visualizes that more than 80% of Anopheles maculatus s.s. immature habitats were found within the buffer zone. Conclusions This study amplifies the need for a broadening of the GIS approach which is emphasized with the aim of rejuvenating the dynamic aspect of entomological studies in Malaysia. In fact, the use of such basic GIS platforms promote a more rational basis for strategic planning and management in the control of endemic diseases at the national level.
A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the gadwall (Anas strepera). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.
Sousa, Patrick J.
A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the lesser scaup (Aythya affinis). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.
Allen, Arthur W.
We examined the ion composition of mosquito breeding sites located in the Amazon rain forest and the ion regulatory patterns of larvae from these habitats. We found larvae of Toxorhynchites haemorroidalis, Limatus durhamii, Culex (Carrollia) bonnei, and Culex (Culex) sp. residing in fallen palm bracts, leaves, and tree holes that were filled with water. These breeding sites had micromolar levels of Na(+) (1.6-99 micromol L(-1)), but K(+) and Cl(-) concentrations were higher and varied over a large range (231-17,615 micromol L(-1) K(+); 355-2,700 micromol L(-1) Cl(-)). Despite the variability in environmental ion levels and ratios, all four species maintain high hemolymph NaCl levels (80-120 mmol L(-1) Na(+); 60-80 mmol L(-1) Cl(-)). However, the species differed in the means by which they maintain hemolymph ion balance, as indicated by the range of unidirectional Na(+) and Cl(-) uptake rates. Toxorhynchites haemorroidalis had extremely low rates of Na(+) uptake and undetectable Cl(-) uptake, whereas L. durhamii had high rates of uptake for both ions. This variability in rates of uptake may reflect species differences in rates of diffusive ion loss (i.e., permeability). We observed the same curious pattern of Na(+) inhibition and Cl(-) stimulation by low-pH exposure in all four species of mosquitoes, as has been documented in other mosquitoes and aquatic insects. Kinetic analyses of Na(+) and Cl(-) uptake in C. bonnei larvae revealed an unusual pattern of Na(+) uptake that increases linearly (nonsaturable) to extremely high rates, while Cl(-) uptake is a low-affinity, low-capacity system. This pattern contrasts with L. durhamii and Culex (Culex) sp. larvae, which had large increases in both Na(+) and Cl(-) uptake when external NaCl levels were increased. Our results suggest that although these rain forest mosquito larvae are residing in habitats with similar low Na(+), high Cl(-) composition and maintain similar hemolymph NaCl levels, the underlying mechanisms of ion regulation differ among the species. PMID:12177825
Patrick, Marjorie L; Ferreira, Ruth L; Gonzalez, Richard J; Wood, Chris M; Wilson, Rod W; Bradley, Timothy J; Val, Adalberto L
Rapid population growth in Western Australia has resulted in increased development of land for residential housing, and new developments are often proposed close to water because of intrinsic aesthetic values. However, this placement may place future residents at risk of mosquito-borne disease, of which Ross River virus (RRV) disease is the most common in Australia. Mosquito dispersal data were combined with a spatial analysis of human RRV cases to show that mosquitoes dispersed readily from larval habitat into surrounding low- and high-density residential areas and that residents living within 2 km of mosquito breeding habitat had a significantly higher rate of RRV disease. This finding highlights the importance of planning authorities in state and local governments to consider the implications of mosquito-borne disease risks when assessing residential development applications. PMID:24799370
Jardine, Andrew; Neville, Peter J; Dent, Colin; Webster, Carla; Lindsay, Michael D A
Since its introduction to North America in 1987, the Asian tiger mosquito (Aedes albopictus) has spread rapidly. Due to its unique ecology and preference for container breeding sites, Ae. albopictus commonly inhabits urban/suburban areas and is often in close contact with humans. An aggressive pest, this mosquito species is a vector of multiple arboviruses. In order for mosquito control efforts to remain effective, control of this important vector must be guided by spatially explicit habitat models that aid in predicting mosquito outbreaks. Using linear regression, I determined the relationship between adult Ae. albopictus abundance and climate, census, and land use factors in nine urban/suburban study sites in central New Jersey. Systematically collected adult counts (females and males) from July to October 2008, served as estimates of abundance. Fine-scale land use/land cover data were obtained from object-oriented classifications of 2007 CIR orthophotos in Definiens eCognition. Mosquito abundance data were tested for spatial autocorrelation via Moran's I, semivariograms, and hotspot analysis in order to reveal consistent patterns in abundance. Spatial pattern analysis produced little evidence of consistent spatial autocorrelation, though several sites exhibited recurring hotspots, especially in areas near residential housing and vegetation. Stepwise multiple regression was able to explain 20-25 percent of variation in Ae. albopictus abundance at the 'backyard' or cell level and 72-78 percent of variation in abundance at the 'neighborhood' or study site level. Meteorological variables (temperature on the trap date and precipitation), census variables (vacant housing units and population density), and more detailed land use/land cover classes (deciduous woody vegetation, rights-of-way and vacant lots) were frequently selected in all eight models, though many other independent variables were included in the individual models. The results of the spatial statistics suggest that clustering may occur at a broader extent, while the superior predictive ability of the site level models over the finer grain cell level models supports this conclusion. Future work should focus on validating these models with 2009 field data and testing whether finer grain weather and census data enhance the models' predictive ability. Given the major differences between individual county models, future studies should further explore variations in Ae. albopictus habitat preferences in different geographic locations.
Full Text Available The increase in mosquito populations following extreme weather events poses a major threat to humans because of mosquitoes’ ability to carry disease-causing pathogens, particularly in low-lying, poorly drained coastal plains vulnerable to tropical cyclones. In areas with reservoirs of disease, mosquito abundance information can help to identify the areas at higher risk of disease transmission. Using a Geographic Information System (GIS, mosquito abundance is predicted across the City of Chesapeake, Virginia. The mosquito abundance model uses mosquito light trap counts, a habitat suitability model, and dynamic environmental variables (temperature and precipitation to predict the abundance of the species Culiseta melanura, as well as the combined abundance of the ephemeral species, Aedes vexans and Psorophora columbiae, for the year 2003. Remote sensing techniques were used to quantify environmental variables for a potential habitat suitability index for the mosquito species. The goal of this study was to produce an abundance model that could guide risk assessment, surveillance, and potential disease transmission. Results highlight the utility of integrating field surveillance, remote sensing for synoptic landscape habitat distributions, and dynamic environmental data for predicting mosquito vector abundance across low-lying coastal plains. Limitations of mosquito trapping and multi-source geospatial environmental data are highlighted for future spatial modeling of disease transmission risk.
A. Scott Bellows
Full Text Available The Container survey was conducted from 15th – 19th October 2013 for a period of five days in the University Campus of Chennai, Tamilnadu. The campus has an area of 175 acres (0.71 km2 and most of the main administrative buildings and faculties are located here. The surroundings of the campus have been planted with vegetation and trees, providing ideal resting sites for mosquitoes. A total of 60 containers were identified as potential breeding sites, However, more than 50% (32 containers were found containing larvae, with Tyers being the most dominant (number of containers =25, followed by plastic container (5, natural containers (2.Among all types of containers, 42% of the total surveyed Tyers were positive with mosquito larvae, followed by plastic containers (33% and natural containers (20%, especially tree holes, were the dominant breeding sites for mosquitoes in the campus. The collected mosquito larvae were Aedes aegypti (100%.
INTRODUCTION The common eider (Somateria mollissima) consists of five subspecies; four are found in North America (Palmer 1976). Six management populations of common eiders have recently been defined in eastern Canada and the United States (Reed and Erskine 1986). The American edier (S. mollissima dresseri), of which three populations are recognized (Reed and Erskine 1986), is the southernmost subspecies and the focus of this paper. The common eider is a member of the order Anseriformes, family Anatidae, and the tribe Mergini. A seabird of the northern latitudes of the world, the common eider is the largest duck of North America, ranging in weight from 1.2 to 2.8 kg and having a total length from 53.3 to 68.6 cm (Bellrose 1980). The American subspecies averages 2.0 kg and 61.0 cm for males, and 1.5 kg and 57.0 cm for females (Bellrose 1980). The drake is distinctly patterned,, having a white back and breast and a black belly and sides. The smaller female is brown and heavily barred with dark brown. Both sexes have a leathery extension of the bill which forms a Y-shaped frontal shield that reaches almost to the eyes. Maine, which supports part of the Atlantic population of common eiders (Reed and Erskine 1986), is the only major eider breeding population in the lower 48 States. American eiders are colonial nesters and use a variety of nesting sites, but they prefer relatively small, uninhabited islands (Mendall 1976). The coastal islands of Maine, which are essential to the eider's life cycle, are increasingly subjected to recreation and development, creating potential disturbances to eider breeding colonies. During recent years, aesthetic and sporting interest in eiders has increased. Sea ducks in Maine are experiencing increased hunting pressure. Compared to hunting seasons and bag limits for inland ducks, sea duck seasons and limits are liberal (Maine Department of Inland Fisheries and Wildlife [MDIFW] 1983).
Blumton, Arlene K.; Owen, Ray B., Jr.; Krohn, William B.
Full Text Available Background & objectives: A preliminary survey of larval mosquito habitats and temporal variationin mosquito diversity in the hill town of Darjeeling, India was made during 2003, for a qualitativeand quantitative assessment of mosquito distribution.Methods: The possible larval habitats of mosquitoes were surveyed and the species diversity in thesites positive for mosquito larvae was noted. Bi-weekly sampling from a particular habitat wascarried out to reveal the temporal variation in mosquito species.Results: A good number of lentic aquatic habitats were found to be hosting mosquito immatures,though difference in the physical and biological features of these habitats was prominent. Altogether,immatures of six mosquito species, belonging to four genera — Aedes, Armigeres, Culex andToxorhynchites were noted with significant difference in temporal variation in their relative andabsolute numbers. A positive correlation (r = + 0.707 was found between population of the preymosquito immatures and the population of immatures of Tx. splendens. The species diversity index(H’ for the mosquitoes remained between 0.87 and 1.53. The evenness components ranged between54.03 and 95.03% and differed significantly.Interpretation & conclusion: In the present study, the aquatic bodies could be categorised into sixtypes depending on the size and structural complexity that may account for the observed variation inthe species composition of the larval habitats. In addition to this, other factors like temperature,rainfall and other related climatic attributes may be responsible for the observed species variation,which needs to be confirmed through further studies.
Gautam Aditya,b, Mihir K. Pramanik & Goutam K. Saha
Water temperature is an important determinant of the growth and development of malaria mosquito immatures. To gain a better understanding of the daily temperature dynamics of malaria mosquito breeding sites and of the relationships between meteorological variables and water temperature, three clear water pools (diameter × depth: 0·16 × 0·04, 0·32 × 0·16 and 0·96 × 0·32 m) were created in Kenya. Continuous water temperature measurements at various depths were combined with weather da...
Paaijmans, K. P.; Jacobs, A. F. G.; Takken, W.; Heusinkveld, B. G.; Githeko, A. K.; Dicke, M.; Holtslag, A. A. M.
Understanding mosquito dispersal is critically important for vector-borne disease control and prevention. Mark–release–recapture methods using various marking techniques have made substantial contributions to the study of mosquito biology. However, the ability to mark naturally breeding mosquitoes noninvasively and with life-long retention has remained problematic. Here, we describe a method to mark naturally breeding mosquitoes with stable isotopes. Culexpipiens f. molestus mosquitoes were provisioned as larvae in laboratory experiments with 15N-labeled potassium nitrate and 13C-labeled glucose. Larval enrichment was sufficient to differentiate marked adult mosquitoes from unmarked control mosquitoes and the natural source population from Chicago Illinois, using either ?15N or ?13C. Isotopic retention lasted for at least 55 d for adult male and females mosquitoes. There were no consistent effects of isotopic enrichment on immature mosquito survival or adult mosquito body size. We then applied this marking technique to naturally breeding Culex pipiens mosquitoes in suburban Chicago, IL, and for the first time, report successful isotopic enrichment of mosquitoes in the field. This stable isotope marking technique will facilitate studies of mosquito dispersal.
HAMER, GABRIEL L.; DONOVAN, DANIELLE J.; HOOD-NOWOTNY, REBECCA; KAUFMAN, MICHAEL G.; GOLDBERG, TONY L.; WALKER, EDWARD D.
This study elucidated the relationships between larval habitat soil-substrate Organic Matter Content (OMC) and immature development of the mosquito Anopheles gambiae s.l. Day-old larvae of the mosquito were reared in media substrated with typical soil samples (i.e., sandy, silt, clayey and loamy soils), from established anopheline breeding sites, to provide a gradient in soil-substrate OMC. The OMC of the soil samples were determined by ignition to a constant weight; while the developi...
Olayemi, I. K.; Ojo, V. O.
As part of investigations on potential linkages between irrigation and malaria transmission, all surface water bodies in and around three villages along an irrigation distributary in South Punjab, Pakistan, were surveyed for anopheline mosquito larvae (Diptera: Culicidae) from April 1999 to March 2000. Samples were characterized according to exposure to sunlight, substratum, presence of vegetation, fauna, inorganic matter and physical water condition (clear/turbid/foul). Also water temperature, dissolved oxygen (DO), electroconductivity (EC) and pH of sites were recorded. A total of 37982 Anopheles larvae of six morphological types were collected from 2992 samples taken from irrigation/agricultural and village/domestic aquatic habitats. Anopheles subpictus Grassi sensu lato was by far the most abundant (74.3%), followed by An. culicifacies Giles s.l. (4.1%), An. stephensi Liston s.l. (2.6%), An. pulcherrimus Theobald (1.8%), An. peditaeniatus Leicester (0.3%) and An. nigerrimus Giles (0.1%). The four most abundant species were significantly associated with waterlogged fields and communal village drinking-water tanks. Habitat characteristics most correlated with occurrence of anophelines were the physical water condition and the absence/presence of fauna, particularly predators. Occurrence and abundance of Anopheles immatures were not significantly correlated with water temperature, DO, EC or pH. Malaria vectors of the Anopheles culicifacies complex occurred at relatively low densities, mainly in irrigated and waterlogged fields. In South Punjab, where rainfall is very low, it should be possible to reduce anopheline breeding through water management, as larvae develop mainly in water bodies that are directly or indirectly related to the extensive canal-irrigation system. PMID:11583440
Herrel, N; Amerasinghe, F P; Ensink, J; Mukhtar, M; van der Hoek, W; Konradsen, F
A survey of ground water-breeding mosquitoes was done during 1986-1987 in an area undergoing irrigation development in the Mahaweli Project of Sri Lanka. Forty-nine species were collected during the 12-mo phase of humans settlement and infrastructure construction, and 42 species during the succeeding 12-mo period under irrigated rice culture. Development resulted in the elimination of some preexisting breeding habitats, the modification of others, and the creation of new habits. The overall change from uninhabited forest to settled irrigated rice sharply increased the prevalence of Anopheles annularis van der Wulp, An. peditaeniatus (Leicester), Aedeomyia catasticta Knab, Mimomyia hybrida (Leicester), Mansonia uniformis (Theobald), and Culex tritaeniorhynchus Giles. Equally sharp decreases occurred in the prevalence of An. barbirostris van der Wulp, An. barbumbrosus Strickland & Choudhury, Ae, jamesi (Edwards), Ae. vittatus (Bigot), Ae. pseudomediofasciatus (Theobald), Cx. halifaxii Theobald, Cx. malayi (Leicester), Cx. minutissimus (Theobald), Cx. nigropunctatus Edwards, Cx. fuscocephala Theobald, and Cx. mimulus Edwards. Other species that showed smaller positive or negative changes included An. nigerrimus Giles, An. culicifacies Giles, An. jamesii Theobald, An. subpictus Grassi, An. vagus Donitz, An. varuna Iyengar, Mi. chamberlaini (Ludlow), Ma. annulifera (Theobald), Cx. bitaeniorhynchus Giles, Cx. gelidus Theobald, and Cx. pseudovishnui Colless. Irrigation development led to reduced breeding by the majority of species; however, most species that did increase in prevalence were potential vectors of human disease. Components of the irrigation system such as reservoir and canal margins, seepages, and rice fields provided increased breeding sites for some of these species. PMID:1977912
Amerasinghe, F P; Ariyasena, T G
Will mangrove encroachment into saltmarshes affect saltwater mosquito habitats? To address this, we synthesized information from two perspectives: 1) at a detailed level, the immature mosquito habitat within mangroves; 2) at a more general or regional level, changes due to mangrove expansion into saltmarshes. This is a synthesis of two research projects. One showed that mosquito larval habitats in mangroves are complex, related to the detailed interactions between topography and tidal patterns and that not all parts of a mangrove forest are suitable habitat. The other, based on remote sensing and analysis of rainfall data, showed that mangrove encroachment in eastern Australia is related to both climate and human land use over several decades (1972-2004). An important question emerged: when mangroves encroach into saltmarshes will they displace saltmarsh immature mosquito habitats or will they replace them with mangrove ones? There is no simple answer: it will vary with climate change and sea level scenario and how these affect the system. We conclude that mosquito management, which is locally implemented, needs to be integrated with land use planning systems, which often operate at a more general level. PMID:24581363
Dale, Pat; Eslami-Andargoli, Leila; Knight, Jon
Alfalfa pellets and chicken lay mash were used to obtain polluted water for continuous and sustained oviposition by Culex mosquitoes. Water in fiberglass tubs enriched with 0.1 and 0.25 percent (w/v) of either material received heavy oviposition by gravid mosquitoes. The higher level of enrichment resulted in greater oviposition than lower concentrations which in turn received significantly more oviposition than the controls with no enrichment. Oviposition continued in the enriched tubs for more than 43 days where Culex quinquefasciatus and Culex stigmatosoma constituted a major proportion of the eggs laid while Culex tarsalis, as expected, oviposited at much lower rates than the other two species. Supplemental enrichment of mosquito breeding sources with organic material can thus provide uniform and sustained availability of some mosquito larvae for the evaluation of persistent control agents and other related studies. PMID:9221736
Rodcharoen, J; Mulla, M S; Chaney, J D
A study was carried out at Mwea Rice Irrigation Scheme, Kenya, to assess the impact of rice husbandry on mosquito breeding and identify indigenous biocontrol agents with potential for controlling mosquito breeding in the scheme. The study established a close relationship between the schedule of the farming practices (particularly the flooding phase) and mosquito breeding. Two groups of agents, entomopathogenic bacteria (Bacillus thuringiensis var. israelensis) and larvivorous fish, were identified. Laboratory evaluation of the agents produced encouraging results. The bacterial isolates showed broad-spectrum larvicidal potency against Anopheles, Culex and Aedes mosquito larvae and 2 of the fish species, Tilapia zilli and Oreochromis niloticus, demonstrated a strong predation for a mosquito larval diet. To facilitate their use in effective biocontrol strategies, the agents would require further evaluation under field conditions. PMID:8096871
Asimeng, E J; Mutinga, M J
Concentrations and distribution of cadmium, chromium, copper, iron, lead, manganese and zinc in mosquito larval habitats in urban Kisumu and Malindi, Kenya and their effect on the presence of Anopheles gambiae, Aedes aegypti, Culex quinquefasciatus and Anopheles funestus larvae were investigated. Manganese and iron were the most prevalent heavy metals in water of larval habitats in urban Kisumu and Malindi, respectively. Iron was the most prevalent heavy metal in bottom sediments in larval ha...
Mireji, Paul O.; Keating, Joseph; Hassanali, Ahmed; Mbogo, Charles M.; Nyambaka, Hudson; Kahindi, Samuel; Beier, John C.
Investigations on natural antagonists of mosquito larvae found that micro-crustaceans (e.g., Cladocera) control mosquito populations under experimental conditions. However, their relevance for mosquito control under field situations remains widely unclear because important information about habitat preferences and time of occurrence of crustaceans and mosquito larvae are still missing. In order to fill this knowledge gap, a field study was undertaken in different wetland areas of Saxony, Germany, in different habitats (i.e., grassland, forest, and reed-covered wetlands). We found negative interactions between larvae of Ae. vexans and predatory Cyclopoida (Crustacean: Copepoda), which both were dominant during the first two weeks of hydroperiod, at ponds located at grassland habitats. Larvae of Cx. pipiens were spatially associated with competing Cladocera, but they colonized ponds more rapidly. Populations of Cladocera established from the third week of hydroperiod and prevented Cx. pipiens colonization thereafter. Ostracoda were highly abundant during the whole hydroperiod, but their presence was restricted to habitats of reed-covered wetland at one geographical area. Mosquito larvae hardly occurred at those ponds. In general, we found that ponds at the reed-covered wetlands provided better conditions for the initial development of crustaceans and hence, mosquito larval colonization was strongly inhibited. Grassland habitat, in contrast, favored early development of mosquito larvae. This study showed that micro-crustaceans are relevant for mosquito management but their impact on mosquito larvae varies between species and depends on environmental conditions. PMID:24820562
Kroeger, Iris; Liess, Matthias; Duquesne, Sabine
The phytoplankton specific composition and the character of its consumption by larvae of blood-sucking mosquitoes have been determined. Blue-green (5 species), green (13 species), Euglenophyta (12 species) and diatoms (38 species) algae have been found in the breeding places of Culicidae. The diatoms prevailed in the food of larvae. Trophic specialization to the definite food components have not been found in larvae. Their intestines contained detritus, zooplankton and other components besides phytoplankton. PMID:2883995
Shevchenko, A K; Stebliuk, M V; Popovich, A P
A review and synthesis of existing information were used to develop a model for evaluating the quality of habitat for breeding black-bellied whistling-ducks. The model is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimal habitat). Habitat suitability index models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service. Guidelines for model application and techniques for measuring model variable are provided.
McKenzie, Paul M.; Zwank, Phillip J.
The models I present in this dissertation were designed to enable mosquito control agencies in the mid-Atlantic region that oversee large jurisdictions to rapidly track the spatial and temporal distributions of mosquito species, especially those species known to be vectors of eastern equine encephalitis and West Nile virus. I was able to keep these models streamlined, user-friendly, and not cost-prohibitive using empirically based digital data to analyze mosquito-abundance patterns in real landscapes. This research is presented in three major chapters: (II) a series of semi-static habitat suitability indices (HSI) grounded on well-documented associations between mosquito abundance and environmental variables, (III) a dynamic model for predicting both spatial and temporal mosquito abundance based on a topographic soil moisture index and recent weather patterns, and (IV) a set of protocols laid out to aid mosquito control agencies for the use of these models. The HSIs (Chapter II) were based on relationships of mosquitoes to digital surrogates of soil moisture and vegetation characteristics. These models grouped mosquitoes species derived from similarities in habitat requirements, life-cycle type, and vector competence. Quantification of relationships was determined using multiple linear regression models. As in Chapter II, relationships between mosquito abundance and environmental factors in Chapter III were quantified using regression models. However, because this model was, in part, a function of changes in weather patterns, it enables the prediction of both 'where' and 'when' mosquito outbreaks are likely to occur. This model is distinctive among similar studies in the literature because of my use of NOAA's NEXRAD Doppler radar (3-hr precipitation accumulation data) to quantify the spatial and temporal distributions in precipitation accumulation. \\ Chapter IV is unique among the chapters in this dissertation because in lieu of presenting new research, it summarizes the preprocessing steps and analyses used in the HSIs and the dynamic, weather-based, model generated in Chapters II and III. The purpose of this chapter is to provide the reader and potential users with the necessary protocols for modeling the spatial and temporal abundances and distributions of mosquitoes, with emphasis on Culiseta melanura, in a real-world landscape of the mid-Atlantic region. This chapter also provides enhancements that could easily be incorporated into an environmentally sensitive integrated pest management program.
Bellows, Alan Scott
Anopheles aquasalis Curry is considered the main vector of human malaria in Northern Venezuela. A longitudinal study was carried out in the coastal areas of the Paria Peninsula, Sucre state. The larval habitats of A. aquasalis were classified as: 1--Brackish mangrove, and 2--Freshwater herbaceous swamp. Field surveys of mosquito larvae and aquatic insects were carried out in the same breeding sites over a one-year period, between January and December 1999. At each site, 30 samples of Anopheles larvae and aquatic insects were taken monthly. Simultaneously with mosquito larvae sampling, five selected variables of water were measured: conductivity, salinity, dissolved oxygen, temperature and pH. Seasonal and temporal variations of A. aquasalis larvae and aquatic insects were determined in the two larval habitats. For the entire study period, the abundance of larvae was higher in the mangrove. Correspondence analysis showed a strong relation between some chemical factors of water and larval abundance. The abundance of A. aquasalis larvae in both seasons, was positively correlated with water salinity, pH and conductivity, and negatively and with dissolved oxygen in the dry season. The presence of larvae was positively correlated with the presence of Avicenia germinans. In the mangrove there was a positive association between larvae abundance and Scirtidae family abundance and a negative correlation between larvae abundance and monthly precipitation (Spearman), as well as a significant negative correlation between Gerridae abundance and monthly precipitation. In the herbaceous swamp, there were not significant associations between A. aquasalis larvae abundance and abundance of others aquatic insects associated to habitat. PMID:20527475
Berti, Jesús; González, Julio; Navarro-Bueno, Edith; Zoppi, Evelin; Gordon, Elizabeth; Delgado, Laura
Research on the effects of creating group-selection openings of various sizes on breeding birds habitat use in a bottomland hardwood forest of the Upper Coastal Plain of South Carolina. Creation of 0.5-ha group selection openings in southern bottomland forests should provide breeding habitat for some field-edge species in gaps and habitat for forest-interior species and canopy-dwelling forest-edge species between gaps provided that enough mature forest is made available.
Moorman, C.E.; D.C. Guynn, Jr.
In preparation for a trial polystyrene beads and pyriproxyfen for the control of Culex quinquefasciatus mosquitoes, surveys of their breeding were carried out in two contrasting areas of Dar es Salaam, Mikocheni and Ilala, during the dry season. Sanitation structures (latrines, soakage pits, septic tanks and cess pits) were the most profilic breeding places, totalling 780 in Mikocheni and 1544 in Ilala. Those in Mikocheni were estimated to contain about 1.4 times more mosquito pupae, per site, than in such structures in Ilala. This was both because a higher proportion of sites contained visible water and because sites with water were more likely to contain pupae in Mikocheni. The relative importance of the different types of structure, in terms of productivity, was the same in both areas. Although septic tanks and cess pits made up only 10.5% of the on-site sanitation structures in Ilala, they contained 53% of the total number of pupae in enclosed sites; they were therefore particularly important targets for treatment with polystyrene beads. A survey during the rainy season of sites in Ilala revealed little change in the proportion that were wet, or in the frequency of breeding in those with visible water. The number, type and area of open breeding sites varied greatly between the two study areas. In Mikocheni the area of open breeding sites was 100 times greater than in Ilala, with 97% of the 13,000 m2 being flooded grassland. In Ilala all but four of the sixty-six open breeding sites were puddles of sullage water derived from bathrooms.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7787221
Chavasse, D C; Lines, J D; Ichimori, K; Marijani, J
Full Text Available Some physical (depth, electrical conductivity, height, surface area, temperature, volume and chemical (pH, total dissolved solids, concentrations of cadmium, calcium, chlorine, copper, magnesium, sodium, sulphate, zinc factors affecting the breeding and abundance of preimaginal mosquitoes in phytotelmata on the flamboyant tree, Delonix regia were investigated in Zaria, northern Nigeria. Forty-nine (43.36% of the 113 stands of the tree had phytotelmata while 28 (24.78% supported mosquito breeding. Of the 541 mosquito preimaginals isolated from phytotelmata were 5 (0.92% Aedes aegypti Linnaeus, 126 (23.29% Aedes metallicus Edwards, 3 (0.55% Aedes simpsoni Theobald, 79 (14.60% Culex horridus Edwards, 272 (50.28% Culex nebulosus Theobald, 52 (9.61% Culex pipiens pipiens Linnaeus and 4 (0.74% Culex tigripes Grandpre. Conspecific, congeneric, heterospecific and heterogeneric breeding behavioural patterns were observed with one, two, three and four mosquito species per phytotelma on 13 (46.43%, 11 (39.29%, 2 (7.14% and 2 (7.14% trees, respectively. Aedes genus of mosquitoes bred in phytotelmata at significantly lower heights and smaller water volumes than Culex genus (p<0.05; but depths and surface areas of phytotelmata for both genera did not differ significantly (p>0.05. Abundance of each of the seven species of mosquito correlated positively and highly significantly with water volumes in the phytotelmata (p = 0.0016; r = 0.435. Culex horridus population correlates positively and highly significantly with the concentration of cadmium (p<0.0001; r = 0.661, surface areas (p<0.05; r = 0.283 and temperature (p<0.05; r = 0.323 of water in phytotelmata. Culex nebulosus abundance correlates positively and significantly with electrical conductivity (p<0.05; r = 0.302 and total dissolved solids (p<0.05; r = 0.302 in phytotelmata. Abundance of C. p. pipiens in phytotelmata correlates positively and significantly with water depth (p<0.05; r = 0.304. The study identified some ecological factors regulating mosquito productivity in a relatively unusual larval habitat of disease vectors.
A device was developed for repetitive sampling of mosquito larvae without undue disruption of the larval habitat. The sampler is a 3-oz. (ca. 100-ml capacity) transparent plastic cup with a hole in the center of its convex bottom. The device is buoyed by corks so that the water level is 15 mm above the bottom rim of the cup and 5 mm above the hole. There was significant correlation between 24-h samples of Aedes albopictus and Culex quinquefasciatus 4th-instar larvae in the larval sampling device and populations in tires. Greater numbers of immature mosquitoes were found per unit surface area of the sampling device than the tire as a whole, demonstrating that immature mosquitoes were trapped by the sampler. PMID:8014619
Undeen, A H; Becnel, J J
Two studies in California wetlands and a third in Minnesota wetlands indicate that management practices designed to enhance habitat quality for waterfowl can concurrently reduce mosquito problems. In a seasonally flooded pickleweed wetland in Suisun Marsh, Solano Co., CA, we demonstrated that reducing plant-cover by 50% increased benthic densities of chironomid midge and dytiscid beetle larvae; these insects can be important in waterfowl diets. This manipulation also concentrated Aedes melanimon and Culiseta inornata mosquito larvae along wetland perimeters; thus, the need for control measures was greatly restricted spatially. A study in 9 experimental ponds in Suisun Marsh demonstrated that higher water levels could enhance populations of the macroinvertebrates important in waterfowl diets; general macroinvertebrate densities were higher at 60 cm depths than 20 cm or 40 cm depths. In contrast, Cs. inornata densities were lowest at 60 cm depths and highest at 20 cm depths. A study conducted in a perennial-water cattail wetland in Minneapolis-St. Paul, MN, demonstrated that a temporary water-level drawdown, designed to enhance waterfowl habitat quality of perennial-water wetlands, also reduced densities of Coquillettidia perturbans mosquito larvae. These mosquitoes disappeared immediately after the drawdown, but even after water depths were restored to pre-drawdown levels, significant numbers did not reappear until 4 years post-drawdown. Studies in 202 other Minnesota wetlands also demonstrated the susceptibility of Cq. perturbans populations to drawdown, but the impact of drawdown was greater in stands of emergent cattail than in floating cattail. PMID:1431852
Batzer, D P; Resh, V H
Abstract Background Plasmodium vivax malaria reemerged in the Republic of Korea in 1993, with more than 2,000 cases reported in the northwestern part of the country over the last 10 years. To better assess the risk of malaria transmission we conducted a surveillance study to identify and characterize the habitats that produce potential Anopheles vector mosquitoes. Immature and adult mosquito collection data were incorporated into a Geographic Information Sys...
Full Text Available Abstract Background In the past two decades the east African highlands have experienced several major malaria epidemics. Currently there is a renewed interest in exploring the possibility of anopheline larval control through environmental management or larvicide as an additional means of reducing malaria transmission in Africa. This study examined the landscape determinants of anopheline mosquito larval habitats and usefulness of remote sensing in identifying these habitats in western Kenya highlands. Methods Panchromatic aerial photos, Ikonos and Landsat Thematic Mapper 7 satellite images were acquired for a study area in Kakamega, western Kenya. Supervised classification of land-use and land-cover and visual identification of aquatic habitats were conducted. Ground survey of all aquatic habitats was conducted in the dry and rainy seasons in 2003. All habitats positive for anopheline larvae were identified. The retrieved data from the remote sensors were compared to the ground results on aquatic habitats and land-use. The probability of finding aquatic habitats and habitats with Anopheles larvae were modelled based on the digital elevation model and land-use types. Results The misclassification rate of land-cover types was 10.8% based on Ikonos imagery, 22.6% for panchromatic aerial photos and 39.2% for Landsat TM 7 imagery. The Ikonos image identified 40.6% of aquatic habitats, aerial photos identified 10.6%, and Landsate TM 7 image identified 0%. Computer models based on topographic features and land-cover information obtained from the Ikonos image yielded a misclassification rate of 20.3–22.7% for aquatic habitats, and 18.1–25.1% for anopheline-positive larval habitats. Conclusion One-metre spatial resolution Ikonos images combined with computer modelling based on topographic land-cover features are useful tools for identification of anopheline larval habitats, and they can be used to assist to malaria vector control in western Kenya highlands.
A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the blue-winged teal (Anas discors). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.
Sousa, Patrick J.
A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the bald eagle (Haliaeetus leucocephalus). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.
A review and synthesis of existing information were used to develop a model for evaluating the quality of breeding habitat for Forster's tern (Sterna forsteri). The model is applicable within the nesting range of Forster's terns along the Gulf of Mexico and Atlantic coast. It is scaled to produce an index between 0 (unsuitable habitat) and 1.0 (optimal habitat). Habitat suitability index models are designed for use with the Habitat Evaluation Procedures previously developed by the US Fish and Wildlife Service. Guidelines for model application and techniques for measuring model variables are provided.
Martin, R.P.; Zwank, P.J.
A review and synthesis of existing information were used to develop a model for evaluating the quality of habitat for breeding black-bellied whistling-ducks. The model is scaled to produce an index between 0 (unsuitable habitat) and 1.0 (optimal habitat). Habitat suitability index models are designed for use with the Habitat Evaluation Procedures previously developed by the US Fish and Wildlife Service. Guidelines for model application and techniques for measuring model variable are provided. 58 refs., 1 fig., 5 tabs.
McKenzie, P.M.; Zwank, P.J.
To classify mosquito species based on common features of their habitats, samples were obtained fortnightly between June 2001-October 2003 in the subtropical province of Chaco, Argentina. Data on the type of larval habitat, nature of the habitat (artificial or natural), size, depth, location related to sunlight, distance to the neighbouring houses, type of substrate, organic material, vegetation and algae type and their presence were collected. Data on the permanence, temperature, pH, turbidit...
Marina Stein; Francisco Ludueña-Almeida; Juana Alicia Willener; Walter Ricardo Almirón
Efficacy of a mermithid nematode Romanomermis iyengari (Welch) (Nematoda: Mermithidae) in controlling tree hole-breeding mosquito Aedes albopictus (Skuse) (Diptera: Culicidae) in a rubber plantation area of Kerala, India.
In rubber plantations, tree holes are one of the major types of breeding habitats of Aedes mosquitoes which transmit dengue and chikungunya. A mermithid nematode, Romanomermis iyengari, was evaluated in tree holes for its efficacy in controlling Aedes albopictus. Infection of mosquito larvae by the nematode was determined through microscopic examination on the next day of application, and evaluation of immature density of mosquito was done on the seventh day. After application of the infective stage of the nematode in a host-parasite ratio of 1:3 or 1:4, the infection rates on the different larval instars of mosquito were similar, 85.7-95.8 % in first to third instars and 79.3 % in fourth instar larvae or 100 and 92.9 %, respectively. Parasite burden varied from 1.1 to 2.4, respectively, among first and third instar larvae applied at 1:3. At 1:4, the parasite burden was between 1.6 (fourth instar) and 4 (second instar). The increase in parasite burden due to parasite density was significant in all the larval instars (P?rubber tree hole habitats. In the nematode-applied tree holes, there was a significant level (P?0.05) of reduction in the immature density of A. albopictus, especially late instars and pupae, confirming the efficacy of R. iyengari in infecting the mosquito and controlling pupal emergence. PMID:23306387
Paily, K P; Chandhiran, K; Vanamail, P; Kumar, N Pradeep; Jambulingam, P
Container-breeding mosquitoes, such as Aedes triseriatus, ingest biofilms and filter water column microorganisms directly to obtain the bulk of their nutrition. Scirtid beetles often co-occur with A. triseriatus and may facilitate the production of mosquito adults under low-resource conditions. Using molecular genetic techniques and quantitative assays, we observed changes in the dynamics and composition of bacterial and fungal communities present on leaf detritus and in the water column when...
Pelz-stelinski, Kirsten; Kaufman, Michael G.; Walker, Edward D.
Highlights: ? An assessment of different household wastes as larval habitats of dengue vectors Aedes aegypti and Aedes albopictus was made using Kolkata, India as a model geographical area. ? Household wastes of four major categories namely earthen, porcelain, plastic and coconut shells varied significantly for Aedes immature depending on species, month and location. ? Based on the relative density of Aedes immature, cluster analyses allowed segregation and classification of the waste containers and relative importance as mosquito larval habitats. ? Conversion of disposed wastes into larval habitats cautions for continuance of Aedes population in Kolkata and similar cities of tropics lacking suitable waste management practices. - Abstract: An assessment of the household wastes as larval habitats of the dengue vectors was made considering Kolkata, India, as geographical area. Wastes of four major categories, namely, earthen, porcelain, plastic and coconut shells were monitored for positive with immature of either Aedes aegypti or Aedes albopictus. Twenty six types of wastes with varying size and shape, resembling containers, were identified that hosted mosquito immature. The number of waste containers positive for Aedes immature varied significantly (P < 0.05) with respect to location, type and month. The relative density of Aedes immature in the waste containers varied significantly (P < 0.05) with the types and months. The significant interaction between the month, waste container types and density of Aedes immature suggest that the household wastes are important contributors to the maintenance of the population of Aedes mosquito in the city. Based on the relative density of mosquito immature in the wastes, cluster analysis allowed segregation and classification of the wastes and their importance as mosquito larval habitats. Apparently, the containers that are most frequently disposed off contributed largely to the sustenance of Aedes mosquito population in the city. This calls for a strict legislation towards disposal as well as enhanced management of the household wastes. A link between the wastes disposed and subsequent conversion to the mosquito larval habitats cautions for continuance of Aedes population and possibility of dengue epidemics if the existing management practices are not improved.
Highlights: Black-Right-Pointing-Pointer An assessment of different household wastes as larval habitats of dengue vectors Aedes aegypti and Aedes albopictus was made using Kolkata, India as a model geographical area. Black-Right-Pointing-Pointer Household wastes of four major categories namely earthen, porcelain, plastic and coconut shells varied significantly for Aedes immature depending on species, month and location. Black-Right-Pointing-Pointer Based on the relative density of Aedes immature, cluster analyses allowed segregation and classification of the waste containers and relative importance as mosquito larval habitats. Black-Right-Pointing-Pointer Conversion of disposed wastes into larval habitats cautions for continuance of Aedes population in Kolkata and similar cities of tropics lacking suitable waste management practices. - Abstract: An assessment of the household wastes as larval habitats of the dengue vectors was made considering Kolkata, India, as geographical area. Wastes of four major categories, namely, earthen, porcelain, plastic and coconut shells were monitored for positive with immature of either Aedes aegypti or Aedes albopictus. Twenty six types of wastes with varying size and shape, resembling containers, were identified that hosted mosquito immature. The number of waste containers positive for Aedes immature varied significantly (P < 0.05) with respect to location, type and month. The relative density of Aedes immature in the waste containers varied significantly (P < 0.05) with the types and months. The significant interaction between the month, waste container types and density of Aedes immature suggest that the household wastes are important contributors to the maintenance of the population of Aedes mosquito in the city. Based on the relative density of mosquito immature in the wastes, cluster analysis allowed segregation and classification of the wastes and their importance as mosquito larval habitats. Apparently, the containers that are most frequently disposed off contributed largely to the sustenance of Aedes mosquito population in the city. This calls for a strict legislation towards disposal as well as enhanced management of the household wastes. A link between the wastes disposed and subsequent conversion to the mosquito larval habitats cautions for continuance of Aedes population and possibility of dengue epidemics if the existing management practices are not improved.
Banerjee, Soumyajit, E-mail: email@example.com [Department of Zoology, University of Calcutta, 35 Ballygunge Circular Road, Kolkata 700 019 (India); Aditya, Gautam, E-mail: firstname.lastname@example.org [Department of Zoology, University of Calcutta, 35 Ballygunge Circular Road, Kolkata 700 019 (India); Department of Zoology, The University of Burdwan, Golapbag, Burdwan 713 104 (India); Saha, Goutam K, E-mail: email@example.com [Department of Zoology, University of Calcutta, 35 Ballygunge Circular Road, Kolkata 700 019 (India)
Background: Ecological data are important in the vector control management of mosquitoes. There is scattered published information about the larval habitat characteristics and ecology of the genus Anopheles (Diptera: Culicidae) in Iran and most of available data is in relation to malaria vectors in southern Iran.Methods: This cross sectional investigation was carried out to study the mosquito fauna and ecology in Guilan Province, northern Iran, during April–December 2000. Larvae were coll...
Full Text Available Abstract Background Agricultural practices such as the use of irrigation during rice cultivation, the use of ponds for fish farming and the storage of water in tanks for livestock provide suitable breeding grounds for anthropophylic mosquitoes. The most common anthropophylic mosquito in Nigeria which causes much of the morbidity and mortality associated with malaria is the anopheles mosquito. Farmers are therefore at high risk of malaria - a disease which seriously impacts on agricultural productivity. Unfortunately information relating to agricultural practices and farmers' behavioural antecedent factors that could assist malaria programmers plan and implement interventions to reduce risk of infections among farmers is scanty. Farmers' knowledge about malaria and agricultural practices which favour the breeding of mosquitoes in Fashola and Soku, two rural farming communities in Oyo State were therefore assessed in two rural farming communities in Oyo State. Methods This descriptive cross-sectional study involved the collection of data through the use of eight Focus Group Discussions (FGDs and the interview of 403 randomly selected farmers using semi-structured questionnaires. These sets of information were supplemented with observations of agricultural practices made in 40 randomly selected farms. The FGD data were recorded on audio-tapes, transcribed and subjected to content analysis while the quantitative data were analyzed using descriptive and inferential statistics. Results Most respondents in the two communities had low level of knowledge of malaria causation as only 12.4% stated that mosquito bite could transmit the disease. Less than half (46.7% correctly mentioned the signs and symptoms of malaria as high body temperature, body pains, headache, body weakness and cold/fever. The reported main methods for preventing mosquito bites in the farming communities included removal of heaps of cassava tuber peelings (62.3%, bush burning/clearing (54.6% and clearing of ditches (33.7%. The dumping of cassava tuber peelings which allows the collection of pools of water in the farms storage of peeled cassava tubers soaked in water in uncovered plastic containers, digging of trenches, irrigation of farms and the presence of fish ponds were the observed major agricultural practices that favoured mosquito breeding on the farms. A significant association was observed between respondents' knowledge about malaria and agricultural practices which promote mosquito breeding. Respondents' wealth quintile level was also seen to be associated with respondents' knowledge about malaria and agricultural practices which promote mosquito breeding. Conclusion Farmers' knowledge of malaria causation and signs and symptoms was low, while agricultural practices which favour mosquito breeding in the farming communities were common. There is an urgent need to engage farmers in meaningful dialogue on malaria reduction initiatives including the modification of agricultural practices which favour mosquito breeding. Multiple intervention strategies are needed to tackle the factors related to malaria prevalence and mosquito abundance in the communities.
Oshiname Frederick O
A standardized larval dipping method was used to determine the infestation rates of Culex and other species of mosquitoes in stagnant water at 20 residential areas. This study also examined the associations between Culex distribution and various habitat characteristics across all states in Malaysia. Identification of 7,848 specimens yielded 6 species dominated by Culex quinquefasciatus (82.74%), followed by Cx. vishui (14.39%), Cx. gelidus (2.70%), Lutzia fuscanus (0.11%), Armigeres subalbatus (0.05%), and Anopheles separatus (0.01%). The Culex larvae occurred in stagnant water with pH ranging from 6.4 to 8.2; conductivity, 139.7 to 6635.2 micros/cm; salinity, 0.07 to 3.64 ppt; total dissolved solids, 0.09 to 4.27g/liter; and dissolved oxygen, 5.11 to 8.11 mg/liter. The mean number of Culex larvae was positively correlated with pH, conductivity, salinity, and total dissolved solids. In contrast, the elevation and dissolved oxygen were found negatively correlated with mean number of Culex larvae. This study documented baseline information on the habitat characteristics of Culex species for the 1st time at different residential areas in Malaysia. The findings of this study will be a timely reminder to local authorities that effective control measures should be monitored regularly in order to reduce the nuisance of these mosquitoes and the risks of disease transmission. PMID:23833895
Low, Van Lun; Chen, Chee Dhang; Lee, Han Lim; Lim, Phaik Eem; Leong, Cherng Shii; Sofian-Azirun, Mohd
Recently, in several areas of the Middle East, a sharp increase of cutaneous leishmaniasis was observed in suburbs of larger towns including Jerusalem. In some of these areas, poor housing conditions and unsuitable waste management was suspected to provide ideal conditions for sand fly breeding, but hard data on diurnal resting sites and breeding habitats of most sand fly species are scant. In this study, we chose 16 sites on both slopes and the bottom of a natural valley in the Judean Desert to conduct a survey of sand fly distribution with emergence traps. Altogether, 1,261 sand flies, 52%Phlebotomus syriacus, 22%P. sergenti, 14%P. papatasi and 12%P. tobbi were caught. About two thirds of the flies caught were resting, while the other third emerged from breeding sites. All four species showed clear preferences for resting and breeding sites, but generally, most sand flies were breeding in the more humid habitats, namely the bottom of the valley, the adjacent north facing slope, terraces on the north facing slope, and caves. The vegetation cover also appeared to be important for resting habitats; on the bottom of the valley more than six times as many sand flies were collected in areas covered by dense vegetation than in areas with low vegetation cover. P. sergenti seemed also to better tolerate the drier habitats, which might explain the abundance of this species in the arid Judean Desert. PMID:21366775
Müller, Günter C; Kravchenko, Vasiliy D; Rybalov, Leonid; Schlein, Yosef
Full Text Available Analysing companion species from unrelated taxa concentrated so far mainly on identifying biosurrogacy in terms ofconservation biology. No study has investigated companion bird and plant species to predict breeding and migranthabitats of a bird genus. In this study we recorded and analysed companion bird and plant species of the breeding birdCyprus Wheatear Oenanthe cypriaca and four migranting Oenanthe species on Cyprus. We found characteristic companionspecies in Cyprus Wheatear’s, Wheatear migrant’s and in control habitats where no Wheatears were present.We show that plant and bird companion species can be used as discriminating factors to predict breeding and migranthabitats of the genus Oenanthe on Cyprus. Furthermore, habitat preferences of Cyprus Wheatear’s companion speciesindicate bushy and vegetation rich habitats avoiding woodland on the one hand and managed farmland on the otherhand. In comparison, migrant Wheatear and control habitats were characterised by companion species pointing to ahigh openness. These results support former habitat descriptions of Cyprus Wheatear and migrant Wheatears. In moregeneral, this study shows that companion species from unrelated taxa can be used to predict breeding and migranthabitats of a bird genus.
Full Text Available Landscape and biotopic characteristics of some Sivash islands are presented. The principal role of these factors forthe support of the bird species diversity is proved. It is suggested that the islands’ genesis determines the dominantvegetation and the breeding habitats for the birds. Two types of islands – accumulative and continental are considered.
Matsyura O. V.
Full Text Available Understanding the temporal and spatial scale at which habitat alteration impacts populations is important for conservation and management. Amphibians have declined more than other vertebrates, and pond-breeding species are particularly susceptible to habitat loss and fragmentation because they have terrestrial and aquatic life stages. One approach to management of pond-breeding species is protection of core upland habitat surrounding the breeding pond. We used genetic variation as an indicator of population status in a common amphibian species, spotted salamanders (Ambystoma maculatum, to determine how amount of suitable upland habitat relates to population status in the greater Charlotte, North Carolina, USA metropolitan area. We developed candidate models to evaluate the relative influence of historical and contemporary forested habitat availability on population genetic variation at two spatial scales of upland area (164 m and 2000 m at four time intervals over the past seven decades (1938, 1978, 1993, 2005. We found that historical land cover best predicted contemporary allelic richness. Inbreeding coefficient and observed heterozygosity were not effectively predicted by forest cover at either spatial or temporal scales. Allelic richness was best predicted at the smaller spatial scale in the 1993 time interval. Predicting and understanding how future landscape configuration affects genetic variation of common and rare species is imperative for the conservation of amphibian and other wildlife populations.
Jeremiah R. Alexander
Background Since its first detection in 2001, West Nile Virus (WNV) poses a significant health risk for residents of Shelby County in Tennessee. This situation forced public health officials to adopt efficient methods for monitoring disease spread and predicting future outbreaks. Analyses that use environmental variables to find suitable habitats for WNV-infected mosquitoes have the potential to support these efforts. Using the Mahalanobis Distance statistic, we identified areas of Shelby County that are ecologically most suitable for sustaining WNV, based on similarity of environmental characteristics to areas where WNV was found. The environmental characteristics in this study were based on Geographic Information Systems (GIS) data, such as elevation, slope, land use, vegetation density, temperature, and precipitation. Results Our analyses produced maps of likely habitats of WNV-infected mosquitoes for each week of August 2004, revealing the areas that are ecologically most suitable for sustaining WNV within the core of the Memphis urban area. By comparing neighbourhood social characteristics to the environmental factors that contribute to WNV infection, potential social drivers of WNV transmission were revealed in Shelby County. Results show that human population characteristics and housing conditions such as a high percentage of black population, low income, high rental occupation, old structures, and vacant housing are associated with the focal area of WNV identified for each week of the study period. Conclusion We demonstrated that use of the Mahalanobis Distance statistic as a similarity index to assess environmental characteristics is a potential raster-based approach to identify areas ecologically most suitable for sustaining the virus. This approach was also useful to monitor changes over time for likely locations of infected mosquito habitats. This technique is very helpful for authorities when making decisions related to an integrated mosquito management plan and targeted health education outreach.
Ozdenerol, Esra; Bialkowska-Jelinska, Elzbieta; Taff, Gregory N
The epidemiology of malaria is largely dependent on its vector habitat. Each species of Anopheles larvae has a specific habitat requirement for its development. Anopheline mosquitoes are common throughout Thailand and utilize a wide variety of habitats. The dominant malaria vectors in Thailand are An. dirus, An. maculatus, and An. minimus. The relationship between soil chemical components and the particular species of anopheline in their specific aquatic habitats was studied from September 2002 to July 2003 at Ban Khun Huay, Ban Pa Dae, and Ban Tham Seau in the Mae Sot district, Tak Province, Thailand. Mapping of each habitat was performed using a Global Positioning System unit. A total count of 2,130 laboratory reared adult Anopheles were collected from 138 habitats categorized into 11 different types identified into 18 species from larval sampling in three villages. An. dirus, An. maculatus, and An. minimus were found 5.26%, 10.70%, and 55.31%, respectively, along with other minor species. Drainage and/or season seemed to be associated with the presence of An. dirus, An. maculatus, An. minimus, An. jamesii, An. sawadwongporni, and An. peditaeniatus. Chemical tests: pH, aluminum, magnesium, calcium, and ferric iron showed some associations with the presence of Anopheles. Only drainage was found to be a parameter associated with the presence of An. minimus. PMID:16438140
Kankaew, Prasan; Krasaesub, Somporn; Sithiprasasna, Ratana
Habitat use has important consequences for avian reproductive success and survival. In coastal areas with recreational activity, human disturbance may limit use of otherwise suitable habitat. Snowy plovers Charadrius nivosus have a patchy breeding distribution along the coastal areas on the Florida Panhandle, USA. Our goal was to determine the relative effects of seasonal human disturbance and habitat requirements on snowy plover habitat use. We surveyed 303 sites for snowy plovers, human dis...
Webber, Alyson F.; Heath, Julie A.; Fischer, Richard A.
Full Text Available We investigated home-range characteristics and habitat selection by Black-backed Woodpeckers (Picoides arcticus in an unburned, boreal forest landscape managed by mosaic harvesting in Quebec, Canada. Habitat selection by this species was specifically examined to determine home-range establishment and foraging activities. We hypothesized that Black-backed Woodpeckers would respond to harvesting by adjusting their home-range size as a function of the amount of dead wood available. Twenty-two birds were tracked using radiotelemetry, and reliable estimates of home-range size were obtained for seven breeding individuals (six males and one female. The average home-range size was 151.5 ± 18.8 ha (range: 100.4–256.4 ha. Our results indicate that this species establishes home ranges in areas where both open and forested habitats are available. However, during foraging activities, individuals preferentially selected areas dominated by old coniferous stands. The study also showed that the spatial distribution of preferred foraging habitat patches influenced space use, with home-range area increasing with the median distance between old coniferous habitat patches available within the landscape. Finally, these data show that Black-backed Woodpeckers may successfully breed in an unburned forest with at least 35 m3 ? ha-1 of dead wood, of which 42% (15 m3 ? ha-1 is represented by dead wood at the early decay stage.
Junior A. Tremblay
Mortality of American white pelican (Pelecanus erythrorhynchos) chicks attributed to West Nile virus (WNV) prompted field studies on the bionomics of mosquitoes on a wildlife refuge in northern Montana. One component of these studies was to identify blood meal sources for Culex tarsalis, the primary vector of WNV in the region, and the potential bridge vectors Aedes vexans and Culiseta inornata. To accomplish this, 3 methods were evaluated to collect bloodfed mosquitoes: a gasoline powered aspirator, CO2-baited light traps, and fiber pots in shelterbelts consisting of stands of deciduous trees and shrubs and marshes along the lake edge. Fiber pots were also deployed in open fields of prairie grasses. Overall, fiber pots were the most efficient method for collecting engorged Cx. tarsalis and Cs. inornata, largely due to shorter sampling and processing times. Aedes vexans was not collected in fiber pots but was more abundant in aspiration samples than the other 2 species. The optimal location for collecting Cx. tarsalis was dependent on trapping method. Aspirations and fiber pot placements collected more Cx. tarsalis in shelterbelts, while CO2-baited light traps collected more Cx. tarsalis in the marsh habitat. Sixteen avian and 4 mammalian hosts were identified from bloodfed Cx. tarsalis with 46 blood meals derived from birds and 49 from mammals. Aedes vexans and Cs. inornata fed predominantly on white-tailed deer (Odocoileus virginianus) and cattle (Bos taurus), respectively. Humans were identified as hosts in 33% of engorged Cx. tarsalis, 4% of engorged Ae. vexans, and 18% of engorged Cs. inornata. PMID:23923324
Friesen, Kristina M; Johnson, Gregory D
Mosquito breeding in relation to aquatic vegetation and certain physico-chemical parameters was studied in rice fields of Kheda district in central Gujarat. A total of 14 anopheline and 15 culicine species were encountered in close association with different types of aquatic vegetation in different proportions. Among anophelines, Anopheles annularis, An. nigerrimus, An. subpictus and An. tessellatus were of general distribution and were found associated with each aquatic vegetation. An. culicifacies showed poor association with most of the aquatic weeds. Maximum number of anophelines were found associated with algae. Culex vishnui sub-group predominated among culicines and showed frequent association with Ceratophyllum, Hydrilla and algae. Physico-chemical parameters also exerted some impact on mosquito larval population. PMID:8690130
Kant, R; Pandey, S D; Sharma, S K
During a short survey of soil and mosquito breeding sites in Lucknow, India for potential mycopathogen from a period of August-October 1996, 11 species of fungi in 5 genera were isolated using live mosquito larvae as host, Aspergillus flavus, A. fumigatus and Fusarium semitectum were the most frequently isolated species. Other fungi recorded were A. niger, A. ochraceus, A. terreus, A. versicolor, Geotrichum candidum, Penicillium verrucosum, Paecilomyces sp. and Fusarium sp. (Liseola/Elegans complex). Insect cell walls are known to contain chitin, so fungal isolates were tested for their chitinase activity on semi synthetic medium containing colloidal chitin. High chitinolytic activities were observed with A. flavus and A. ochraceus. Chitinase producers can be considered as potential pathogens. However, the higher incidence of F. semitectum could not be explained by inability to utilize chitin. PMID:10481288
Sur, B; Bihari, V; Sharma, A; Basu, S K
Abstract Background Mosquitoes commute between blood-meal hosts and water. Thus, heterogeneity in human biting reflects underlying spatial heterogeneity in the distribution and suitability of larval habitat as well as inherent differences in the attractiveness, suitability and distribution of blood-meal hosts. One of the possible strategies of malaria control is to identify local vector species and then attack water bodies that contain their larvae. Methods Biti...
Menach Arnaud; Ellis, Mckenzie F.; Flahault Antoine; Smith David L
The aquatic insect fauna of salt marshes is poorly characterized, with the possible exception of biting Diptera. Aquatic insects play a vital role in salt marsh ecology, and have great potential importance as biological indicators for assessing marsh health. In addition, they may be impacted by measures to control mosquitoes such as changes to the marsh habitat, altered hydrology, or the application of pesticides. Given these concerns, the goals of this study were to conduct the first taxonom...
Rochlin, Ilia; Dempsey, Mary E.; Iwanejko, Tom; Ninivaggi, Dominick V.
The aim of this study was to determine whether remotely sensed data could be used to identify rice-related malaria vector breeding habitats in an irrigated rice growing area near Niono, Mali. Early stages of rice growth show peak larval production, but Landsat sensor data are often obstructed by clouds during the early part of the cropping cycle (rainy season). In this study, we examined whether a classification based on two Landsat Enhanced Thematic Mapper (ETM)+ scenes acquired in the middl...
Diuk-wasser, M. A.; Bagayoko, M.; Sogoba, N.; Dolo, G.; Toure?, M. B.; Traore?, S. F.; Taylor, C. E.
Models of ecological speciation predict that certain types of habitat should be more conducive to species diversification than others. In this study, I test this hypothesis in waders of the sub-order Charadrii using the number of morphological sub-species per species as an index of diversity. I classified all members of this clade as spending the non-breeding season either coastally or inland and argue that these represent fundamentally different environments. Coastal mudflats are characteris...
The increase in mosquito populations following extreme weather events poses a major threat to humans because of mosquitoes’ ability to carry disease-causing pathogens, particularly in low-lying, poorly drained coastal plains vulnerable to tropical cyclones. In areas with reservoirs of disease, mosquito abundance information can help to identify the areas at higher risk of disease transmission. Using a Geographic Information System (GIS), mosquito abundance is predicted across the City of Ch...
Cleckner, Haley L.; Allen, Thomas R.; Scott Bellows, A.
We carried out a primary survey by quadrat sampling to quantify breeding habitat characteristics of blackthroat (Luscnia obscura), a poorly documented and vulnerable bird species, in Foping nature reserve on the central southern Qinling Mountains. Tree layer information was collected in 10 m × 10 m plots, bamboo and shrub layer information was collected in 2 m × 2 m plots, and grass and ground layer information was collected in 1 m × 1 m plots. Our observations showed that blackthroat lives in coniferous forest and coniferous broadleaved forest with dense bamboos at the elevation ranging from 2130 m to 2600 m. Shrub cover, density and height, and ground cover in sites with blackthroat were significantly higher than those in random sites, while tree density, grass height and cover in habitat sites were significantly lower than those in random sites. These results suggest that shrub cover, shrub density, and canopy cover may be relevant to breeding habitat selection by these birds. Our study suggests that Qinling Mountains may be an important blackthroat breeding site. PMID:24832900
Zhao, Hongfeng; Han, Ning; Luo, Lei; Zhao, Leigang; Gao, Xuebin
Full Text Available We used ground surveys to identify breeding habitat for Whimbrel (Numenius phaeopus in the outer Mackenzie Delta, Northwest Territories, and to test the value of high-resolution IKONOS imagery for mapping additional breeding habitat in the Delta. During ground surveys, we found Whimbrel nests (n = 28 in extensive areas of wet-sedge low-centered polygon (LCP habitat on two islands in the Delta (Taglu and Fish islands in 2006 and 2007. Supervised classification using spectral analysis of IKONOS imagery successfully identified additional areas of wet-sedge habitat in the region. However, ground surveys to test this classification found that many areas of wet-sedge habitat had dense shrubs, no standing water, and/or lacked polygon structure and did not support breeding Whimbrel. Visual examination of the IKONOS imagery was necessary to determine which areas exhibited LCP structure. Much lower densities of nesting Whimbrel were also found in upland habitats near wetlands. We used habitat maps developed from a combination of methods, to perform scenario analyses to estimate the potential effects of the Mackenzie Gas Project on Whimbrel habitat. Assuming effective complete habitat loss within 20 m, 50 m, or 250 m of any infrastructure or pipeline, the currently proposed pipeline development would result in loss of 8%, 12%, or 30% of existing Whimbrel habitat. If subsidence were to occur, most Whimbrel habitat could become unsuitable. If the facility is developed, follow-up surveys will be required to test these models.
Lisa D. Pirie
/ An integrated management plan to create favorable nesting habitat for the world-endangered Dalmatian pelicans, was tested at Kerkini irrigation reservoir, a Ramsar wetland. The lake is the major wintering site of Dalmatian pelicans in Europe, where the species lives year-round without breeding. The rise of water level at the reservoir during spring (exceeding 5 m) has an impact on the whole system, including several birds, which lose their nesting habitat. Although the integrity of the wetland demands ecological restoration with changes in its hydrologic regime, local socioeconomic conditions allow only habitat level interventions. During the planning phase of the management plan, both the ecological and social context of the interventions were considered. Monitoring of all pelican habitats and populations provided the scientific basis, while a socioecological survey on knowledge/attitudes of local fishermen toward wetland identified conflicts with specific resources and planned management. To gain public support, a broad information/education program was implemented. The education program for fishermen was based on the findings of the socioecological survey. The in situ management involved experimental construction of floating rafts, platforms over water, dredged-spoil islands, and platforms at various sites of the wetland. Monitoring of the managed habitats showed that most waterbirds used them for resting and roosting. Common terns nested on the rafts, cormorants on the platforms, and Dalmatian pelicans on the man-made island. Under the prevailing hydrologic and weather conditions, islands seem to be the most suitable habitat for pelican nesting. It is concluded that wildlife habitat management should integrate the ecological component, related to the needs of the species and ecosystem, with the social one, expressed by cooperation and involvement of the local community.KEY WORDS: Integrated management; Pelican; Nesting habitat; Habitat management; Reservoir-wetland; Public participation, Greece PMID:9236282
Full Text Available Background: Community participation plays an important role in control of Mosquito borne diseases. This study tries to assess impact of educational intervention on various aspects of mosquito borne diseases in an urban slum. Methodology: An educational interventional study was done in 200 families residing in a slum (Badi Gwaltoli which is in field practice area of Urban Health Centre attached to Department of Community Medicine of M.G.M.Medical College, Indore. A pretested semi-structured questionnaire was administered to the Head of the family which studied their awareness and perception regarding breeding sites and biting habits of mosquitoes, diseases spread by them and personal protective measures used, followed by an educational intervention and post assessment. Data was entered into Microsoft excel spread sheet and analysed using SPSS version 20 software. Results: 46% of study population knew the correct breeding season of mosquitoes (monsoon season during pre-intervention and 68% of the population post- intervention (p- value 0.004. When asked at what time mosquitoes bite the most, maximum number (92% of people said that mosquitoes bite most in the evening and night, while only 6% and 2% were for morning and noon, respectively. Only 3.5% of the population who knew about breeding sites knew about artificial collections of water. Majority said mosquito breed in dirty stagnant water (78.5%. About 96%of the study population was aware that mosquitoes spread diseases. However, only 33.3%of respondents knew correctly about the diseases spread which improved to 68% in the post-intervention period (p-value=.000. 46% knew all the protection measures against mosquitoes in the pre-intervention which increased to 86% in the post intervention (p.value-.005. Conclusion: Awareness about Aedes mosquitoes and its habits is quite poor and many people still believe that only dirty water serves as a breeding place in mosquitoes. Regular IEC sessions informing community about mosquito-borne diseases will improve community participation.
Sand flies belonging to the genus Sergentomyia Franca & Parrot, 1920, are hematophagous insects feeding mostly on reptiles and birds, but some species feed also on mammals including humans. Sergentomyia spp. frequently comprise the vast majority of sand flies trapped along with Phlebotomus spp., the vectors of mammalian leishmaniasis. Within the framework of a project on the ecology and transmission of visceral leishmaniasis in Ethiopia, putative breeding sites of phlebotomine sand flies were studied. Large horizontal sticky traps (LHSTs) covered with sand fly-proof mesh were deployed over cracked vertisol and related habitats for up to 3 nights, and emerging sand flies were collected daily. Emergence traps (ETs) were also adapted to sample other putative breeding sites including tree trunks, termite mounds, rock piles and vertical river banks. Productive breeding sites were identified in the trunks and roots systems of trees, vertisol fields, cracks and burrows in vertisol dry river banks and termite mounds. Emerging flies were also collected form a stone wall and a rock pile situated inside a village. Significantly more Sergentomyia spp. were trapped in vertisols by ETs deployed over root system than in open fields. Similarly, more sand flies emerged from cracks in the vertisol in fallow Sorghum than in fallow sesame fields. Productive breeding sites were characterized by stable micro-climatic conditions. Species composition of emerging sand flies varied with habitat, season and geographical location. PMID:24841132
Moncaz, Aviad; Kirstein, Oscar; Gebresellassie, Araya; Lemma, Wossenseged; Gebre-Michael, Teshome; Balkew, Meshesha; Belay, Shewaye; Hailu, Asrat; Warburg, Alon
Full Text Available To classify mosquito species based on common features of their habitats, samples were obtained fortnightly between June 2001-October 2003 in the subtropical province of Chaco, Argentina. Data on the type of larval habitat, nature of the habitat (artificial or natural, size, depth, location related to sunlight, distance to the neighbouring houses, type of substrate, organic material, vegetation and algae type and their presence were collected. Data on the permanence, temperature, pH, turbidity, colour, odour and movement of the larval habitat's water were also collected. From the cluster analysis, three groups of species associated by their degree of habitat similarity were obtained and are listed below. Group 1 consisted of Aedes aegypti. Group 2 consisted of Culex imitator, Culex davisi, Wyeomyia muehlensi and Toxorhynchites haemorrhoidalis separatus. Within group 3, two subgroups are distinguished: A (Psorophora ferox, Psorophora cyanescens, Psorophora varinervis, Psorophora confinnis, Psorophora cingulata, Ochlerotatus hastatus-oligopistus, Ochlerotatus serratus, Ochlerotatus scapularis, Culex intrincatus, Culex quinquefasciatus, Culex pilosus, Ochlerotatus albifasciatus, Culex bidens and B (Culex maxi, Culex eduardoi, Culex chidesteri, Uranotaenia lowii, Uranotaenia pulcherrima, Anopheles neomaculipalpus, Anopheles triannulatus, Anopheles albitarsis, Uranotaenia apicalis, Mansonia humeralis and Aedeomyia squamipennis. Principal component analysis indicates that the size of the larval habitats and the presence of aquatic vegetation are the main characteristics that explain the variation among different species. In contrast, water permanence is second in importance. Water temperature, pH and the type of larval habitat are less important in explaining the clustering of species.
To classify mosquito species based on common features of their habitats, samples were obtained fortnightly between June 2001-October 2003 in the subtropical province of Chaco, Argentina. Data on the type of larval habitat, nature of the habitat (artificial or natural), size, depth, location related to sunlight, distance to the neighbouring houses, type of substrate, organic material, vegetation and algae type and their presence were collected. Data on the permanence, temperature, pH, turbidity, colour, odour and movement of the larval habitat's water were also collected. From the cluster analysis, three groups of species associated by their degree of habitat similarity were obtained and are listed below. Group 1 consisted of Aedes aegypti. Group 2 consisted of Culex imitator, Culex davisi, Wyeomyia muehlensi and Toxorhynchites haemorrhoidalis separatus. Within group 3, two subgroups are distinguished: A (Psorophora ferox, Psorophora cyanescens, Psorophora varinervis, Psorophora confinnis, Psorophora cingulata, Ochlerotatus hastatus-oligopistus, Ochlerotatus serratus, Ochlerotatus scapularis, Culex intrincatus, Culex quinquefasciatus, Culex pilosus, Ochlerotatus albifasciatus, Culex bidens) and B (Culex maxi, Culex eduardoi, Culex chidesteri, Uranotaenia lowii, Uranotaenia pulcherrima, Anopheles neomaculipalpus, Anopheles triannulatus, Anopheles albitarsis, Uranotaenia apicalis, Mansonia humeralis and Aedeomyia squamipennis). Principal component analysis indicates that the size of the larval habitats and the presence of aquatic vegetation are the main characteristics that explain the variation among different species. In contrast, water permanence is second in importance. Water temperature, pH and the type of larval habitat are less important in explaining the clustering of species. PMID:21739026
Stein, Marina; Ludueña-Almeida, Francisco; Willener, Juana Alicia; Almirón, Walter Ricardo
Full Text Available Abstract Background This study characterized Anopheles mosquito larval habitats in relation to ecological attributes about the habitat and community-level drainage potential, and investigated whether agricultural activities within or around urban households increased the probability of water body occurrence. Malindi, a city on the coast of Kenya, was mapped using global positioning system (GPS technology, and a geographic information system (GIS was used to overlay a measured grid, which served as a sampling frame. Grid cells were stratified according to the level of drainage in the area, and 50 cells were randomly selected for the study. Cross-sectional household and entomological surveys were conducted during November and December 2002 within the 50 grid cells. Chi-square analysis was used to test whether water bodies differed fundamentally between well and poorly drained areas, and multi-level logistic regression was used to test whether household-level agricultural activity increased the probability of water body occurrence in the grid cell. Results Interviews were conducted with one adult in 629 households. A total of 29 water bodies were identified within the sampled areas. This study found that characteristics of water bodies were fundamentally the same in well and poorly drained areas. This study also demonstrated that household-level urban agriculture was not associated with the occurrence of water bodies in the grid cell, after controlling for potential confounders associated with distance to the city center, drainage, access to resources, and population density. Conclusions Household-level urban agricultural activity may be less important than the other types of human perturbation in terms of mosquito larval habitat creation. The fact that many larvae were coming from few sites, and few sites in general were found under relatively dry conditions suggests that mosquito habitat reduction is a reasonable and attainable goal in Malindi.
Changes in habitat suitable for breeding of two sympatric raptor species (Haliaeetus albicilla and Aquila pomarina) were analysed along one of the most important breeding sites in Croatia for both species. The habitat suitability modelling was used to assess the influence of forestry practice during 2000-2006 using the known data on nesting places along research area. The four most important variables for lesser spotted eagle were elevation, distance from the nearest pasture, vertical distance to the nearest channel network and broadleaved forest placement (second axis from the principal component analysis of the enhanced vegetation index (EVI) index of MODIS images; November-March). The variables where white-tailed eagles showed greatest shift from overall habitat characteristics in the research area were broadleaved forest (second axis from the principal component analysis of the EVI index), height above the sea level, distance from the small settlements, vertical distance to channel network - all with negative loadings. The results clearly reveal the disproportion of suitable forests for raptors that were cut down in comparison to maturation of suitable forests. PMID:21800060
Radovi?, Andreja; Jelaska, Sven D
In 2003, a survey at waste management grounds and tire dealerships was conducted to determine the species composition of mosquitoes in tires in southern Manitoba, Canada. Over 25% of the 1,142 tires sampled contained a total of 32,474 mosquito larvae and pupae. Culex restuans made up at least 95% of the larvae collected for each month of the summer. Culiseta inornata and Culex tarsalis reached their greatest numbers in July and August, respectively, though they were never abundant. Ochlerotatus triseriatus was also found but never reached more than 1% of the total larvae collected in any given month. Mosquito prevalence was more than three times greater in August (36.1%) than in June (11.7%). Orientation affected prevalence of mosquitoes in tires: 31.4% of vertical tires (tires standing on their treads) contained mosquitoes, whereas mosquitoes were found in only 18.9% of horizontal tires (tires parallel to the ground). Tires in the eastern region of Manitoba contained mosquitoes more often (61.7%), irrespective of date, than Winnipeg (25.9%), the central region (29.1%), or the western region (19.8%). Mosquito prevalence was similar across three size categories of tires, car tires (18.8%), truck tires (19.8%), and semi-trailer tires (26.7%), though tractor tires (47.8%) contained significantly more mosquitoes than tires in the other categories. PMID:18697324
McMahon, T J Scott; Galloway, Terry D; Anderson, Robert A
Objective To determine the effects of environmental characteristics of larval habitats on distribution and abundance of anopheline mosquitoes in Bashagard county, a malarious area in southeast of Iran. Methods Larvae were collected monthly using the standard dipping method and identified using a morphological-based key. Environmental characteristics of the larval habitats were recorded. Water samples were taken from habitats during larval collection for physico-chemical characterization. Statistical analyses were performed. Results In total 5?150 anopheline larvae from 36 larval habitats were collected and identified. They comprised of six species: Anopheles culicifacies (29.36%), Anopheles moghulensis (25.20%), Anopheles dthali (18.02%), Anopheles superpictus (17.24%), Anopheles turkhudi (5.17%) and Anopheles stephensi (5.01%). The most common larval habitats were natural and clear water bodies such as riverbeds with sandy substrates and still water. Furthermore, the anopheline larvae were abundant in permanent and full sunlight habitats without vegetation and algae. Larval density was positively correlated with water temperature. Chemical characteristics including conductivity, total alkalinity, sulphate and chloride had significant effects on distribution and abundance of anopheline species. Conclusions The result of this study indicates a correlation between some environmental characteristics and anopheline larvae abundance which can be considered for effective planning and implementing malaria elimination program in Iran.
Soleimani-Ahmadi, Moussa; Vatandoost, Hassan; Zare, Mehdi
Full Text Available SciELO Brazil | Language: English Abstract in english Used vehicle tires are a source of mosquito vectors and a means of their introduction and expansion. With the aim of assessing the effects of urbanisation on the main mosquito vectors in temperate Argentina, the infestation levels of Aedes aegypti (L.) and Culex pipiens L. were studied in used tires [...] from highly urbanised cities to low-urbanised small towns in Buenos Aires. Immatures of both species accounted for 96% of the 9,722 individuals collected; the total individuals collected represented seven species. The percentage of water-filled tires containing mosquitoes [container index (CI)] was 33% and the percentage of infested sites [site index (SI)] was 65.2%. These indexes decreased significantly from low to high urbanisation levels for both mosquito species. The relative abundance (RA) of Ae. aegypti immatures was slightly higher toward large cities, but showed no difference for Cx. pipiens. The CI of shaded tires was significantly higher than the CI of exposed tires for both mosquito species. There was no difference in RA values between shaded and sunlit tires. The CI and the SI were highest during the summer across the urbanisation levels, except for Cx. pipiens, which continued to increase during the autumn in small towns. Results related to urbanisation gradient, sunlit exposure and seasonality are discussed.
Rubio, Alejandra; Cardo, María Victoria; Vezzani, Darío.
A trail census was conducted of the breeding birds found in three major habitats in the Field Irradiator Gamma area at the Whiteshell Nuclear Research Establishment, Pinawa, Manitoba. The area sampled was about 10.50 ha in size, and included 4.25 ha of upland forest, 4.75 ha of lowland conifers, and 1.50 ha of black spruce-tamarack bog. Forty-four species of birds were identified, of which 24 were considered to be resident in the study area. The highest population density was observed in the bog, followed by upland forest and lowland conifer respectively. In contrast, species diversity was greatest in the upland forest, while it decreased markedly in the relatively monotypic lowland conifer and bog habitats. (author)
This study elucidated the relationships between larval habitat soil-substrate Organic Matter Content (OMC) and immature development of the mosquito Anopheles gambiae S.L. Day-old larvae of the mosquito were reared in media substrated with typical soil samples (i.e., sandy, silt, clayey and loamy soils), from established anopheline breeding sites, to provide a gradient in soil-substrate OMC. The OMC of the soil samples were determined by ignition to a constant weight; while the developing A. gambiae mosquitoes in the culture media were monitored daily for survivorship and duration of immature life stages. The results indicated significant (p 0.05) among the soil-substrate types; results contrary to those of Larval Success Rates (LSR) (i.e., range = 52.07 +/- 13.64 to 74.39 +/- 6.60%). Daily Pupation Rate (DPR) of the mosquitoes varied significantly among the soil-substrates, ranging from 13.87 +/- 2.39% in clayey to 25.00 +/- 4.30% in loamy substrates. Soil-substrate OMC significantly extended the Duration of Immature Life Stages (DILS) of the mosquitoes only in the sandy soil type (range = 12.76 +/- 1.74 to 15.81 +/- 2.40 days). On the whole, DILS was inversely related to soil-substrate OMC. Cross-correlational analysis revealed significant positive association among most of the variables tested. The findings of this study should serve as baseline information for the development of effective environmental management strategies for malaria larval-vector control. PMID:24171275
Olayemi, I K; Ojo, V O
Full Text Available This study elucidated the relationships between larval habitat soil-substrate Organic Matter Content (OMC and immature development of the mosquito Anopheles gambiae s.l. Day-old larvae of the mosquito were reared in media substrated with typical soil samples (i.e., sandy, silt, clayey and loamy soils, from established anopheline breeding sites, to provide a gradient in soil-substrate OMC. The OMC of the soil samples were determined by ignition to a constant weight; while the developing A. gambiae mosquitoes in the culture media were monitored daily for survivorship and duration of immature life stages. The results indicated significant (p0.05 among the soil-substrate types; results contrary to those of Larval Success Rates (LSR (i.e., range = 52.07±13.64 to 74.39±6.60%. Daily Pupation Rate (DPR of the mosquitoes varied significantly among the soil-substrates, ranging from 13.87±2.39% in clayey to 25.00±4.30% in loamy substrates. Soil-substrate OMC significantly extended the Duration of Immature Life Stages (DILS of the mosquitoes only in the sandy soil type (range = 12.76±1.74 to 15.81±2.40 days. On the whole, DILS was inversely related to soil-substrate OMC. Cross-correlational analysis revealed significant positive association among most of the variables tested. The findings of this study should serve as baseline information for the development of effective environmental management strategies for malaria larval-vector control.
Full Text Available SciELO Brazil | Language: English Abstract in english To classify mosquito species based on common features of their habitats, samples were obtained fortnightly between June 2001-October 2003 in the subtropical province of Chaco, Argentina. Data on the type of larval habitat, nature of the habitat (artificial or natural), size, depth, location related [...] to sunlight, distance to the neighbouring houses, type of substrate, organic material, vegetation and algae type and their presence were collected. Data on the permanence, temperature, pH, turbidity, colour, odour and movement of the larval habitat's water were also collected. From the cluster analysis, three groups of species associated by their degree of habitat similarity were obtained and are listed below. Group 1 consisted of Aedes aegypti. Group 2 consisted of Culex imitator, Culex davisi, Wyeomyia muehlensi and Toxorhynchites haemorrhoidalis separatus. Within group 3, two subgroups are distinguished: A (Psorophora ferox, Psorophora cyanescens, Psorophora varinervis, Psorophora confinnis, Psorophora cingulata, Ochlerotatus hastatus-oligopistus, Ochlerotatus serratus, Ochlerotatus scapularis, Culex intrincatus, Culex quinquefasciatus, Culex pilosus, Ochlerotatus albifasciatus, Culex bidens) and B (Culex maxi, Culex eduardoi, Culex chidesteri, Uranotaenia lowii, Uranotaenia pulcherrima, Anopheles neomaculipalpus, Anopheles triannulatus, Anopheles albitarsis, Uranotaenia apicalis, Mansonia humeralis and Aedeomyia squamipennis). Principal component analysis indicates that the size of the larval habitats and the presence of aquatic vegetation are the main characteristics that explain the variation among different species. In contrast, water permanence is second in importance. Water temperature, pH and the type of larval habitat are less important in explaining the clustering of species.
Stein, Marina; Ludueña-Almeida, Francisco; Willener, Juana Alicia; Almirón, Walter Ricardo.
Full Text Available Remotely sensed multi-spectral and -spatial data facilitates the study of mosquito-borne disease vectors and their response to land use and cover composition in the urban environment. In this study we assess the feasibility of integrating remotely sensed multispectral reflectance data and LiDAR (Light Detection and Ranging-derived height information to improve land use and land cover classification. Classification and Regression Tree (CART analyses were used to compare and contrast the enhancements and accuracy of the multi-sensor urban land cover classifications. Eight urban land-cover classes were developed for the city of Tucson, Arizona, USA. These land cover classes focus on pervious and impervious surfaces and microclimate landscape attributes that impact mosquito habitat such as water ponds, residential structures, irrigated lawns, shrubs and trees, shade, and humidity. Results show that synergistic use of LiDAR, multispectral and the Normalized Difference Vegetation Index data produced the most accurate urban land cover classification with a Kappa value of 0.88. Fusion of multi-sensor data leads to a better land cover product that is suitable for a variety of urban applications such as exploring the relationship between neighborhood composition and adult mosquito abundance data to inform public health issues.
Willem J. D. van Leeuwen
Here, I present the first comparison of the abundance of farmland birds in energy grass fields and in cereal-dominated conventionally cultivated fields (CCFs). I demonstrate that in boreal farmland, skylark (Alauda arvensis) densities were significantly lower in reed canary grass (RCG) (Phalaris arundinacea) fields than in CCFs. I found that during the early breeding season RCG fields and CCFs are equally good habitats, but over the ensuing couple of weeks RCG rapidly grows too tall and dense for field-nesting species. Consequently, RCG is an inferior habitat for skylark for laying replacement clutches (after failure of first nesting) or for a second clutch after one successful nesting. The results imply that if RCG cultivation is to be expanded, the establishment of large monocultures should be avoided in farmland landscapes; otherwise the novel habitat may affect detrimentally the seriously depleted skylark population, and probably also other field-nesting bird species with similar breeding habitats. (author)
Vepsaelaeinen, Ville [Finnish Museum of Natural History, P.O. Box 17, University of Helsinki, FI-00014 Helsinki (Finland)
The present work evaluates the use of species distribution model (SDM) algorithms to classify high density of small container Aedes mosquitoes at a fine scale, in the Bermuda islands. Weekly ovitrap data collected by the Health Department of Bermuda (UK) for the years 2006 and 2007 were used for the models. The models evaluated included the following algorithms: Bioclim, Domain, GARP, logistic regression, and MaxEnt. Models were evaluated according to performance and robustness. The area Rece...
We exploited elevation gradients (1,500-2,400 m) ranging from plains to montane areas along the Poudre River and Big Thompson River in the northern Colorado Front Range to determine how mosquito species richness, composition, and abundance change along natural habitat-climate-elevation gradients. Mosquito collections in 26 sites in 2006 by using CO2-baited CDC light traps yielded a total of 7,136 identifiable mosquitoes of 27 species. Commonly collected species included Aedes vexans (Meigen) (n = 4,722), Culex tarsalis Coquillett (n = 825), Ochlerotatus increpitus (Dyar) (n = 546), Ochlerotatus trivittatus (Coquillett) (n = 303), Aedes cinereus Meigen (n = 280), Ochlerotatus melanimon (Dyar) (n = 146), Ochlerotatus dorsalis (Meigen) (n = 67), Culiseta inornata (Williston) (n = 52), Ochlerotatus pullatus (Coquillett) (n = 38), Ochlerotatus spencerii idahoensis (Theobald) (n = 37), and Culex pipiens L. (n = 29). Species richness was highest in plains habitats at elevations below 1,600 m. Numerous species were found exclusively or predominantly at low elevations below 1,700 m [Anopheles earlei Vargas, Anophelesfreeborni Aitken, Coquilletidia perturbans (Walker), Culex erythrothorax (Dyar), Cx. pipiens, Culex territans Walker, Oc. dorsalis, Ochlerotatus hendersoni (Cockerell), Oc. melanimon, and Oc. trivittatus], whereas others occurred predominantly at high elevations above 2,300 m [Ae. cinereus, Culiseta incidens (Thomson), Culiseta morsitans (Theoblad), Ochlerotatus cataphylla (Dyar), Ochlerotatus intrudens (Dyar), Oc. pullatus, and Ochlerotatus punctor (Kirby)]. Ae. vexans and Cx. tarsalis were abundant in the plains ( 19.5 degrees C), occurred at low abundances in foothills and low montane areas (1,610-1,730 m; 18.0-19.5 degrees C), and they were collected only sporadically in montane areas above 1,750 m (mean June-August temperature < 17.5 degrees C). These findings suggest that future climate warming may lead to shifts in distribution patterns of West Nile virus vectors (e.g., Cx. tarsalis) toward higher elevations in Colorado. PMID:18714885
Eisen, Lars; Bolling, Bethany G; Blair, Carol D; Beaty, Barry J; Moore, Chester G
Laboratory studies were carried out to investigate the role of larval habitat-derived microorganisms in the production of semiochemicals for oviposition site selection by Anopheles gambiae Giles sensu stricto mosquitoes. Dual-choice bioassays with gravid females were conducted in standard mosquito cages. Field-collected or laboratory-reared mosquitoes, individually or in groups, were offered a choice between unmodified (water or soil from a natural breeding site) or modified substrates (filte...
Sumba, L. A.; Guda, T. O.; Deng, A. L.; Hassanali, A.; Beier, J. C.; Knols, B. G. J.
Objective To determine ecology and characteristics of the larval habitats of the genus Anopheles (Dipetra: Culicidae) in Aligudarz County, western Iran. Methods This descriptive cross-sectional research was carried out to study the anopheline larvae ecology in seven rural districts, Aligudarz County, from late April to late November 1997. Larvae were captured using the dipping method. Larval breeding places characteristics were noted according to water situation (turbid or clean, stagnant or running), substrate type, site type (man-made or natural), sunlight situation, site situation (transient or permanent, with or without vegetation). Results A total of 9?620 3rd and 4th instar larvae of Anopheles from 115 breeding places in 22 villages were captured, which belonged to the following species: Anopheles stephensi, Anopheles d'thali, Anopheles apoci, Anopheles superpictus (forms A and B), Anopheles marterii sogdianus, Anopheles turkhodi, Anopheles maculipennis S.L and Anopheles claviger. Anopheles stephensi, Anopheles maculipennis S.L and Anopheles apoci were collected for the first time in this county. Anopheles superpictus (93.18%) was the most prevailed one and dispersed over the entire region. Larval habitats consisted of nine natural and three artificial larval habitats. The most important larval habitats were river edges (54.8%), rice fields (12.2%), and grassland (8.7%) with permanent or transient, stagnant or running and clean water, with or without vegetation, sand or mud substrate in full sunlight area. Conclusions Regarding this research, river edges and rice fields are the most important breeding places of malaria vectors in Aligudarz County. It is worthy of note in larvicidal programs.
Amani, Hamid; Yaghoobi-Ershadi, Mohammad Reza; Kassiri, Hamid
Abstract Background This study characterized Anopheles mosquito larval habitats in relation to ecological attributes about the habitat and community-level drainage potential, and investigated whether agricultural activities within or around urban households increased the probability of water body occurrence. Malindi, a city on the coast of Kenya, was mapped using global positioning system (GPS) technology, and a geographic information system (GIS) was used to overlay...
Studies on seasonal prevalence and succession of mosquitoes in rice fields, revealed the dominance of Anopheles culicifacies and An. subpictus in newly transplanted fields during early months of rice cultivation, which was later replaced by the species like An. annularis, An. barbirostris, An. nigerrimus and An. tessellatus with the growth in plant height. Among culicines, except Cx. quinquefasciatus other species were prevalent during growing and later stages of the rice crop. Larval density was found inversely proportional to the height of plants, whereas species diversity maximized during growing phase due to equitable number of specimen among species. PMID:1344947
Kant, R; Pandey, S D; Sharma, R C
Studies on ecological succession of anophelines and the malaria vectors were carried out in rice fields located in two ecologically different terrains, i.e. plains and forested hills in Jabalpur district during monsoon (July-October 1995). Nine and fifteen species of anophelines were found breeding in the rice fields of plain and forested hill villages respectively. Anopheles culicifacies and An. subpictus were dominant species in both the areas. The percentage emergence of adults of An. annularis, An. nigerrimus and An. pallidus was higher in plain villages while the percentage of An. theobaldi, An. fluviatilis and An. jeyporiensis was higher in forested hill villages. Among malaria vectors, three species were found breeding in rice fields of hilly terrain, i.e. An. culicifacies, An. fluviatilis and An. stephensi whereas in rice fields of plains An. culicifacies and An. fluviatilis were recorded. PMID:9699423
Mishra, A K; Singh, N
We used occupancy and productivity data collected at 67 cliffs used for nesting from 1972 to 1999 to assess patterns of distribution and nest-site selection in an increasing population of Peregrine Falcons (Falco peregrinus) in central West Greenland. Peregrine Falcons breeding at traditionally occupied cliffs used for nesting had significantly lower variation in productivity and thus these cliffs were better quality sites. This indicates that Peregrine Falcons occupied cliffs according to a pattern of despotic distribution. Falcons breeding at cliffs that were consistently occupied during the breeding season had higher average productivity and lower variation in productivity than falcons at inconsistently occupied cliffs, and thus consistent occupancy also was indicative of cliff quality. Features of high quality habitat included tall cliffs, greater change in elevation from the lowest point within 3 km of the cliff to the cliff top (elevation gain), and protection from weather on the eyrie ledge. Spacing of suitable and occupied cliffs also was an important feature, and the best cliffs generally were more isolated. Increased spacing was likely a mechanism for reducing intraspecific competition. Our results suggest that Peregrine Falcons use a resource defense strategy to compete for better quality habitats and may use spacing and physical features of a nest site to identify good quality breeding habitat. ?? The Cooper Ornithological Society 2006.
Wightman, C. S.; Fuller, M. R.
Dispersal is a critical life history behavior for mosquitoes and is important for the spread of mosquito-borne disease. We implemented the first stable isotope mark-capture study to measure mosquito dispersal, focusing on Culex pipiens in southwest suburban Chicago, Illinois, a hotspot of West Nile virus (WNV) transmission. We enriched nine catch basins in 2010 and 2011 with 15N-potassium nitrate and detected dispersal of enriched adult females emerging from these catch basins using CDC light and gravid traps to distances as far as 3 km. We detected 12 isotopically enriched pools of mosquitoes out of 2,442 tested during the two years and calculated a mean dispersal distance of 1.15 km and maximum flight range of 2.48 km. According to a logistic distribution function, 90% of the female Culex mosquitoes stayed within 3 km of their larval habitat, which corresponds with the distance-limited genetic variation of WNV observed in this study region. This study provides new insights on the dispersal of the most important vector of WNV in the eastern United States and demonstrates the utility of stable isotope enrichment for studying the biology of mosquitoes in other disease systems.
Hamer, Gabriel L.; Anderson, Tavis K.; Donovan, Danielle J.; Brawn, Jeffrey D.; Krebs, Bethany L.; Gardner, Allison M.; Ruiz, Marilyn O.; Brown, William M.; Kitron, Uriel D.; Newman, Christina M.; Goldberg, Tony L.; Walker, Edward D.
Phlebotomine sand flies transmit Leishmania, phlebo-viruses and Bartonella to humans. A prominent gap in our knowledge of sand fly biology remains the ecology of their immature stages. Sand flies, unlike mosquitoes do not breed in water and only small numbers of larvae have been recovered from diverse habitats that provide stable temperatures, high humidity and decaying organic matter. We describe studies designed to identify and characterize sand fly breeding habitats in a Judean Desert focu...
Moncaz, Aviad; Faiman, Roy; Kirstein, Oscar; Warburg, Alon
Full Text Available Background & objectives: The ecology and distribution of various mosquito species is important inthe determination of mosquito vector abundance and associated diseases prevalence. The distributionof various mosquito genera in natural and artificial habitats and their relative species abundancewas studied between August 2002 and July 2003 in three foci (Uromi, Ekpoma and Auchi comprisingthe Esan and Etsako regions of Midwestern Nigeria.Methods: Sampling was carried out by the method of Hopkins (1952 by dipping using a pipette orladle depending on container types. Pooled contents of smaller containers were sampled with a pondnet. All breeding sources of mosquito larvae were grouped into five (5 depending on their nature,constitution and the physiochemical properties. Artificial mosquito cultures were also carried out infour different container types; plastics, metal cans, earthenware pots and bamboo strips, in parts oftwo different macro habitats subdivided into area of high human activities (AHHA and areas ofderived/secondary vegetation (ADSV. Environmental temperatures, rainfall and relative humiditywere monitored during the study.Results: The present study revealed 17 mosquito species belonging to three genera (Anopheles,Culex and Aedes which are potential vectors of four human diseases in the areas surveyed. A total of736 mosquito larvae were encountered in artificial sources and 568 larvae were harvested from naturalsources. Pools, plastics and metal cans were the predominant artificial sources of mosquito larvae.Conclusion: The contribution of human activities and increasing environmental modification to thebreeding of human disease vector mosquitoes is of importance and selective vector control measuresincluding larviciding are recommended particularly before onset of rainy season
Godwin R.A. Okogun, Jude C. Anosike, Anthony N. Okere & Bethran E.B. Nwoke
Migrating humpback whales from northern and southern feeding grounds come to the tropical waters near Osa Peninsula, Pacific of Costa Rica, to reproduce and raise their calves. Planning effective marine protected areas that encompass humpback critical habitats require data about which oceanographic features influence distribution during the breeding period. This study examines the relationship between water depth and ocean floor slope with humpback whale distribution, based on sightings durin...
Oviedo, L.; Soli?s, M.
We modeled surface wetness at high resolution, using a dynamic hydrology model, to predict flood and swamp water mosquito abundances. Historical meteorologic data, as well as topographic, soil, and vegetation data, were used to model surface wetness and identify potential fresh and swamp water breeding habitats in two northern New Jersey watersheds. Surface wetness was positively associated with the subsequent abundance of the dominant floodwater mosquito species, Aedes vexans, and the swamp ...
Shaman, Jeffrey; Stieglitz, Marc; Stark, Colin; Le Blancq, Sylvie; Cane, Mark
This report, conducted from May through July 2000, addressed the potential effect of compressor noise on breeding birds in gas-production areas administered by the FFO, specifically in the Rattlesnake Canyon Habitat Management Area northeast of Farmington, New Mexico. The study was designed to quantify and characterize noise output from these compressors and to determine if compressor noise affected bird populations in adjacent habitat during the breeding season.
LaGory, K.E.; Chang, Young-Soo; Chun, K.C.; Reeves, T.; Liebich, R.; Smith, K.
We used empirical and modeling approaches to examine effects of plant breeding systems on demographic responses to habitat fragmentation. Empirically, we investigated effects of local flowering plant density on pollination and of population size on mate availability in a common, self-incompatible purple coneflower, Echinacea angustifolia, growing in fragmented prairie habitat. Pollination and recruitment increased with weighted local density around individual flowering plants. This positive density dependence is an Allee effect. In addition, mean mate compatibility between pairs of plants increased with population size. Based on this empirical study, we developed an individual-based, spatially explicit demographic model that incorporates autosomal loci and an S locus. We simulated habitat fragmentation in populations identical except for their breeding system, self-incompatible (SI) or self-compatible (SC). Both populations suffered reduced reproduction in small patches because of scarcity of plants within pollination distance (potential mates) and inbreeding depression. But SI species experienced an additional, genetic contribution to the Allee effect (S-Allee effect) caused by allele loss at the S locus, which reduces mate availability, thereby decreasing reproduction. The strength of the S-Allee effect increases through time (i.e., patches age) because random genetic drift reduces S-allele richness. We investigate how patch aging influences extinction and discuss how the S-Allee effect influences communities in fragmented habitat. PMID:17230399
Wagenius, Stuart; Lonsdorf, Eric; Neuhauser, Claudia
Control of aquatic-stage Anopheles is one of the oldest and most historically successful interventions to prevent malaria, but it has seen little application in Africa. Consequently, the ecology of immature afrotropical Anopheles has received insufficient attention. We therefore examined the population dynamics of African anopheline and culicine mosquitoes using operationally practicable techniques to examine the relative importance and availability of different larval habitats in an area of ...
Fillinger, U.; Sonye, G.; Killeen, G. F.; Knols, B. G. J.; Becker, N.
Full Text Available A common assumption about malaria, dengue, and other mosquito-borne infections is that the two main components of the risk of human infection-the rate at which people are bitten (human biting rate and the proportion of mosquitoes that are infectious-are positively correlated. In fact, these two risk factors are generated by different processes and may be negatively correlated across space and time in heterogeneous environments. Uneven distribution of blood-meal hosts and larval habitat creates a spatial mosaic of demograPhic sources and sinks. Moreover, mosquito populations fluctuate temporally, forced by environmental variables such as rainfall, temperature, and humidity. These sources of spatial and temporal heterogeneity in the distribution of mosquito populations generate variability in the human biting rate, in the proportion of mosquitoes that are infectious, and in the risk of human infection. To understand how heterogeneity affects the epidemiology of mosquito-borne infections, we developed a set of simple models that incorporate heterogeneity in a stepwise fashion. These models predict that the human biting rate is highest shortly after the mosquito densities peak, near breeding sites where adult mosquitoes emerge, and around the edges of areas where humans are aggregated. In contrast, the proportion of mosquitoes that are infectious reflects the age structure of mosquito populations; it peaks where old mosquitoes are found, far from mosquito breeding habitat, and when mosquito population density is declining. Finally, we show that estimates for the average risk of infection that are based on the average entomological inoculation rate are strongly biased in heterogeneous environments.
Smith David L
Full Text Available SciELO Cuba | Language: Spanish Abstract in spanish Introducción: la identificación de las especies de mosquitos en cada municipio en Cuba forma parte del Programa de Control de Aedes aegypti y Aedes albopictus, lo cual representa un factor importante en la aparición de eventos epidemiológicos o zoonóticos que involucren estos insectos. Objetivo: con [...] ocer la riqueza de especies de mosquitos y su distribución en el municipio Boyeros. Métodos: el trabajo se desarrolló en el municipio Boyeros, La Habana en el período 1982-2011. Las muestras de mosquitos se colectaron por los trabajadores del programa de control de Aedes aegypti y Aedes albopictus. Resultados: la riqueza de especies de mosquitos fue de 35, de estas 10 se encuentran distribuidas en todas las áreas del municipio. El área con mayor riqueza de especie fue Mulgoba seguida por Wajay, y la de menor correspondió a Boyeros. Se colectaron 8 especies en depósitos artificiales y naturales como hueco de árboles; mientras que 22 se colectaron en reservorios de aguas naturales, lagunas de oxidación, zanjas, arroyos, lagunatos y ríos. Del total de especies, 5 solo fueron colectadas en estadio adulto. Conclusiones: la emergencia y reemergencia de algunas enfermedades transmitidas por mosquitos es uno de los aspectos que más seguimiento tiene en estos momentos en el continente americano, por lo que conocer la fauna de mosquitos del municipio así como su distribución es importante. De presentarse algún brote o epidemia que involucren a estos insectos obligaría a establecer las estrategias de control, para evitar la propagación de enfermedades de transmisión vectorial. Abstract in english Introduction: the identification of mosquito species in each municipality of Cuba is part of the Aedes aegypti and Aedes albopictus control program. This is an important factor in the occurrence of epidemiological or zoonotic events involving these insects. Objective: to identify the wealth of mosqu [...] ito species and their distribution in Boyeros municipality. Methods: the study was developed in Boyeros municipality from 1982 to 2011. The mosquito samples were taken by the Aedes aegypti and Aedes albopictus control program workers. Results: the wealth of mosquito species includes 35 species of which 10 are distributed in all the areas of the municipality. The area with the largest wealth of species was Mulgoba, followed by Wajay, and the smallest one was found in Boyeros. Eight species were collected in artificial and natural reservoirs such as tree holes, whereas 22 were observed in natural water reservoirs, oxidation lagoons, ditches, streams and rivers. Of all the species, just 5 were collected in their adult stage. Conclusions: emergency and reemergence of some mosquito-borne diseases is one of the more watched aspects at this time in the American continent, thus the mosquito fauna of the municipality and its distribution is fundamental. If any outbreak or epidemic involving these insects occurs, it would be compulsory to set up control strategies to prevent the spread of vector-borne diseases.
Valdés Miró, Vivian; Reyes Arencibia, Mayra; Marquetti Fernández, María del Carmen; González Broche, Raúl.
Full Text Available Abstract Background As the ecology of mosquito larvae can be complex there is need to develop a rational framework for undertaking larval ecological studies. Local environmental characteristics, such as altitude, climate and land use, can significantly impact on phenology and population dynamics of mosquito larvae, and indirectly affect the dynamics of mosquito-borne diseases. The aim of this study was to assess the feasibility of implementing an integrated approach to larval source management under the distinct ecological settings. Methods The study was conducted in two highland villages and one village, at a lower altitude, in the Lake Victoria basin, where malaria is endemic and transmitted by the same Anopheles mosquito species. In each village the stability of mosquito larval habitats was classified as either temporary or permanent. The productivity of these habitat types was quantified by carrying out weekly larval sampling using a standard dipping method for a period of two years. During sampling the physical characteristic of the larval habitat, including the vegetation cover were noted. Ambient temperature, rainfall and relative humidity were recorded on a 21 × Micro-datalogger in each study site. Results Anopheles gambiae sensu lato larvae were found in all study sites. Anopheles arabiensis was more abundant (93% in Nyalenda (Lake Victoria basin and Fort Ternan (highland area; 71%. In Lunyerere (highland area, An. gambiae sensu stricto comprised 93% of the total An. gambiae s.l. larvae. Larvae of An. gambiae s.l. mosquitoes were present in both temporary and permanent habitats with monthly variations dependent on rainfall intensity and location. Anopheles larvae were more likely to be found in man-made as opposed to natural habitats. Grassy habitats were preferred and were, therefore, more productive of Anopheles larvae compared to other habitat types. Weekly rainfall intensity led to an increase or decrease in mosquito larval abundance depending on the location. Conclusion The majority of mosquito breeding habitats were man made in all sites. Both temporary and permanent habitats were suitable for An. gambiae breeding. In Fort Ternan temporary sites were favoured for mosquito breeding above permanent sites. Significant differences in larval abundance were found depending on weekly rainfall intensity. Larval source management programmes should target permanent and temporary habitats equally and work closely with land and home owners as a majority of the breeding habitats are man made.
Mukabana Wolfgang R
Believing that science is about precision in defining its terms, we propose the use of breeding as an all-encompassing term for mosquito activity does not always represent the reality of what is happening at a site where mosquitoes, in whatever stage, are present. We explore the breadth of the term breeding and propose alternative, more accurate uses for those who write about mosquitoes. We offer samples of what we see as a misuse of the word and provide what we feel is more scientifically acceptable terminology. PMID:17067065
Rupp, Henry; Bosak, Peter J; Reed, Lisa M
Full Text Available Introduction & Objective: The aim of the study was to identify larval habitats and new species and determine the exact distribution of Culicidae in Hamadan Province.Materials & Methods: This descriptive,cross -sectional study was conducted in six regions of Hamadan Province during 2010. Sampling method was carried out by standard Dipping method. Specimens were mounted by lactophenol solution and were sent to Medical Entomology Laboratory, Tehran University of Medical Sciences with related codes. The accurate diagnosis of Culex pipiens was made with male genitalia morphology. The data were analyzed using standard statistical software (SPSS version 11.5. Results: In total, 4751 larvae of the three genera including Anopheles, Culex, Culiseta ,and nine species including An.superpictus, An.maculipennis sl and An.claviger, Cx.pipiens,Cx.theileri, Cx.hortensis and Cx.prexiguuus ,Cu.longiareolata ,and Cu.subochrea in 36 larval habitat sites in the province were collected and identified. Among Culicidae larvae collected, Culex. Pipiens and Culiseta.subochrea with 58%, and 0.4% of samples were the most and the least species collected. Conclusion: Culex pipiens was reported as the dominant species . Based on morphology of male genitalia, only Culex pipiens was identified among the complex species .The species of Anopheles claviger and Culex prexiguus were found for the first time in this area. The molecular analysis and the egg ridge counts of anopheles maculipennis sl must be extensively studied in the future. (Sci J Hamadan Univ Med Sci 2011;18(3:50-58
In a study covering two years, 1306 samples of immatures were collected from 7 different breeding habitats of canal irrigated villages of Kheda district in Gujarat. Out of the samples belonging to 8 anopheline species, 14396 adults emerged. Breeding of An. culicifacies was associated with An. annularis in ponds, paddy fields, small pools and with An. stephensi in paddy fields. Maximum association was observed between An. barbirostris and An. nigerrimus in irrigation canals and An. culicifacies and An. subpictus in intradomestic containers. An. annularis, An. stephensi and An. subpictus were strongly associated in paddy fields. Strong interspecific repulsion was observed between An. subpictus and An. stephensi in intradomestic containers and An. barbirostris and An. subpictus in ponds. PMID:2292321
Bhatt, R M; Sharma, R C; Kohli, V K
To control container-breeding mosquitoes in the small island of Minnajima (0.56 km2), northern Okinawa, Japan, laboratory-reared adults (aged 7-10 days) of Toxorhynchites splendens (Palawan strain), a mosquito with predatory larvae, were released repeatedly during 1984, 1986 and 1987. Thirteen species of mosquitoes (Diptera: Culicidae) occurred in artificial containers, ground pools or crab-holes on the island, the predominant species being Aedes (Stegomyia) albopictus and Culex (Culex) quinquefasciatus. Predatory mosquito larvae of Culex (Lutzia) fuscanus and Cx (Lt.) halifaxii were found commonly in wet containers. In the first year of study, during a period of 54 days from 13 May to 5 July 1984, totals of 879 female and 806 male adults of Tx.splendens were released on six occasions. Similarly, between 29 April and 30 August 1986, totals of 2920 female and 2878 male adult Tx.splendens were released. In the third study year, totals of 2041 female and 1783 male Tx.splendens were released on eight occasions during 199 days from 23 April to 7 November 1987. After adult releases at two sites, the immature stages of Tx.splendens were found in 164 out of 502 traps in 1984, 421 out of 933 traps in 1986, and 151 out of 502 traps in 1987. The number of immatures of Tx.splendens present in each trap varied from 1 to 40 in 1984, 1 to 29 in 1986 and 1 to 9 in 1987. Numbers of immatures of the target species found in the traps during August-September averaged 71.9/trap/month in 1984, 114.7/trap/month in 1986 and 36.0/trap/month in 1987, significantly less in the traps with Tx.splendens than in those without them. The present field studies indicated that, in this small island, approximately 250 adult female and 200 male Tx.splendens per month should be released from April to November, and the releases should be carried out every year, in order to control effectively the target mosquitoes Ae.albopictus and Cx quinquefasciatus breeding in artificial containers in Minnajima. PMID:1358271
Miyagi, I; Toma, T; Mogi, M
The aquatic insect fauna of salt marshes is poorly characterized, with the possible exception of biting Diptera. Aquatic insects play a vital role in salt marsh ecology, and have great potential importance as biological indicators for assessing marsh health. In addition, they may be impacted by measures to control mosquitoes such as changes to the marsh habitat, altered hydrology, or the application of pesticides. Given these concerns, the goals of this study were to conduct the first taxonomic survey of salt marsh aquatic insects on Long Island, New York, USA and to evaluate their utility for non-target pesticide impacts and environmental biomonitoring. A total of 18 species from 11 families and five orders were collected repeatedly during the five month study period. Diptera was the most diverse order with nine species from four families, followed by Coleoptera with four species from two families, Heteroptera with three species from three families, then Odonata and the hexapod Collembola with one species each. Water boatmen, Trichocorixa verticalis Fieber (Heteroptera: Corixidae) and a shore fly, Ephydra subopaca Loew (Diptera: Ephydridae), were the two most commonly encountered species. An additional six species; Anurida maritima Guérin-Méneville (Collembola: Neanuridae), Mesovelia mulsanti White (Heteroptera: Mesovelidae), Enochrus hamiltoni Horn (Coleoptera: Hydrophilidae), Tropisternus quadristriatus Horn (Coleoptera: Hydrophilidae), Dasyhelea pseudocincta Waugh and Wirth (Diptera: Ceratopogonidae), and Brachydeutera argentata Walker (Diptera: Ephydridae), were found regularly. Together with the less common Erythrodiplax berenice Drury (Odonata: Libellulidae), these nine species were identified as the most suitable candidates for pesticide and environmental impact monitoring due to abundance, position in the food chain, and extended seasonal occurrence. This study represents a first step towards developing an insect-based index of biological integrity for salt marsh health assessment. PMID:22957707
Rochlin, Ilia; Dempsey, Mary E; Iwanejko, Tom; Ninivaggi, Dominick V
Thirty four species of mosquitoes (Diptera: Culicidae) were collected across three phytogeographic zones; tropical (300 to 1000 m), sub tropical (1000 to 2000 m) and temperate (2000 to 3000 m) in the Garhwal region of India. They included 5 genera: Aedes, Anopheles, Armigeres, Culex and Uranotaenia. Of these, the immature forms of 23 species were recovered from different breeding habitats. The larval habitats were seepage pools, river beds, rice fields, tanks, forest pools, ditches, streams, ...
Pemola Devi, N.; Jauhari, R. K.
Water temperature is an important determinant in many aquatic biological processes, including the growth and development of malaria mosquito ( Anopheles arabiensis and A. gambiae) immatures. Water turbidity affects water temperature, as suspended particles in a water column absorb and scatter sunlight and hence determine the extinction of solar radiation. To get a better understanding of the relationship between water turbidity and water temperature, a series of semi-natural larval habitats (diameter 0.32 m, water depth 0.16 m) with increasing water turbidity was created. Here we show that at midday (1300 hours) the upper water layer (thickness of 10 mm) of the water pool with the highest turbidity was on average 2.8°C warmer than the same layer of the clearest water pool. Suspended soil particles increase the water temperature and furthermore change the temperature dynamics of small water collections during daytime, exposing malaria mosquito larvae, which live in the top water layer, longer to higher temperatures.
Paaijmans, K. P.; Takken, W.; Githeko, A. K.; Jacobs, A. F. G.
Full Text Available Migrating humpback whales from northern and southern feeding grounds come to the tropical waters near Osa Peninsula, Pacific of Costa Rica, to reproduce and raise their calves. Planning effective marine protected areas that encompass humpback critical habitats require data about which oceanographic features influence distribution during the breeding period. This study examines the relationship between water depth and ocean floor slope with humpback whale distribution, based on sightings during two breeding seasons (2005 and 2006. Data are from the Southern and Northern subpopulations in the Eastern Tropical Pacific (ETP. Analysis followed the basic principles of the Ecological Niche Factors Analysis (ENFA, where indices of Marginality and Tolerance provide insights on the restrictiveness of habitat use. At a fine scale, physical factors such as water depth and slope define the critical breeding and nursing habitat for M. novaeangliae. Divergence in the subsamples means of depths and slope distribution, with the global mean of the study area in both eco-geographical variables, determine habitat requirements restricted by topographic features such as depths (Las ballenas jorobadas viajan a aguas tropicales para reproducirse y criar a sus ballenatos. Es importante entender las características oceanográficas que influencian su distribución para lograr una planificación efectiva de áreas marinas protegidas con hábitats críticos para estos cetáceos. Este estudio examina la relación entre la profundidad, la pendiente del suelo oceánico y la distribución de estas ballenas, usando avistamientos del 2005 y 2006 en la costa Pacífica de la Península de Osa, Costa Rica (temporada de reproducción del sur y norte en el Pacífico Tropical Oriental. Usamos Análisis de Factores de Nicho Ecológico (ENFA por sus siglas en inglés, donde los índices de Marginalidad y Tolerancia ilustran las restricciones en uso de hábitat. En una escala local, factores físicos como la profundidad y la pendiente definen el hábitat crítico de reproducción y cría de M. novaeangliae. Las divergencias entre las medias de las sub-muestras y la media global del área de estudio en ambas variables eco-geográficas, determinan las limitaciones en requerimientos de hábitat en aspectos topográficos como la profundidad (>100 m y la pendiente del fondo (>10%, localizando los hábitat críticos para reproducción y cría dentro de la plataforma continental. Los planes y propuestas para un sistema de áreas marinas protegidas deben de considerar la conectividad de la isla del Caño y la Bahía de Drake, así como la extensión de los límites marinos del Parque Nacional Corcovado.
Full Text Available SciELO Costa Rica | Language: English Abstract in spanish Las ballenas jorobadas viajan a aguas tropicales para reproducirse y criar a sus ballenatos. Es importante entender las características oceanográficas que influencian su distribución para lograr una planificación efectiva de áreas marinas protegidas con hábitats críticos para estos cetáceos. Este es [...] tudio examina la relación entre la profundidad, la pendiente del suelo oceánico y la distribución de estas ballenas, usando avistamientos del 2005 y 2006 en la costa Pacífica de la Península de Osa, Costa Rica (temporada de reproducción del sur y norte en el Pacífico Tropical Oriental). Usamos Análisis de Factores de Nicho Ecológico (ENFA por sus siglas en inglés), donde los índices de Marginalidad y Tolerancia ilustran las restricciones en uso de hábitat. En una escala local, factores físicos como la profundidad y la pendiente definen el hábitat crítico de reproducción y cría de M. novaeangliae. Las divergencias entre las medias de las sub-muestras y la media global del área de estudio en ambas variables eco-geográficas, determinan las limitaciones en requerimientos de hábitat en aspectos topográficos como la profundidad (>100 m) y la pendiente del fondo (>10%), localizando los hábitat críticos para reproducción y cría dentro de la plataforma continental. Los planes y propuestas para un sistema de áreas marinas protegidas deben de considerar la conectividad de la isla del Caño y la Bahía de Drake, así como la extensión de los límites marinos del Parque Nacional Corcovado. Abstract in english Migrating humpback whales from northern and southern feeding grounds come to the tropical waters near Osa Peninsula, Pacific of Costa Rica, to reproduce and raise their calves. Planning effective marine protected areas that encompass humpback critical habitats require data about which oceanographic [...] features influence distribution during the breeding period. This study examines the relationship between water depth and ocean floor slope with humpback whale distribution, based on sightings during two breeding seasons (2005 and 2006). Data are from the Southern and Northern subpopulations in the Eastern Tropical Pacific (ETP). Analysis followed the basic principles of the Ecological Niche Factors Analysis (ENFA), where indices of Marginality and Tolerance provide insights on the restrictiveness of habitat use. At a fine scale, physical factors such as water depth and slope define the critical breeding and nursing habitat for M. novaeangliae. Divergence in the subsamples means of depths and slope distribution, with the global mean of the study area in both eco-geographical variables, determine habitat requirements restricted by topographic features such as depths (
L, Oviedo; M, Solís.
Characterization of mosquito breeding habitats is often accomplished with the goal of guiding larval control interventions as well as the goal of identifying areas with higher disease risk. This characterization often relies on statistical measures of association (e.g., regression coefficients) between covariates and presence/absence or abundance of larva. Here we contend that these measures of association are not enough; researchers should also study the spatial and temporal distribution of ...
Valle, Denis; Zaitchik, Benjamin; Feingold, Beth; Spangler, Keith; Pan, William
We investigated home-range characteristics and habitat selection by Black-backed Woodpeckers (Picoides arcticus) in an unburned, boreal forest landscape managed by mosaic harvesting in Quebec, Canada. Habitat selection by this species was specifically examined to determine home-range establishment and foraging activities. We hypothesized that Black-backed Woodpeckers would respond to harvesting by adjusting their home-range size as a function of the amount of dead wood available. Twenty-two b...
The Au'au Channel between the islands of Maui and Lanai, Hawaii comprises critical breeding habitat for humpback whales (Megaptera novaeangliae) of the Central North Pacific stock. However, like many regions where marine mega-fauna gather, these waters are also the focus of a flourishing local eco-tourism and whale watching industry. Our aim was to establish current trends in habitat preference in female-calf humpback whale pairs within this region, focusing specifically on the busy, eastern ...
Cartwright, Rachel; Gillespie, Blake; Labonte, Kristen; Mangold, Terence; Venema, Amy; Eden, Kevin; Sullivan, Matthew
Much of the biodiversity associated with isolated wetlands requires aquatic and terrestrial habitat to maintain viable populations. Current federal wetland regulations in the United States do not protect isolated wetlands or extend protection to surrounding terrestrial habitat. Consequently, some land managers, city planners, and policy makers at the state and local levels are making an effort to protect these wetland and neighboring upland habitats. Balancing human land-use and habitat conservation is challenging, and well-informed land-use policy is hindered by a lack of knowledge of the specific risks of varying amounts of habitat loss. Using projections of wood frog (Rana sylvatica) and spotted salamander (Ambystoma maculatum) populations, we related the amount of high-quality terrestrial habitat surrounding isolated wetlands to the decline and risk of extinction of local amphibian populations. These simulations showed that current state-level wetland regulations protecting 30 m or less of surrounding terrestrial habitat are inadequate to support viable populations of pool-breeding amphibians. We also found that species with different life-history strategies responded differently to the loss and degradation of terrestrial habitat. The wood frog, with a short life span and high fecundity, was most sensitive to habitat loss and isolation, whereas the longer-lived spotted salamander with lower fecundity was most sensitive to habitat degradation that lowered adult survival rates. Our model results demonstrate that a high probability of local amphibian population persistence requires sufficient terrestrial habitat, the maintenance of habitat quality, and connectivity among local populations. Our results emphasize the essential role of adequate terrestrial habitat to the maintenance of wetland biodiversity and ecosystem function and offer a means of quantifying the risks associated with terrestrial habitat loss and degradation. PMID:18717698
Harper, Elizabeth B; Rittenhouse, Tracy A G; Semlitsch, Raymond D
Full Text Available Entomological studies to determine the effect of the physical characteristics of mosquito larval breeding water bodies and reservoir water level changes on the occurrence of Anopheles mosquito larvae were conducted in two villages at Koka reservoir in central Ethiopia between August and December 2007. Of the two study villages, Ejersa is located close to the reservoir, and Kuma is 5 km away from it. Data on the type, number and physical characteristics of Anopheles larval breeding habitat, species composition and densities of anopheles mosquitoes in and around the study villages were investigated and recorded. Meteorological and reservoir water level data were compared with availability of Anopheles larval breeding sites and densities. Entomological data, derived from weekly larval collections, showed that Anopheles pharoensis Theobald, Anopheles gambiae s.l. Giles, Anopheles coustani Laveran and Anopheles squamosus Theobald were breeding in the study area. The mean larval density of An. gambiae s.l. in this study was higher in slightly turbid and shallow aquatic habitat than in turbid and relatively deep aquatic habitat. The density of An. pharoensis in habitat with floating vegetation and with relatively shady conditions was significantly higher than that of less shaded aquatic habitat and greater emergent vegetation. There was also a positive correlation between the occurrence of Anopheles larvae with the water and daily minimum atmospheric temperature. Similarly at Ejersa, over the sampling period, there was a positive correlation between falling reservoir water levels and the number of positive breeding habitats. These results confirm that physical characteristics of the water bodies play an important role in the species composition, total Anopheles larval count, and the density of Anopheles mosquitoes. Suitable breeding habitat in the vicinity of the reservoir village was strongly associated with the reservoir. This is particularly important for An. pharoensis and An. gambiae s.l. which are important vectors of malaria in the area.
Entomological studies to determine the effect of the physical characteristics of mosquito larval breeding water bodies and reservoir water level changes on the occurrence of Anopheles mosquito larvae were conducted in two villages at Koka reservoir in central Ethiopia between August and December 2007. Of the two study villages, Ejersa is located close to the reservoir, and Kuma is 5 km away from it. Data on the type, number and physical characteristics of Anopheles larval breeding habitat, species composition and densities of anopheles mosquitoes in and around the study villages were investigated and recorded. Meteorological and reservoir water level data were compared with availability of Anopheles larval breeding sites and densities. Entomological data, derived from weekly larval collections, showed that Anopheles pharoensis Theobald, Anopheles gambiae s.l. Giles, Anopheles coustani Laveran and Anopheles squamosus Theobald were breeding in the study area. The mean larval density of An. gambiae s.l. in this study was higher in slightly turbid and shallow aquatic habitat than in turbid and relatively deep aquatic habitat. The density of An. pharoensis in habitat with floating vegetation and with relatively shady conditions was significantly higher than that of less shaded aquatic habitat and greater emergent vegetation. There was also a positive correlation between the occurrence of Anopheles larvae with the water and daily minimum atmospheric temperature. Similarly at Ejersa, over the sampling period, there was a positive correlation between falling reservoir water levels and the number of positive breeding habitats. These results confirm that physical characteristics of the water bodies play an important role in the species composition, total Anopheles larval count, and the density of Anopheles mosquitoes. Suitable breeding habitat in the vicinity of the reservoir village was strongly associated with the reservoir. This is particularly important for An. pharoensis and An. gambiae s.l. which are important vectors of malaria in the area.
Teklu, B. M.; Tekie, H.; McCartney, M.; Kibret, S.
In laboratory bioassays we tested the predatory capacity of the copepod Mesocyclops annulatus on Aedes aegypti and Culex pipiens larvae. A single adult female of M. annulatus caused 51.6% and 52.3% mortality of 50 first instar larvae of Ae. aegypti and Cx. pipiens respectively, in a 72 h test period. When alternative food was added to the containers, mortality rates declined to 16% and 10.3% for Ae. aegypti and Cx. pipiens respectively. When 50 first instar larvae of each of the two mosquito ...
Micieli, Mari?a V.; Gerardo Marti; Garci?a, Juan J.
The Anopheles Hyrcanus Group consists of several species that are vectors of malaria and other mosquito-borne diseases in the Oriental and Palearctic Regions. The group has about three-quarters of the species that comprise the Myzorhynchus Series of genus...
C. Li H. Kim J. E. Pecor L. M. Rueda T. A. Klein
The Au'au Channel between the islands of Maui and Lanai, Hawaii comprises critical breeding habitat for humpback whales (Megaptera novaeangliae) of the Central North Pacific stock. However, like many regions where marine mega-fauna gather, these waters are also the focus of a flourishing local eco-tourism and whale watching industry. Our aim was to establish current trends in habitat preference in female-calf humpback whale pairs within this region, focusing specifically on the busy, eastern portions of the channel. We used an equally-spaced zigzag transect survey design, compiled our results in a GIS model to identify spatial trends and calculated Neu's Indices to quantify levels of habitat use. Our study revealed that while mysticete female-calf pairs on breeding grounds typically favor shallow, inshore waters, female-calf pairs in the Au'au Channel avoided shallow waters (<20 m) and regions within 2 km of the shoreline. Preferred regions for female-calf pairs comprised water depths between 40–60 m, regions of rugged bottom topography and regions that lay between 4 and 6 km from a small boat harbor (Lahaina Harbor) that fell within the study area. In contrast to other humpback whale breeding grounds, there was only minimal evidence of typical patterns of stratification or segregation according to group composition. A review of habitat use by maternal females across Hawaiian waters indicates that maternal habitat choice varies between localities within the Hawaiian Islands, suggesting that maternal females alter their use of habitat according to locally varying pressures. This ability to respond to varying environments may be the key that allows wildlife species to persist in regions where human activity and critical habitat overlap.
Cartwright, Rachel; Gillespie, Blake; LaBonte, Kristen; Mangold, Terence; Venema, Amy; Eden, Kevin; Sullivan, Matthew
Full Text Available SciELO Brazil | Language: English Abstract in english Immatures of both Aedes aegypti and Aedes albopictus have been found in water-holding bromeliad axils in Brazil. Removal of these plants or their treatment with insecticides in public and private gardens have been undertaken during dengue outbreaks in Brazil despite uncertainty as to their importanc [...] e as productive habitats for dengue vectors. From March 2005-February 2006, we sampled 120 randomly selected bromeliads belonging to 10 species in a public garden less than 200 m from houses in a dengue-endemic neighborhood in Rio de Janeiro. A total of 2,816 mosquito larvae and pupae was collected, with an average of 5.87 immatures per plant per collection. Culex (Microculex) pleuristriatus and Culex spp of the Ocellatus Group were the most abundant culicid species, found in all species of bromeliads; next in relative abundance were species of the genus Wyeomyia. Only two individuals of Ae. aegypti (0.07%) and five of Ae. albopictus(0.18%) were collected from bromeliads. By contrast, immatures of Ae. aegypti were found in manmade containers in nearly 5% of nearby houses. These results demonstrate that bromeliads are not important producers of Ae. aegypti and Ae. albopictus and, hence, should not be a focus for dengue control. However, the results of this study of only one year in a single area may not represent outcomes in other urban localities where bromeliads, Ae. aegypti and dengue coincide in more disturbed habitats.
Márcio Goulart, Mocellin; Taynãna César, Simões; Teresa Fernandes Silva do, Nascimento; Maria Lucia França, Teixeira; Leon Philip, Lounibos; Ricardo Lourenço de, Oliveira.
An investigation of habitat preference for larval breeding sites by Aedes (Diptera: Culicidae) mosquitoes which occur around human dwellings in Ishigaki-jima and Taketomi-jima Islands revealed that Ae. albopictus Skuse 1894 preferred pools in tires and boats and was distributed widely from the coast, inland. Although Ae. riversi Bohart & Ingram, 1946 and Ae. flavopictus miyarai (Tanaka et al, 1979) shared tree holes as larval breeding sites, Ae. riversi was collected near the ocean whereas Ae. flavopictus miyarai was collected inland. Ae. togoi Theobald, 1907 was collected near the coast and strongly preferred boats. Our study showed that habitat preference was different between four species of Aedes mosquito in Ishigaki-jima and Taketomi-jima Islands. PMID:23413700
Tsunoda, Takashi; Fukuchi, Atsuko; Nanbara, Sho; Higa, Yukiko; Takagi, Masahiro
We conducted studies on mosquitoes and West Nile virus (WNV) along a riparian corridor following the South Platte River and Big Thompson River in northeastern Colorado and extending from an elevation of 1,215 m in the prairie landscape of the eastern Colorado plains to 1,840 m in low montane areas at the eastern edge of the Rocky Mountains in the central part of the state. Mosquito collection during June-September 2007 in 20 sites along this riparian corridor yielded a total of 199,833 identifiable mosquitoes of 17 species. The most commonly collected mosquitoes were, in descending order: Aedes vexans, Culex tarsalis, Ae. dorsalis, Ae. trivittatus, Ae. melanimon, Cx. pipiens, and Culiseta inornata. Species richness was higher in the plains than in foothills-montane areas, and abundances of several individual species, including the WNV vectors Cx. tarsalis and Cx. pipiens and the nuisance-biter and potential secondary WNV vector Ae. vexans, decreased dramatically from the plains (1,215-1,487 m) to foothills-montane areas (1,524-1,840 m). Ae. vexans and Cx. tarsalis had a striking pattern of uniformly high abundances between 1,200-1,450 m followed by a gradual decrease in abundance above 1,450 m to reach very low numbers above 1,550 m. Culex species were commonly infected with WNV in the plains portion of the riparian corridor in 2007, with 14 of 16 sites yielding WNV-infected Cx. tarsalis and infection rates for Cx. tarsalis females exceeding 2.0 per 1,000 individuals in ten of the sites. The Vector Index for abundance of WNV-infected Cx. tarsalis females during June-September exceeded 0.5 in six plains sites along the South Platte River but was uniformly low (0-0.1) in plains, foothills and montane sites above 1,500 m along the Big Thompson River. A population genetic analysis of Cx. tarsalis revealed that all collections from the ?190 km riparian transect in northeastern Colorado were genetically uniform but that these collections were genetically distinct from collections from Delta County on the western slope of the Continental Divide. This suggests that major waterways in the Great Plains serve as important dispersal corridors for Cx. tarsalis but that the Continental Divide is a formidable barrier to this WNV vector. PMID:20836831
Barker, Christopher M; Bolling, Bethany G; Black, William C; Moore, Chester G; Eisen, Lars
Successful management practices of avian populations depend on understanding relationships between birds and their habitat, especially in rare habitats, such as riparian areas of the desert Southwest. Remote-sensing technology has become popular in habita...
C. Ripper T. M. McFarland
Entomological studies to determine the effect of the physical characteristics of larval breeding water bodies and reservoir water level changes on the occurrence of Anopheles mosquito larvae and on the spatial and temporal formation of larval breeding habitats were conducted in two villages at Koka reservoir between August and December 2007. Of the two study villages, Ejersa is in close proximity to the reservoir, and Kuma is 5 km away from it. Data on the type, number and physical characteristics of Anopheles larval breeding habitat, species composition and densities of anopheles mosquitoes in and around the study villages were investigated and recorded. Meteorological and reservoir water level data were compared with availability of Anopheles larval breeding sites and densities. Entomological data from the weekly larval collections showed that Anopheles pharoensis Theobald, Anopheles gambiae s.l. Giles, Anopheles coustani Laveran and Anopheles squamosus Theobald were breeding in the study area. The mean larval density of A. gambiae s.l. in this study was higher in slightly turbid and shallow aquatic habitats than in turbid and relatively deep aquatic habitats (F=16.97, pAnopheles larvae with water temperature of the breeding habitat and daily minimum atmospheric temperature (r=0.541, pAnopheles larval count, and the density of Anopheles mosquitoes in the vicinity. The proliferation of suitable breeding habitats around the reservoir villages is strongly associated with reservoir water level changes. This is particularly important for A. pharoensis and A. arabiensis which are important vectors of malaria in the area. Further investigation on the species diversity, physical and chemical habitat characteristics and impact of water holding capacity of the soil need to be done to generate detailed baseline data which will serve as a basis for proper water management activities for malaria risk mitigation.
Teklu, B. M.; Tekie, H.; McCartney, M.; Kibret, S.
Full Text Available Abstract Background Larval control is of paramount importance in the reduction of vector populations. Previous observations have suggested that, larvae of Anopheles gambiae s.l occur more often in small temporary habitats while other studies showed that long-lasting stable habitats are more productive than unstable habitats. In addition, the physical and biological conditions and stability of larval habitats can change rapidly in natural conditions. Therefore, we examined the effect of larval habitat age on productivity, larval survival and oviposition preference of Anopheles gambiae. Methods We sampled the three different habitat ages (10, 20 and 30?days on a daily basis for a period of six months to determine mosquito larval abundance. In addition, we tested the effect of age of water (habitat age on the oviposition choice preference of An. gambiae, larval development time and survivorship, and wing lengths of emerging adults. Additionally, chlorophyll a and abundance of mosquito larval predators in these habitats were monitored. Results Anopheles gambiae s.l. larvae were significantly more abundant (P=0.0002 in habitats that were cleared every 10?days compared to the other habitats. In particular, there were 1.7 times more larvae in this habitat age compared to the ones that were cleared every 30?days. There were significantly (PAn. gambiae in the different habitat ages was statistically insignificant (P>0.05. Conclusion The current study confirmed that age of the habitat significantly influences the productivity of malaria vectors in western Kenya highlands. Given that malaria vectors were found in all habitats with varying ages of water, simple environmental methods of maintaining the drainage ditches in the valley bottoms can help reduce larval abundance of malaria vectors. Such inexpensive methods of controlling mosquito breeding could be promoted to supplement other vector control methods, especially in areas where scarce resources are available for intensive mosquito control.
Adult Aedes aegypti (Linnaeus) (Diptera: Culicidae) were previously recovered from emergence traps on septic tanks in southeastern Puerto Rico. In this study we quantified immature mosquito abundance and its relationship with structural variables of the septic tanks and chemical properties of the water containing raw sewage. A miniaturized floating funnel trap was used to sample 89 septic tanks for larvae in the Puerto Rican community of Playa-Playita. Aedes aegypti larvae were recovered from 18% of the sampled tanks (10.3 larvae per septic tank per day). Larval presence was positively associated with cracking of the septic tank walls and uncovered access ports. Larval abundance was positively associated with cracking of the septic tank walls and larger tank surface areas, and inversely associated with the total dissolved solids (TDS). Culex quinquefasciatus (Say) larvae were also recovered from 74% of the septic tanks (129.6 larvae per septic tank per day). Larval presence was negatively associated with TDS in the water and larval abundance was positively associated with cracking of the septic tank walls. A screened, plastic emergence trap was used to sample 93 septic tanks within the community for Ae. aegypti and Cx. quinquefasciatus adults. Aedes aegypti adults were recovered from 49% of the sampled tanks (8.7 adults per septic tank per day) and Cx. quinquefasciatus adults were recovered from 97% of the sampled tanks (155.5 adults per septic tank per day). Aedes aegypti adult presence was positively associated with cracking, uncapped openings and septic water pH. The Ae. aegypti adult counts were positively associated with cracking and inversely associated with TDS and conductivity. This study marks the first published record of the recovery of Ae. aegypti larvae from holding tanks containing raw sewage in the Caribbean region. Our study indicates that Ae. aegypti larvae are present in sewage water and that septic tanks have at least the potential to maintain dengue transmission during the dry season. PMID:20374477
Burke, R; Barrera, R; Lewis, M; Kluchinsky, T; Claborn, D
A large proportion of mosquito larval habitats in urban and rural communities in sub-Saharan Africa are man-made. Therefore, community-based larval source management (LSM) could make a significant contribution to malaria control in an integrated vector management approach. Here we implemented an exploratory study to assess malaria prevalence and people's knowledge, attitudes and practices on malaria transmission, its control and the importance of man-made aquatic habitats for the development of disease vectors in one peri-urban lowland and two rural highland communities in western Kenya. We implemented monthly cross-sectional malaria surveys and administered a semi-structured questionnaire in 90 households, i.e. 30 households in each locality. Malaria prevalence was moderate (3.2-6.5%) in all sites. Nevertheless, residents perceived malaria as their major health risk. Thirty-two percent (29/90) of all respondents did not know that mosquitoes are responsible for the transmission of malaria. Over two-thirds (69/90) of the respondents said that mosquito breeding site could be found close to their homes but correct knowledge of habitat characteristics was poor. Over one-third (26/67) believed that immature mosquitoes develop in vegetation. Man-made pools, drainage channels and burrow pits were rarely mentioned. After explaining where mosquito larvae develop, 56% (50/90) felt that these sites were important for their livelihood. Peri-urban residents knew more about mosquitoes' role in malaria transmission, could more frequently describe the larval stages and their breeding habitats, and were more likely to use bed nets even though malaria prevalence was only half of what was found in the rural highland sites (pbased programs that take people's needs into account. Innovative, community-based training programs need to be developed to increase people's awareness of man-made vector breeding sites and acceptable control methods need to be designed in collaboration with the communities. PMID:20399739
Imbahale, S S; Fillinger, U; Githeko, A; Mukabana, W R; Takken, W
Mosquito were surveyed (Nov. 2009 - March 2010) in El Ismailia Governorate. Nine species were reported: Culex pipiens, Cx. perexiguus, Cx. antennatus, Anopheles tenebrosus, An. pharoensis, An. multicolor, Ochlerotatus detritus, Oc. caspius and Culiseta longiareolata. Culex pipiens was the predominant species (ca. 87% larvae and 57% adults). For the 3 common species, Cx. pipiens, Cx. perexiguus, and Cx. antennatus the following were examined: (1) the type and characteristics (temperature and pH) of the breeding habitats and their relation to the larval density and (2) the relation of adult indoor density to the indoor and outdoor temperature and RH. The abundance of mosquito vectors in El Ismailia with its old history of vector transmitted diseases contributes to the risk of mosquito borne disease transmission in this area. This would assist in the control activities. PMID:21980773
Abdel-Hamid, Yousrya M; Soliman, Mohamed I; Kenawy, Mohamed A
Successful management practices of avian populations depend on understanding relationships between birds and their habitat, especially in rare habitats, such as riparian areas of the desert Southwest. Remote-sensing technology has become popular in habitat modeling, but most of these models focus on single species, leaving their applicability to understanding broader community structure and function largely untested. We investigated the usefulness of two Normalized Difference Vegetation Index (NDVI) habitat models to model avian abundance and species richness on the upper San Pedro River in southeastern Arizona. Although NDVI was positively correlated with our bird metrics, the amount of explained variation was low. We then investigated the addition of vegetation metrics and other remote-sensing metrics to improve our models. Although both vegetation metrics and remotely sensed metrics increased the power of our models, the overall explained variation was still low, suggesting that general avian community structure may be too complex for NDVI models.
McFarland, Tiffany Marie; van Riper, Charles, III
Full Text Available Abstract Background Preventing malaria by controlling mosquitoes in their larval stages requires regular sensitive monitoring of vector populations and intervention coverage. The study assessed the effectiveness of operational, community-based larval habitat surveillance systems within the Urban Malaria Control Programme (UMCP in urban Dar es Salaam, Tanzania. Methods Cross-sectional surveys were carried out to assess the ability of community-owned resource persons (CORPs to detect mosquito breeding sites and larvae in areas with and without larviciding. Potential environmental and programmatic determinants of habitat detection coverage and detection sensitivity of mosquito larvae were recorded during guided walks with 64 different CORPs to assess the accuracy of data each had collected the previous day. Results CORPs reported the presence of 66.2% of all aquatic habitats (1,963/2,965, but only detected Anopheles larvae in 12.6% (29/230 of habitats that contained them. Detection sensitivity was particularly low for late-stage Anopheles (2.7%, 3/111, the most direct programmatic indicator of malaria vector productivity. Whether a CORP found a wet habitat or not was associated with his/her unfamiliarity with the area (Odds Ratio (OR [95% confidence interval (CI] = 0.16 [0.130, 0.203], P Conclusions Accessibility of habitats in urban settings presents a major challenge because the majority of compounds are fenced for security reasons. Furthermore, CORPs under-reported larvae especially where larvicides were applied. This UMCP system for larval surveillance in cities must be urgently revised to improve access to enclosed compounds and the sensitivity with which habitats are searched for larvae.
Oxidative stress (i.e., more oxidants than antioxidants) has been proposed as a proximate currency in life-history trade-offs, which if studied in an ecological setting allow a more realistic perspective on the origin and evolution of trade-offs. Therefore, the aim here was to investigate the impact of ecological and individual factors for variation in markers of oxidative stress using both experimental and correlational data. Total glutathione (tGSH), oxidized glutathione (GSSG), plasma antioxidant capacity (OXY), and plasma-reactive oxygen metabolites (ROM) were measured in more than 700 breeding great tits (Parus major). The main results revealed a pronounced sex difference, with females having lower ROM and OXY, but higher tGSH compared with males. In addition, birds breeding in the evergreen areas had higher tGSH compared with those in the deciduous habitat, but the experimentally manipulated breeding density had no significant effect on any of the redox markers. Independent of the sex differences, the larger the reproductive investment the lower the ROM of both males and females. Taken together, the extracellular markers - ROM and OXY - revealed similar results and were highly correlated. Interestingly, the direction of their effects was in the opposite direction to the endogenously synthesized tGSH and GSSG. This highlights the need to combine extracellular markers with endogenously synthesized antioxidants to understand its implications for the origin and evolution of trade-offs in an ecological setting. Oxidative stress has been proposed as a proximate currency in life-history trade-offs, which if studied in an ecological setting allow a more realistic perspective on the origin and evolution of trade-offs. Here multiple markers of oxidative stress were analysed in wild great tits. The results reveal that the endogenously synthesized antioxidant glutathione and markers of plasma oxidative stress are affected in opposing directions with regard to sex, habitat type, and spring date. Clutch size was negatively associated with oxidative damage, which suggests that those with high reproductive investment can combat physiological costs linked to oxidative stress. The experimentally manipulated breeding density did not influence oxidative stress physiology. The study highlights the need to measure multiple markers to understand the role of oxidative stress in limiting the expression of life-history traits and trajectories in different ecological contexts. PMID:24567835
Full Text Available Global climate change can potentially increase the transmission of mosquito vector-borne diseases such as malaria, lymphatic filariasis and dengue in many parts of the world. These predictions are based on the effects of changing temperature, rainfall and humidity on mosquito breeding and survival, the more rapid development of ingested pathogens in mosquitoes and the more frequent blood feeds at moderately higher ambient temperatures. An expansion of saline and brackish water bodies (water with <0.5 ppt or parts per thousand, 0.5–30 ppt and >30 ppt salt are termed fresh, brackish and saline respectively will also take place as a result of global warming causing a rise in sea levels in coastal zones. Its possible impact on the transmission of mosquito-borne diseases has, however, not been adequately appreciated. The relevant impacts of global climate change on the transmission of mosquito-borne diseases in coastal zones are discussed with reference to the Ross-McDonald equation and modeling studies. Evidence is presented to show that an expansion of brackish water bodies in coastal zones can increase densities of salinity-tolerant mosquitoes like Anopheles sundaicus and Culex sitiens, and lead to the adaptation of fresh water mosquito vectors like Anopheles culicifacies, Anopheles stephensi, Aedes aegypti and Aedes albopictus to salinity. Rising sea levels may therefore act synergistically with global climate change to increase the transmission of mosquito-borne diseases in coastal zones. Greater attention therefore needs to be devoted to monitoring disease incidence and preimaginal development of vector mosquitoes in artificial and natural coastal brackish/saline habitats. It is important that national and international health agencies are aware of the increased risk of mosquito-borne diseases in coastal zones and develop preventive and mitigating strategies. Application of appropriate counter measures can greatly reduce the potential for increased coastal
Background Malaria vector control strategies that target adult female mosquitoes are challenged by the emergence of insecticide resistance and behavioural resilience. Conventional larviciding is restricted by high operational costs and inadequate knowledge of mosquito-breeding habitats in rural settings that might be overcome by the juvenile hormone analogue, Pyriproxyfen (PPF). This study assessed the potential for Anopheles arabiensis to pick up and transfer lethal doses of PPF from contamination sites to their breeding habitats (i.e. autodissemination of PPF). Methods A semi-field system (SFS) with four identical separate chambers was used to evaluate PPF-treated clay pots for delivering PPF to resting adult female mosquitoes for subsequent autodissemination to artificial breeding habitats within the chambers. In each chamber, a tethered cow provided blood meals to laboratory-reared, unfed female An. arabiensis released in the SFS. In PPF-treated chambers, clay pot linings were dusted with 0.2 – 0.3 g AI PPF per pot. Pupae were removed from the artificial habitats daily, and emergence rates calculated. Impact of PPF on emergence was determined by comparing treatment with an appropriate control group. Results Mean (95% CI) adult emergence rates were (0.21?±?0.299) and (0.95?±?0.39) from PPF-treated and controls respectively (p?0.0001). Laboratory bioassay of water samples from artificial habitats in these experiments resulted in significantly lower emergence rates in treated chambers (0.16?±?0.23) compared to controls 0.97?±?0.05) (p?0.0001). In experiments where no mosquitoes introduced, there were no significant differences between control and treatment, indicating that transfer of PPF to breeding sites only occurred when mosquitoes were present; i.e. that autodissemination had occurred. Treatment of a single clay pot reduced adult emergence in six habitats to (0.34?±?0.13) compared to (0.98?±?0.02) in the controls (p?0.0001), showing a high level of habitats coverage amplification of the autodissemination event. Conclusion The study provides proof of principle for the autodissemination of PPF to breeding habitats by malaria vectors. These findings highlight the potential for this technique for outdoor control of malaria vectors and call for the testing of this technique in field trials.
Malaria is associated with dams because their reservoirs provide mosquitoes, the vector of malaria, with permanent breeding sites. The risk of contracting malaria is likely to be enhanced following the increasing trend of hydropower dam construction to satisfy the expanding energy needs in developing countries. A close examination of its adverse health impacts is critical in the design, construction, and operation phases. We will present results of extensive field studies in 2012 and 2013 around the Koka Reservoir, Ethiopia. The results uncover the importance of reservoir management especially after the rainy seasons. Furthermore, we show the capability of a newly modified hydrology, entomology and malaria transmission simulator, HYDREMATS (Bomblies et al, 2008), and its potential as a tool for evaluating environmental management strategies to control malaria. HYDREMATS was developed to represent how the hydrology in nearby villages is impacted by the reservoir system, and the role of different types of vector ecologies associated with different Anopheles mosquito species. The hydrology component of HYDREMATS simulates three different mosquito breeding habitats: rain-fed pools, groundwater pools, and shoreline water. The entomology component simulates the life cycles of An. funestus and An. arabiensis, the two main vectors around the reservoir. The model was calibrated over the 2012-2013 period. The impact of reservoir water level management on the mosquito population is explored based on numerical model simulations and field experiments.
Endo, N.; Eltahir, E. A.
Wetlands are valuable habitats that provide important social, economic, and ecological services such as flood control, water quality improvement, carbon sequestration, pollutant removal, and primary/secondary production export to terrestrial and aquatic food chains. There is disagreement about the need for mosquito control in wetlands and about the techniques utilized for mosquito abatement and their impacts upon wetlands ecosystems. Mosquito control in wetlands is a complex issue influenced ...
Full Text Available Abstract Background As the population of Africa rapidly urbanizes it may be possible to protect large populations from malaria by controlling aquatic stages of mosquitoes. Here we present a baseline evaluation of the ability of community members to detect mosquito larval habitats with minimal training and supervision in the first weeks of an operational urban malaria control program. Methods The Urban Malaria Control Programme of Dar es Salaam recruited and provided preliminary training to teams of Community-Owned Resource Persons (CORPs who performed weekly surveys of mosquito breeding sites. Two trained mosquito biologists accompanied each of these teams for one week and evaluated the sensitivity of this system for detecting potential Anopheles habitats. Results Overall, 42.4% of 986 habitats surveyed by an inspection team had previously been identified by CORPs. Agricultural habitats were detected less often than other habitats (30.8% detected, Odds Ratio [95%CI] = 0.46 [0.29–0.73], P = 0.001. Non-agricultural artificial habitats were less suitable than other habitats (29.3% occupancy, OR = 0.69 [0.46–1.03], P = 0.066 but still constituted 45% (169/289 of occupied habitats because of their abundance (51 % of all habitats. Conclusion The levels of coverage achieved by modestly trained and supported CORPs at the start of the Dar es Salaam UMCP were insufficient to enable effective suppression of malaria transmission through larval control. Further operational research is required to develop surveillance systems that are practical, affordable, effective and acceptable so that community-based integrated vector management can be implemented in cities across Africa.
Wyoming big sagebrush ( Artemisia tridentata wyomingensis A. t. Nutt. ssp. wyomingensis Beetle and Young) communities provide structure and forbs and insects needed by greater sage-grouse ( Centrocercus urophasianus) for growth and survival. We evaluated forb, insect, and soil responses at six mowed and 19 prescribed burned sites compared to 25, paired and untreated reference sites. Sites were classified by treatment type, soil type, season, and decade of treatment (sites burned during 1990-1999 and sites burned or mowed during 2000-2006). Our objective was to evaluate differences in ten habitat attributes known to influence sage-grouse nesting and brood rearing to compare responses among treatment scenarios. Contrary to desired outcomes, treating Wyoming big sagebrush through prescribed burning or mowing may not stimulate cover or increase nutrition in food forbs, or increase insect abundance or indicators of soil quality compared with reference sites. In some cases, prescribed burning showed positive results compared with mowing such as greater forb crude protein content (%), ant (Hymenoptera; no./trap), beetle (Coleoptera/no./trap), and grasshopper abundance (Orthoptera; no./sweep), and total (%) soil carbon and nitrogen, but of these attributes, only grasshopper abundance was enhanced at burned sites compared with reference sites in 2008. Mowing did not promote a statistically significant increase in sage-grouse nesting or early brood-rearing habitat attributes such as cover or nutritional quality of food forbs, or counts of ants, beetles, or grasshoppers compared with reference sites.
Hess, Jennifer E.; Beck, Jeffrey L.
Alguns aspectos da ecologia dos mosquitos (Diptera, Culicidae de uma área de planície (granjas Calábria, em Jacarepaguá, Rio de Janeiro: V. Criadouros Some aspects of the ecology of mosquitoes (Diptera, Culicidae of an area of plains (granjas Calábria, in Jacarepaguá, Rio de Janeiro: V. Breeding places
Full Text Available Apresentamos os resultados de observações sobre os criadouros dos mosquitos, que realizamos numa fazenda - Granjas Calábria, da Baixada de Jacarepaguá, Rio de Janeiro, no período de agosto de 1981 a julho de 1983. A maioria das espécies locais preferiu coleções líquidas no solo, particularmente as de caráter natural, não deixando, entretanto, de procurar aquelas propiciadas pelas atividades humanas. Os criadouros transitórios foram mais freqüentados por Culex saltanensis e pelas espécies da tribo Aedini, como Aedes scapularis, Aedes taeniorhynchus, Psorophora ciliata e Psorophora confinnis, enquanto os de caráter permanente foram mananciais de formas imaturas de Mansonia titillans, Culex amazonensis, Culex chidesteri, Culex bidens, Culex declarator, Culex nigripalpus e Culex plectoporpe. Algumas espécies foram coletadas em recipientes naturais: Culex ocellatus, os Culex (Microculex, Phoniomyia davisi, Phoniomyia deanei e Wyeomyia forcipenis, em bromélias; Aedes terrens, Culex gairus e Culex imitador, em buraco em árvore; e Wyeomyia leucostigma, em axilas submersas das folhas de taboas (Thypha dominguensis. Culex gairus foi encontrado pela primeira vez criando em recipientes artificiais, locais também preferidos por Culex corniger, Culex quinquefasciatus e Limatus durhami.Results are presented of observations on the breeding places of mosquitoes, carried out in a coastal lowland farm - Granjas Calábria, in JAcarepaguá, city of Rio de Janeiro, Brazil. The majority of species preferred breeding places on the ground, chiefly the natural ones, but also developed in those originated from human activities. Cx. saltanensis and the species belonging to the Aedini tribe, such as Ae. scapularis, Ae. taeniorhynchus, Ps. ciliata, Ps. confinnis and Ps. Pseudomelanota were more abundant in temporary breeding places, while Ma. titillans, Cx. amazonensis, Cx. chidesteri, Cx. bidens, Cx. declarator, cx. nigipalpus and Cx. plectoporpe occurred usually in the permanent ones. Some species were collected in natural recipients: Cx. ocellatus, the Cx. (Microculex, Ph davisi, Ph. deanei and Wy. forcipenis, in bromeliads, Ae. terrens, Cx. imitator and Cx. gairus, in tree-holes; and Wy. leucostigma, in the submerged Typha dominguensis leaf axils. Cx. gairus was found for the first time breeding in artificial containers, which were also preferred by Cx. corniger, Cx. quinquefasciatus and Li. durhaml.
Alguns aspectos da ecologia dos mosquitos (Diptera, Culicidae) de uma área de planície (granjas Calábria), em Jacarepaguá, Rio de Janeiro: V. Criadouros / Some aspects of the ecology of mosquitoes (Diptera, Culicidae) of an area of plains (granjas Calábria), in Jacarepaguá, Rio de Janeiro: V. Breeding places
Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Apresentamos os resultados de observações sobre os criadouros dos mosquitos, que realizamos numa fazenda - Granjas Calábria, da Baixada de Jacarepaguá, Rio de Janeiro, no período de agosto de 1981 a julho de 1983. A maioria das espécies locais preferiu coleções líquidas no solo, particularmente as d [...] e caráter natural, não deixando, entretanto, de procurar aquelas propiciadas pelas atividades humanas. Os criadouros transitórios foram mais freqüentados por Culex saltanensis e pelas espécies da tribo Aedini, como Aedes scapularis, Aedes taeniorhynchus, Psorophora ciliata e Psorophora confinnis, enquanto os de caráter permanente foram mananciais de formas imaturas de Mansonia titillans, Culex amazonensis, Culex chidesteri, Culex bidens, Culex declarator, Culex nigripalpus e Culex plectoporpe. Algumas espécies foram coletadas em recipientes naturais: Culex ocellatus, os Culex (Microculex), Phoniomyia davisi, Phoniomyia deanei e Wyeomyia forcipenis, em bromélias; Aedes terrens, Culex gairus e Culex imitador, em buraco em árvore; e Wyeomyia leucostigma, em axilas submersas das folhas de taboas (Thypha dominguensis). Culex gairus foi encontrado pela primeira vez criando em recipientes artificiais, locais também preferidos por Culex corniger, Culex quinquefasciatus e Limatus durhami. Abstract in english Results are presented of observations on the breeding places of mosquitoes, carried out in a coastal lowland farm - Granjas Calábria, in JAcarepaguá, city of Rio de Janeiro, Brazil. The majority of species preferred breeding places on the ground, chiefly the natural ones, but also developed in those [...] originated from human activities. Cx. saltanensis and the species belonging to the Aedini tribe, such as Ae. scapularis, Ae. taeniorhynchus, Ps. ciliata, Ps. confinnis and Ps. Pseudomelanota were more abundant in temporary breeding places, while Ma. titillans, Cx. amazonensis, Cx. chidesteri, Cx. bidens, Cx. declarator, cx. nigipalpus and Cx. plectoporpe occurred usually in the permanent ones. Some species were collected in natural recipients: Cx. ocellatus, the Cx. (Microculex), Ph davisi, Ph. deanei and Wy. forcipenis, in bromeliads, Ae. terrens, Cx. imitator and Cx. gairus, in tree-holes; and Wy. leucostigma, in the submerged Typha dominguensis leaf axils. Cx. gairus was found for the first time breeding in artificial containers, which were also preferred by Cx. corniger, Cx. quinquefasciatus and Li. durhaml.
Lourenço-de-Oliveira, Ricardo; Heyden, Rosemarie; Silva, Teresa Fernandes da.
Full Text Available Entomological studies to determine the effect of the physical characteristics of larval breeding water bodies and reservoir water level changes on the occurrence of Anopheles mosquito larvae and on the spatial and temporal formation of larval breeding habitats were conducted in two villages at Koka reservoir between August and December 2007. Of the two study villages, Ejersa is in close proximity to the reservoir, and Kuma is 5 km away from it. Data on the type, number and physical characteristics of Anopheles larval breeding habitat, species composition and densities of anopheles mosquitoes in and around the study villages were investigated and recorded. Meteorological and reservoir water level data were compared with availability of Anopheles larval breeding sites and densities. Entomological data from the weekly larval collections showed that Anopheles pharoensis Theobald, Anopheles gambiae s.l. Giles, Anopheles coustani Laveran and Anopheles squamosus Theobald were breeding in the study area. The mean larval density of A. gambiae s.l. in this study was higher in slightly turbid and shallow aquatic habitats than in turbid and relatively deep aquatic habitats (F=16.97, pF=6.03, pA. pharoensis in habitat with floating vegetation and with relatively shady conditions was significantly higher than that of less shaded aquatic habitat and greater emergent vegetation (F=15.75, pF=10.56, pAnopheles larvae with water temperature of the breeding habitat and daily minimum atmospheric temperature (r=0.541, pr=0.604, pr=0.605, pAnopheles larval count, and the density of Anopheles mosquitoes in the vicinity. The proliferation of suitable breeding habitats around the reservoir villages is strongly associated with reservoir water level changes. This is particularly important for A. pharoensis and A. arabiensis which are important vectors of malaria in the area. Further investigation on the species diversity, physical and chemical habitat characteristics and impact of water holding capacity of the soil need to be done to generate detailed baseline data which will serve as a basis for proper water management activities for malaria risk mitigation.
Wetlands are valuable habitats that provide important social, economic, and ecological services such as flood control, water quality improvement, carbon sequestration, pollutant removal, and primary/secondary production export to terrestrial and aquatic food chains. There is disagreement about the need for mosquito control in wetlands and about the techniques utilized for mosquito abatement and their impacts upon wetlands ecosystems. Mosquito control in wetlands is a complex issue influenced by numerous factors, including many hard to quantify elements such as human perceptions, cultural predispositions, and political climate. In spite of considerable progress during the last decades, habitat protection and environmentally sound habitat management still remain inextricably tied to politics and economics. Furthermore, the connections are often complex, and occur at several levels, ranging from local businesses and politicians, to national governments and multinational institutions. Education is the key to lasting wetlands conservation. Integrated mosquito abatement strategies incorporate many approaches and practicable options, as described herein, and need to be well-defined, effective, and ecologically and economically sound for the wetland type and for the mosquito species of concern. The approach will certainly differ in response to disease outbreaks caused by mosquito-vectored pathogens versus quality of life issues caused by nuisance-biting mosquitoes. In this contribution, we provide an overview of the ecological setting and context for mosquito control in wetlands, present pertinent information on wetlands mosquitoes, review the mosquito abatement options available for current wetlands managers and mosquito control professionals, and outline some necessary considerations when devising mosquito control strategies. Although the emphasis is on North American wetlands, most of the material is applicable to wetlands everywhere. PMID:23222252
Rey, Jorge R; Walton, William E; Wolfe, Roger J; Connelly, C Roxanne; O'Connell, Sheila M; Berg, Joe; Sakolsky-Hoopes, Gabrielle E; Laderman, Aimlee D
Full Text Available Wetlands are valuable habitats that provide important social, economic, and ecological services such as flood control, water quality improvement, carbon sequestration, pollutant removal, and primary/secondary production export to terrestrial and aquatic food chains. There is disagreement about the need for mosquito control in wetlands and about the techniques utilized for mosquito abatement and their impacts upon wetlands ecosystems. Mosquito control in wetlands is a complex issue influenced by numerous factors, including many hard to quantify elements such as human perceptions, cultural predispositions, and political climate. In spite of considerable progress during the last decades, habitat protection and environmentally sound habitat management still remain inextricably tied to politics and economics. Furthermore, the connections are often complex, and occur at several levels, ranging from local businesses and politicians, to national governments and multinational institutions. Education is the key to lasting wetlands conservation. Integrated mosquito abatement strategies incorporate many approaches and practicable options, as described herein, and need to be well-defined, effective, and ecologically and economically sound for the wetland type and for the mosquito species of concern. The approach will certainly differ in response to disease outbreaks caused by mosquito-vectored pathogens versus quality of life issues caused by nuisance-biting mosquitoes. In this contribution, we provide an overview of the ecological setting and context for mosquito control in wetlands, present pertinent information on wetlands mosquitoes, review the mosquito abatement options available for current wetlands managers and mosquito control professionals, and outline some necessary considerations when devising mosquito control strategies. Although the emphasis is on North American wetlands, most of the material is applicable to wetlands everywhere.
Gabrielle E. Sakolsky-Hoopes
To date around 3500 different species of mosquito have been described, several tens of which are vectors of pathogens of remarkable interest in public health. Mosquitoes are present all around the world showing a great ability to adapt to very different types of habitats where they play relevant ecological roles. It is very likely that components of the mosquito microbiota have given the mosquito a great capacity to adapt to different environments. Current advances in understanding the mosqui...
Ricci, Irene; Damiani, Claudia; Capone, Aida; Defreece, Chenoa; Rossi, Paolo; Favia, Guido
Trichomycete fungi (Zygomycota) associated with mosquito larvae (Diptera: Culicidae) in natural and artificial habitats in Manaus, AM Brazil / Fungos Trichomycetes (Zygomicota) associados com larvas de mosquitos (Diptera: Culicidae) em criadouros naturais e artificiais em Manaus, AM
Full Text Available SciELO Brazil | Language: English Abstract in portuguese Espécies de fungos da classe Trichomycete (Zygomycota) estão associados com o trato digestivo dos Arthropoda. A relação entre esses fungos e seus hospedeiros ainda é pouco conhecida, podendo ser comensal, benéfica ou deletéria. Conhecimentos da estrutura de comunidades parasitas/ patógenos e os habi [...] tats de larvas de Culicidae podem ser importantes em estudos que utilizam medidas combinadas para o controle populacional. Larvas de Culicidae e os fungos Trichomycetes associados foram coletados no município de Manaus, AM; amostras de criadouros incluindo plantas (habitat natural) e reservatórios antrópicos (habitat artificial). O total de 1518 larvas foi coletado, 913 em criadouros naturais e 605 em criadouros artificiais, distribuídas em 12 espécies de sete gêneros. O total de 661 indivíduos (4° estádio) foi dissecado para verificar a presença de fungos Trichomycetes no intestino médio e posterior. Infecção de fungos Trichomycetes no intestino posterior foram observados em 15% de Culex urichii Coquillett, 13% de Culex (Culex) sp1, 9% of Limatus spp., 49% de Aedes aegypti Linnaeus e 1% de Ochlerotatus argyrothorax Bonne-Wepster & Bonne. Somente em Ae. aegypti foram observados fungos Trichomycetes na matriz peritrófica, no intestino médio; porém este fato é provavelmente, um resultado de um desenvolvimento anormal deste fungo. Abstract in english Fungal species of the class Trichomycete fungi (Zygomycota) are associated with the digestive tracts of Arthropoda. The relationships between these fungi and their hosts are still little understood: they may be commensal, beneficial or deleterious. Knowledge of the community structure of parasites/ [...] pathogens and of the habitats of each species of Culicidae larvae can be important in studies that intend to use combined approaches to population control. Larvae of Culicidae and their associated trichomycete fungi were collected in Manaus County, AM, Brazil; sampling habitats included plants (natural habitat) and anthropic containers (artificial habitats). The total of 1,518 larvae were collected, 913 of which were in natural habitats and 605 were in artificial habitats, distributed in 12 species of seven genera. The total of 661 individuals (4th instar) were dissected to verify the presence of trichomycete fungi in the mid and hindgut. Infection of trichomycete fungi in the hindgut was observed in 15% of Culex urichii Coquillett, 13% of Culex (Culex) sp1, 9% of Limatus spp., 49% of Aedes aegypti Linnaeus and 1% of Ochlerotatus argyrothorax Bonne-Wepster & Bonne. Only in Ae. aegypti were trichomycete fungi observed in the peritrophic matrix, in the midgut; however, this fact is probably, a result of abnormal development of the fungi.
Pereira, Eleny da S.; Ferreira, Ruth L.M.; Hamada, Neusa; Lichtwardt, Robert W..
Mosquitoes were surveyed over one year period in two localities in Cairo representing different levels of urban planning: El-Muqattam (planned) and Abu-Seir (unplanned). Culex pipiens, Cx. perexiguus, Cx. pusillus, Ochlerotatus caspius, Culiseta longiareolata and Anopheles multicolor were the collected species at both sites. Mosquitoes were more common in Abu-Seir than in El-Muqattam, with larvae of the filaria vector Cx. pipiens accounting for 81% and 52% of recorded individuals at these sites, respectively. Five types of the potential breeding habitats were detected of which, the cesspits (El-Muqattam) and drainage canals (Abu-Seir) were the most common while springs in El-Muqattam and drainage canals in Abu-Seir were the most productive types. Both Cx. pipiens and Cx. perexiguus bred year round with peaks of abundance coinciding with higher temperatures. PMID:22662608
Ammar, Sherif E; Kenawy, Mohamed A; Abdel-Rahman, Hashim A; Gad, Adel M; Hamed, Adel F
Phlebotomine sand flies transmit Leishmania, phlebo-viruses and Bartonella to humans. A prominent gap in our knowledge of sand fly biology remains the ecology of their immature stages. Sand flies, unlike mosquitoes do not breed in water and only small numbers of larvae have been recovered from diverse habitats that provide stable temperatures, high humidity and decaying organic matter. We describe studies designed to identify and characterize sand fly breeding habitats in a Judean Desert focus of cutaneous leishmaniasis. To detect breeding habitats we constructed emergence traps comprising sand fly-proof netting covering defined areas or cave openings. Large size horizontal sticky traps within the confined spaces were used to trap the sand flies. Newly eclosed male sand flies were identified based on their un-rotated genitalia. Cumulative results show that Phlebotomus sergenti the vector of Leishmania tropica rests and breeds inside caves that are also home to rock hyraxes (the reservoir hosts of L. tropica) and several rodent species. Emerging sand flies were also trapped outside covered caves, probably arriving from other caves or from smaller, concealed cracks in the rocky ledges close by. Man-made support walls constructed with large boulders were also identified as breeding habitats for Ph. sergenti albeit less important than caves. Soil samples obtained from caves and burrows were rich in organic matter and salt content. In this study we developed and put into practice a generalized experimental scheme for identifying sand fly breeding habitats and for assessing the quantities of flies that emerge from them. An improved understanding of sand fly larval ecology should facilitate the implementation of effective control strategies of sand fly vectors of Leishmania.
Moncaz, Aviad; Faiman, Roy; Kirstein, Oscar; Warburg, Alon
A review and synthesis of existing information were used to develop models for breeding and wintering habitats for the wood duck (Aix sponsa). The models are scaled to produce indices of habitat suitability between 0 (unsuitable habitat) and 1 (optimally ...
P. J. Sousa A. H. Farmer
Trichomycete fungi (Zygomycota) associated with mosquito larvae (Diptera: Culicidae) in natural and artificial habitats in Manaus, AM Brazil Fungos Trichomycetes (Zygomicota) associados com larvas de mosquitos (Diptera: Culicidae) em criadouros naturais e artificiais em Manaus, AM
Fungal species of the class Trichomycete fungi (Zygomycota) are associated with the digestive tracts of Arthropoda. The relationships between these fungi and their hosts are still little understood: they may be commensal, beneficial or deleterious. Knowledge of the community structure of parasites/ pathogens and of the habitats of each species of Culicidae larvae can be important in studies that intend to use combined approaches to population control. Larvae of Culicidae and their associated ...
Pereira, Eleny Da S.; Ferreira, Ruth L. M.; Neusa Hamada; Lichtwardt, Robert W.
Full Text Available Background & objectives: An environmental friendly formulation Starycide 480 SC (Triflumuron–OMS-2015 , a new insect growth regulator with chitin synthesis inhibitor type mode of action wasevaluated against mosquito larvae in laboratory and small-scale field trials carried out in and aroundDelhi.Methods: The formulation was tested in laboratory for its bio-efficacy against late III instar mosquitolarvae of different species using WHO bioassay procedure. In the field formulation was sprayed atdoses of 0.3, 0.5 and 1 ppm (g/m3 in the natural breeding habitats of Anopheles and Culex mosquitoes.The impact was assessed by monitoring densities of larvae by dipper and observing the reductionin larval density and inhibition of adult emergence.Results: In the laboratory, formulation was more effective against larvae of Anopheles stephensi andAedes aegypti than Culex quinquefasciatus, but it produced 100% inhibition of adult emergence forall mosquito species at a concentration of 0.02 ppm. In the field trials, formulation did not produce100% reduction in the density of late stage larvae even at 1 ppm (g/m3, the highest dose tested, butit resulted in 100% inhibition of pupal formation of both Anopheles and Culex spp in different typesof habitats for 3–7 weeks even at a lower dose of 0.5 ppm.Interpretation & conclusion : Application of triflumuron in the natural breeding habitats in bothclean and polluted water @ 0.5 ppm (g/m3 resulted in complete inhibition of adult emergence of bothAnopheles and Culex spp for 3–7 weeks. This formulation may be tested in large-scale field trials forfurther use in the vector control programme.
C.P. Batra, P.K. Mittal, T. Adak & M.A. Ansari
In traditional vector surveillance systems, adult mosquito density and the rate of mosquito-human host contact are estimated from the mosquito numbers captured in mechanical traps. But the design of the traps, their placement in the habitat and operating time, microclimate, and other environmental factors bias mosquito responses such that trapped mosquito numbers may be at variance with the numbers actually making human contact. As an alternative to mechanical traps, direct measurement of landing mosquito density enables real-time estimation of the mosquito-human-host-contact parameter. Based on this paradigm, we studied methods to measure mosquito landing responses to a human host. Our results showed: (a) an 18% difference (Planding responses of Culex nigripalpus Theobald and Cx. quinquefasciatus Say with increased sampling time; (c) no difference (P>0.55) in the average number of Ae. albopictus landing on the arm (8.6±1.6min(-1)) compared with the leg (9.2±2.5min(-1)) of the same human subject; (d) differences among day-to-day landing patterns for the mosquito species we studied but measurable periodicity (Planding mosquito density from air temperature (Planding density on a human subject. PMID:24769003
Barnard, Donald R; Dickerson, Catherine Z; Murugan, Kadarkarai; Xue, Rui-De; Kline, Daniel L; Bernier, Ulrich R
To enable a better understanding of the overwhelming alterations in the invasive mosquito species (IMS), methodical insight into the population and environmental factors that govern the IMS and pathogen adaptations are essential. There are numerous ways of estimating mosquito populations, and usually these describe developmental and life-history parameters. The key population parameters that should be considered during the surveillance of invasive mosquito species are: (1) population size and dynamics during the season, (2) longevity, (3) biting behaviour, and (4) dispersal capacity. Knowledge of these parameters coupled with vector competence may help to determine the vectorial capacity of IMS and basic disease reproduction number (R0) to support mosquito borne disease (MBD) risk assessment. Similarly, environmental factors include availability and type of larval breeding containers, climate change, environmental change, human population density, increased human travel and goods transport, changes in living, agricultural and farming habits (e.g. land use), and reduction of resources in the life cycle of mosquitoes by interventions (e.g. source reduction of aquatic habitats). Human population distributions, urbanisation, and human population movement are the key behavioural factors in most IMS-transmitted diseases. Anthropogenic issues are related to the global spread of MBD such as the introduction, reintroduction, circulation of IMS and increased exposure to humans from infected mosquito bites. This review addresses the population and environmental factors underlying the growing changes in IMS populations in Europe and confers the parameters selected by criteria of their applicability. In addition, overview of the commonly used and newly developed tools for their monitoring is provided.
Full Text Available Abstract Background Although the occurrence of malaria vector larvae in the valleys of western Kenya highlands is well documented, knowledge of larval habitats in the uphill sites is lacking. Given that most inhabitants of the highlands actually dwell in the uphill regions, it is important to develop understanding of mosquito breeding habitat stability in these sites in order to determine their potential for larval control. Methods A total of 128 potential larval habitats were identified in hilltops and along the seasonal streams in the Sigalagala area of Kakamega district, western Kenya. Water availability in the habitats was followed up daily from August 3, 2006 to February 23, 2007. A habitat is defined as stable when it remains aquatic continuously for at least 12 d. Mosquito larvae were observed weekly. Frequencies of aquatic, stable and larvae positive habitats were compared between the hilltop and seasonal stream area using ?2-test. Factors affecting the presence/absence of Anopheles gambiae larvae in the highlands were determined using multiple logistic regression analysis. Results Topography significantly affected habitat availability and stability. The occurrence of aquatic habitats in the hilltop was more sporadic than in the stream area. The percentage of habitat occurrences that were classified as stable during the rainy season is 48.76% and 80.79% respectively for the hilltop and stream area. Corresponding frequencies of larvae positive habitats were 0% in the hilltop and 5.91% in the stream area. After the rainy season, only 23.42% of habitat occurrences were stable and 0.01% larvae positive habitats were found in the hilltops, whereas 89.75% of occurrences remained stable in the stream area resulting in a frequency of 12.21% larvae positive habitats. The logistic regression analysis confirmed the association between habitat stability and larval occurrence and indicated that habitat surface area was negatively affecting the occurrence of An. gambiae larvae. While An. gambiae and An. funestus larvae occurred throughout the study period along the streams, a total of only 15 An. gambiae larvae were counted in the hilltops, and no An. funestus were found. Moreover, no larvae managed to develop into adults in the hilltops, and the density of adult An. gambiae was consistently low, averaging at 0.06 females per house per survey. Conclusion The occurrence of malaria vector larvae in the hilltop area was uncommon as a result of the low availability and high instability of habitats. To optimize the cost-effectiveness of malaria interventions in the western Kenya highlands, larval control should be focused primarily along the streams, as these are likely the only productive habitats at high altitude.
Immatures of both Aedes aegypti and Aedes albopictus have been found in water-holding bromeliad axils in Brazil. Removal of these plants or their treatment with insecticides in public and private gardens have been undertaken during dengue outbreaks in Brazil despite uncertainty as to their importance as productive habitats for dengue vectors. From March 2005-February 2006, we sampled 120 randomly selected bromeliads belonging to 10 species in a public garden less than 200 m from houses in a d...
Mocellin, Ma?rcio Goulart; Simo?es, Tayna?na Ce?sar; Do Nascimento, Teresa Fernandes Silva; Teixeira, Maria Lucia Franc?a; Lounibos, Leon Philip; Oliveira, Ricardo Lourenc?o
Full Text Available Los mosquitos (Diptera: Culicidae son insectos holometábolos con estadios inmaduros acuáticos que utilizan una amplia variedad de hábitats larvales, desde cuerpos de agua en el suelo hasta Fitotelmata (depósitos de agua en las plantas y depósitos artificiales. La disponibilidad de sitios de reproducción a menudo determina el límite superior del ámbito de los mosquitos. Nosotros construimos una base de datos de 9 607 registros, 432 localidades, 19 géneros y 254 especies. La coordillera Andina posee el 77% de los registros con mayor altitud incluyendo Aedes euris con un registro a 3 300 m, seguido por tres especies de Anopheles -subgénero Kerteszia- con una altitud máxima de 2 680 m. Wyeomyia bicornis y Culex daumastocampa a 2 550 m fueron los registros de mayor altitud en la cordillera Costera- Central, mientras que el record más alto en Pantepui fue Wyeomyia zinzala a 2 252 m. El 60% de los registros de máxima altitud están representados por especies asociadas con fitotelmata (Bromeliaceae y Sarraceniaceae. Los límites superiores de Culex quinquefasciatus y Anopheles (Kerteszia podría representar el límite teórico para la transmisión de filariasis o arbovirus, por Culex y malaria por Anopheles (Kerteszia en Venezuela. Del mismo modo, un vector del dengue, Aedes aegypti, no ha sido registrado por encima de 2 000 m.Highest mosquito records (Diptera: Culicidae in Venezuela. Mosquitoes (Diptera: Culicidae are holometabolous insects with aquatic immature stages, which use a broad variety of larval habitats, from ground water bodies to Phytothelmata (water deposits in plants and artificial deposits. The availability of breeding sites often determines the upper limits of mosquito ranges. We built a database with 9 607 records with 432 localities, 19 genera and 254 species. The Andean mountains have 77% of the highest mosquito records including Aedes euris with record at 3 133 m, followed by three species of Anopheles -subgenera Kerteszia- with the upper limit of 2 680 m. Wyeomyia bicornis and Culex daumastocampa at 2 550 m were the highest records in the Central- Coastal cordillera, while the highest record in Pantepui was Wyeomyia zinzala at 2 252 m. The species associated with phytothelmata (Bromeliaceae and Sarraceniaceae represent 60% of the records. The upper limits of Culex quinquefasciatus and Anopheles (Kerteszia species could represent the theoretical limit for transmission of filariasis or arboviruses, by Culex, and malaria by Anopheles (Kerteszia in Venezuela. Similarly, a vector of Dengue, Aedes aegypti, has not been not recorded above 2 000 m. Rev. Biol. Trop. 58 (1: 245-254. Epub 2010 March 01.
Full Text Available SciELO Costa Rica | Language: Spanish Abstract in spanish Los mosquitos (Diptera: Culicidae) son insectos holometábolos con estadios inmaduros acuáticos que utilizan una amplia variedad de hábitats larvales, desde cuerpos de agua en el suelo hasta Fitotelmata (depósitos de agua en las plantas) y depósitos artificiales. La disponibilidad de sitios de reprod [...] ucción a menudo determina el límite superior del ámbito de los mosquitos. Nosotros construimos una base de datos de 9 607 registros, 432 localidades, 19 géneros y 254 especies. La coordillera Andina posee el 77% de los registros con mayor altitud incluyendo Aedes euris con un registro a 3 300 m, seguido por tres especies de Anopheles -subgénero Kerteszia- con una altitud máxima de 2 680 m. Wyeomyia bicornis y Culex daumastocampa a 2 550 m fueron los registros de mayor altitud en la cordillera Costera- Central, mientras que el record más alto en Pantepui fue Wyeomyia zinzala a 2 252 m. El 60% de los registros de máxima altitud están representados por especies asociadas con fitotelmata (Bromeliaceae y Sarraceniaceae). Los límites superiores de Culex quinquefasciatus y Anopheles (Kerteszia) podría representar el límite teórico para la transmisión de filariasis o arbovirus, por Culex y malaria por Anopheles (Kerteszia) en Venezuela. Del mismo modo, un vector del dengue, Aedes aegypti, no ha sido registrado por encima de 2 000 m. Abstract in english Highest mosquito records (Diptera: Culicidae) in Venezuela. Mosquitoes (Diptera: Culicidae) are holometabolous insects with aquatic immature stages, which use a broad variety of larval habitats, from ground water bodies to Phytothelmata (water deposits in plants) and artificial deposits. The availab [...] ility of breeding sites often determines the upper limits of mosquito ranges. We built a database with 9 607 records with 432 localities, 19 genera and 254 species. The Andean mountains have 77% of the highest mosquito records including Aedes euris with record at 3 133 m, followed by three species of Anopheles -subgenera Kerteszia- with the upper limit of 2 680 m. Wyeomyia bicornis and Culex daumastocampa at 2 550 m were the highest records in the Central- Coastal cordillera, while the highest record in Pantepui was Wyeomyia zinzala at 2 252 m. The species associated with phytothelmata (Bromeliaceae and Sarraceniaceae) represent 60% of the records. The upper limits of Culex quinquefasciatus and Anopheles (Kerteszia) species could represent the theoretical limit for transmission of filariasis or arboviruses, by Culex, and malaria by Anopheles (Kerteszia) in Venezuela. Similarly, a vector of Dengue, Aedes aegypti, has not been not recorded above 2 000 m. Rev. Biol. Trop. 58 (1): 245-254. Epub 2010 March 01.
Juan-Carlos, Navarro; Fabiola, Del Ventura; Adriana, Zorrilla; Jonathan, Liria.
The 2005 Waterfowl Breeding Population and Habitat Survey of Southern Saskatchewan was conducted 5-31 May and was consistent in design and coverage to previous years surveys. Wetland and upland habitat conditions were variable across Southern Saskatchewan...
The 2006 Waterfowl Breeding Population and Habitat Survey of Southern Saskatchewan was conducted 5-25 May and was consistent in design and coverage to previous surveys. Wetland and upland habitat conditions were variable across Southern Saskatchewan durin...
Mosquito-vectored pathogens are responsible for devastating human diseases and are (re)emerging in many urban environments. Effective mosquito control in urban landscapes relies on improved understanding of the complex interactions between the ecological and social factors that define where mosquito populations can grow. We compared the density of mosquito habitat and pupae production across economically varying neighborhoods in two temperate U.S. cities (Baltimore, MD and Washington, DC). Se...
Ladeau, Shannon L.; Leisnham, Paul T.; Dawn Biehler; Danielle Bodner
Mosquitoes are serious biting pests and obligate vectors of many vertebrate pathogens. Their immature larval and pupal life stages are a common feature in most tropical and many temperate water bodies and often form a significant proportion of the biomass. Control strategies rely primarily on the use of larvicides and environmental modification to reduce recruitment and adulticides during periods of disease transmission. Larvicides are usually chemical but can involve biological toxins, agents or organisms. The use of insect predators in mosquito control has been exploited in a limited fashion and there is much room for further investigation and implementation. Insects that are recognized as having predatorial capacity with regard to mosquito prey have been identified in the Orders Odonata, Coleoptera, Diptera (primarily aquatic predators), and Hemiptera (primarily surface predators). Although their capacity is affected by certain biological and physical factors, they could play a major role in mosquito control. Furthermore, better understanding for the mosquitoes-predators relationship(s) could probably lead to satisfactory reduction of mosquito-borne diseases by utilizing either these predators in control programs, for instance biological and/or integrated control, or their kairomones as mosquitoes' ovipoisting repellents. This review covers the predation of different insect species on mosquito larvae, predator-prey-habitat relationships, co-habitation developmental issues, survival and abundance, oviposition avoidance, predatorial capacity and integrated vector control. PMID:20237438
Shaalan, Essam Abdel-Salam; Canyon, Deon V
Full Text Available Relata-se o encontro de formas imaturas de Aedes albopictus em bromélias. Discute-se em que circunstâncias estas plantas poderiam ser epidemiologicamente consideradas como recipientes naturais ou artificiais. Destaca-se o poder de difusão deste vetor que deverá merecer atenção para que sejam elaborados modelos teóricos que se baseiem em maior número de informações.A breeding place of immature stages of Aedes albopictus in bromeliads is described. The epidemiological role of bromeliaceae as natural or artificial containers, is discussed. The ability of the mosquito to expand its habitat calls for attention especially as regards its adaptability as an invading species.
Oswaldo Paulo Forattini
The use of ecofriendly biodegradable controlled-release formulations of mosquito larvicides could reduce the frequency of application and losses due to degradation of the insecticide compared with conventional formulations. Among the 20 matrices developed by entrapping the organophosphorus mosquito larvicide, fenthion, in carboxymethylcellulose ionotropically cross-linked with aluminium ions which were studied for release profiles, two matrices, CRF3b and CRF5b, were found to be stable for 16 and 14 weeks under simulated field conditions. The average concentration of fenthion released per week ranged from 0.06 to 3.5 mg litre(-1) for CRF3b and 0.09 to 2.72 mg litre(-1) for CRF5b. Of these two formulations, CRF3b was the more stable, maintaining the concentration of the active ingredient at the level required to effect mosquito control. The cumulative release of fenthion per pellet was 80% from CRF3b and 72% from CRF5b. Based on the study with fenthion, two similar matrices for triflumuron, a benzoylphenylurea insect growth regulator, STAR3b and STAR5b were developed. These matrices were stable up to 16 weeks with the average concentration of triflumuron released per week ranging from 0.05 to 3.44 mg litre(-1) for STAR3b and 0.07 to 2.71 mg litre(-1) for STARSb. The cumulative release of triflumuron per pellet was 75% from STAR3b and 76% from STAR5b. From the results of this study under simulated conditions, it is estimated that the application of four pellets of either fenthion or triflumuron per square metre of the breeding surface may play a useful role in controlling Culex quinquefasciatus Say in larval habitats for about 4 months. PMID:15260300
Mathew, Nisha; Kalyanasundaram, Muthuswami
We compared habitat features of Golden-winged Warbler (Vermivora chrysoptera) territories in the presence and absence of the Blue-winged Warbler (V. cyanoptera) on reclaimed coal mines in southeastern Kentucky, USA. Our objective was to determine whether there are species specific differences in habitat that can be manipulated to encourage population persistence of the Golden-winged Warbler. When compared with Blue-winged Warblers, Golden-winged Warblers established territories at higher elev...
Patton, Laura L.; Maehr, David S.; Duchamp, Joseph E.; Songlin Fei; Gassett, Jonathan W.; Larkin, Jeffery L.
Control programs using conventional insecticides to target anthropogenic mosquito habitats are very expensive because these habitats are widespread, particularly in cities of most African countries. Additionally, there are serious environmental concerns regarding large-scale application of most conventional insecticides. Clearly there is a need for alternative methods that are more effective, less expensive, and environmentally friendly. One such method would be the application of preparations made from parts of the neem tree, Azadirachta indica A. Jussieu (Sapindales: Meliaceae). In this study, aqueous crude extracts and crude powder were prepared from different parts of neem, and the efficacies of the preparations on juvenile stages of Culex quinquefasciatus Say (Diptera: Culicidae) were evaluated in the laboratory. When larvae were exposed to a concentration of 0.1 g/mL extract for 24 hours, percent mean mortality (± SE) was 72.7 plusmn; 1.8 for the bark, 68.7 ± 1.6 for fruits and 60 ± 1.6 for leaves. These means were not significantly different (?(2) = 4.12; df = 2; p = 0.127). At a concentration of 0.01 g/mL, > 95% of the larvae died within 24 hours of exposure to powdered neem leaf, but it took 120 hours to reach the same level of larval mortality in aqueous leaf extract. The crude extract slowly inhibited the growth and development of mosquitoes while the crude powder acted more as a barrier; the mosquitoes probably died from suffocation. However, both types of preparations can be made and used by local people to control mosquito breeding in anthropogenic habitats, especially in urbanized areas. PMID:22233153
Kudom, Andreas A; Mensah, Ben A; Botchey, Mary A
Control programs using conventional insecticides to target anthropogenic mosquito habitats are very expensive because these habitats are widespread, particularly in cities of most African countries. Additionally, there are serious environmental concerns regarding large-scale application of most conventional insecticides. Clearly there is a need for alternative methods that are more effective, less expensive, and environmentally friendly. One such method would be the application of preparations made from parts of the neem tree, Azadirachta indica A. Jussieu (Sapindales: Meliaceae). In this study, aqueous crude extracts and crude powder were prepared from different parts of neem, and the efficacies of the preparations on juvenile stages of Culex quinquefasciatus Say (Diptera: Culicidae) were evaluated in the laboratory. When larvae were exposed to a concentration of 0.1 g/mL extract for 24 hours, percent mean mortality (± SE) was 72.7 plusmn; 1.8 for the bark, 68.7 ± 1.6 for fruits and 60 ± 1.6 for leaves. These means were not significantly different (?2 = 4.12; df = 2; p = 0.127). At a concentration of 0.01 g/mL, > 95% of the larvae died within 24 hours of exposure to powdered neem leaf, but it took 120 hours to reach the same level of larval mortality in aqueous leaf extract. The crude extract slowly inhibited the growth and development of mosquitoes while the crude powder acted more as a barrier; the mosquitoes probably died from suffocation. However, both types of preparations can be made and used by local people to control mosquito breeding in anthropogenic habitats, especially in urbanized areas.
Kudom, Andreas A.; Mensah, Ben A.; Botchey, Mary A.
Full Text Available Abstract Background The emergence of Anopheles populations capable of withstanding lethal doses of insecticides has weakened the efficacy of most insecticide based strategies of vector control and, has highlighted the need for further studies on the mechanisms of insecticide resistance and the various factors selecting resistant populations of mosquitoes. This research targeted the analysis of breeding sites and the oviposition behaviour of susceptible and resistant populations of Anopheles in localities of spilled petroleum products. The aim was to establish the possible contribution of oil spillage in the selection of pyrethroid resistance in malaria vectors. Methods Anopheles breeding sites were identified and the insecticide susceptibility of the Anopheles gambiae populations mapped in 15 localities of South Western Nigeria. The presence of oil particles as well as the turbidity, the dissolved oxygen and the pH of each identified breeding site was recorded. Data were cross-analysed to correlate the habitat types and the insecticide susceptibility status of emerging mosquitoes. The second phase of this study was basically a laboratory model to provide more information on the implication of the spillage of petroleum on the selection of pyrethroid resistance in An. gambiae. Results Moderate levels of resistance following exposure to permethrin-impregnated papers were recorded with the majority of An. gambiae samples collected in the South Western Nigeria. Data from this study established a link between the constituency of the breeding sites and the resistance status of the emerging Anopheles. Conclusion This study has revealed the segregational occupation of breeding habitats by pyrethroid resistant and susceptible strains of An. gambiae in south-western Nigeria. Compiled results from field and laboratory research point out clear relationships between oil spillage and pyrethroid resistance in malaria vectors. The identification of this factor of resistance could serve as strong information in the management of insecticide resistance in some West African settings.
The southern province of Guangdong has long been subject to endemic mosquito-borne diseases. In recent years, this region of China has experienced rapid, extensive economic development involving environmental change, making much of the scant knowledge of its mosquito fauna obsolete. This paper reviews previous mosquito surveys, some of which may be too old to be of relevance to present-day conditions, and presents the results of a recent survey of adult and immature mosquitoes. The main vectors of mosquito-borne diseases endemic to the area, such as dengue and Japanese encephalitis virus, develop in container habitats. A three-year survey was carried out, between 2004 and 2006, of 4131 breeding containers in residential areas and in open, sparsely populated areas, of which approximately 50% were positive for the presence of mosquitoes, and 10 156 larvae and pupae were collected and identified. Twelve species were found in both residential and sparsely populated areas: Aedes albopictus (Skuse) (Diptera: Culicidae), Ae. lineatopennis (Ludlow), Ae. vexans (Meigen), Tanakaius togoi (Theobald), Culex barraudi Edwards, Cx dispectus Bram, Cx malayi (Leicester), Cx pallidothorax Theobald, Cx quinquefasciatus Say, Cx sitiens Wiedemann, Lutzia fuscanus Wiedemann and Tripteroides bambusa (Yamada). Armigeres subalbatus (Coquillett) was found only in containers in villages, whereas Ae. macfarlanei Edwards, Cx mimeticus Noé, Cx sinensis Theobald, Cx vegans Wiedemann, Cx wilfredi Colless and Mansonia uniformis (Theobald) were found only in non- or sparsely populated areas. In residential areas, the rank order of most common species, as measured by the proportion of containers colonized, was Ae. albopictus > Cx quinquefasciatus > Lu. fuscanus, whereas in sparsely populated areas the rank order was Cx quinquefasciatus > Ae. albopictus > Lu. fuscanus. Light traps in non- or sparsely populated areas caught 5995 adult mosquitoes of 25 species, some of which are not container breeders. The most common species were: Anopheles sinensis Wiedemann, An. maculatus Theobald, An. minimus Theobald, Ta. togoi, Cx bitaeniorhynchus Giles, Cx malayi, Cx quinquefasciatus, Cx sinensis Theobald, Cx sitiens, Cx tritaeniorhynchus Giles and Lu. fuscanus. It is noteworthy that nine species caught had not been previously recorded in Guangdong Province, highlighting the deficient knowledge of the current composition and distribution of the mosquito fauna of this part of China. PMID:19120964
Jin, L Q; Li, D
Full Text Available We compared habitat features of Golden-winged Warbler (Vermivora chrysoptera territories in the presence and absence of the Blue-winged Warbler (V. cyanoptera on reclaimed coal mines in southeastern Kentucky, USA. Our objective was to determine whether there are species specific differences in habitat that can be manipulated to encourage population persistence of the Golden-winged Warbler. When compared with Blue-winged Warblers, Golden-winged Warblers established territories at higher elevations and with greater percentages of grass and canopy cover. Mean territory size (minimum convex polygon was 1.3 ha (se = 0.1 for Golden-winged Warbler in absence of Blue-winged Warbler, 1.7 ha (se = 0.3 for Golden-winged Warbler coexisting with Blue-winged Warbler, and 2.1 ha (se = 0.3 for Blue-winged Warbler. Territory overlap occurred within and between species (18 of n = 73 territories, 24.7%. All Golden-winged and Blue-winged Warblers established territories that included an edge between reclaimed mine land and mature forest, as opposed to establishing territories in open grassland/shrubland habitat. The mean distance territories extended from a forest edge was 28.0 m (se = 3.8 for Golden-winged Warbler in absence of Blue-winged Warbler, 44.7 m (se = 5.7 for Golden-winged Warbler coexisting with Blue-winged Warbler, and 33.1 m (se = 6.1 for Blue-winged Warbler. Neither territory size nor distances to forest edges differed significantly between Golden-winged Warbler in presence or absence of Blue-winged Warbler. According to Monte Carlo analyses, orchardgrass (Dactylis glomerata, green ash (Fraxinus pennsylvanica seedlings and saplings, and black locust (Robinia pseudoacacia saplings were indicative of sites with only Golden-winged Warblers. Sericea lespedeza, goldenrod (Solidago spp., clematis vine (Clematis spp., and blackberry (Rubus spp. were indicative of sites where both species occurred. Our findings complement recent genetic studies and add another factor for examining Golden-winged Warbler population decline. Further, information from our study will aid land managers in manipulating habitat for the Golden-winged Warbler.
David S. Maehr
Brazilian mosquito (Diptera: Culicidae) fauna: I. Anopheles species from Porto Velho, Rondônia state, western Amazon, Brazil / Fauna brasileira de mosquitos (Diptera: Culicidae): I. Espécies de Anopheles de Porto Velho, estado de Rondônia, oeste da Amazônia, Brasil
Full Text Available SciELO Brazil | Language: English Abstract in portuguese Este estudo contribui para o conhecimento de espécies de Anopheles, incluindo vetores de Plasmodium do oeste da Amazônia brasileira, em Porto Velho, no estado de Rondônia. Esta região vem passando por mudanças ambientais, como consequência de agricultura extensiva e projetos hidroelétricos que causa [...] m desmatamento, favorecendo o desenvolvimento de algumas espécies de mosquitos. Assim, a proposta deste estudo é registrar a presença de espécies de anofelinos na área, sendo conduzidas coletas de mosquitos em três locais, ao longo de uma linha de transmissão de energia elétrica. Cada uma das localidades foi amostrada três vezes, no período de 2010 a 2011. Os principais mosquitos adultos capturados em armadilhas de Shannon foram Anopheles darlingi, An. triannulatus, An. nuneztovari l.s., An.gilesi e An. costai. Assim como as formas larvárias Anopheles braziliensis, An. triannulatus, An. darlingi, An. deaneorum, An. marajoara, An. peryassui, An. nuneztovari l.s. e An. oswaldoi-konderi, coletadas em criadouros. Anopheles darlingi foi a espécie mais coletada na região. Em adição, discutiu-se sistemática de Culicidae, distribuição de fauna e aspectos da malária em ambientes modificados do oeste da Amazônia brasileira. Abstract in english This study contributes to knowledge of Anopheles species, including vectors of Plasmodium from the western Brazilian Amazon in Porto Velho, Rondônia State. The sampling area has undergone substantial environmental changes as a consequence of agricultural and hydroelectric projects, which have caused [...] intensive deforestation and favored habitats for some mosquito species. The purpose of this study was to diagnose the occurrence of anopheline species from collections in three locations along an electric-power transmission line. Each locality was sampled three times from 2010 to 2011. The principal adult mosquitoes captured in Shannon trap were Anopheles darlingi, An. triannulatus, An. nuneztovari l.s., An.gilesi and An. costai. In addition, larvae were collected in ground breeding sites for Anopheles braziliensis, An. triannulatus, An. darlingi, An. deaneorum, An. marajoara, An. peryassui, An. nuneztovari l.s. and An. oswaldoi-konderi. Anopheles darlingi was the most common mosquito in the region. We discuss Culicidae systematics, fauna distribution, and aspects of malaria in altered habitats of the western Amazon.
Morais, Sirlei Antunes; Urbinatti, Paulo Roberto; Sallum, Maria Anice Mureb; Kuniy, Adriana Akemi; Moresco, Gilberto Gilmar; Fernandes, Aristides; Nagaki, Sandra Sayuri; Natal, Delsio.
Brazilian mosquito (Diptera: Culicidae fauna: I. Anopheles species from Porto Velho, Rondônia state, western Amazon, Brazil Fauna brasileira de mosquitos (Diptera: Culicidae: I. Espécies de Anopheles de Porto Velho, estado de Rondônia, oeste da Amazônia, Brasil
Full Text Available This study contributes to knowledge of Anopheles species, including vectors of Plasmodium from the western Brazilian Amazon in Porto Velho, Rondônia State. The sampling area has undergone substantial environmental changes as a consequence of agricultural and hydroelectric projects, which have caused intensive deforestation and favored habitats for some mosquito species. The purpose of this study was to diagnose the occurrence of anopheline species from collections in three locations along an electric-power transmission line. Each locality was sampled three times from 2010 to 2011. The principal adult mosquitoes captured in Shannon trap were Anopheles darlingi, An. triannulatus, An. nuneztovari l.s., An.gilesi and An. costai. In addition, larvae were collected in ground breeding sites for Anopheles braziliensis, An. triannulatus, An. darlingi, An. deaneorum, An. marajoara, An. peryassui, An. nuneztovari l.s. and An. oswaldoi-konderi. Anopheles darlingi was the most common mosquito in the region. We discuss Culicidae systematics, fauna distribution, and aspects of malaria in altered habitats of the western Amazon.Este estudo contribui para o conhecimento de espécies de Anopheles, incluindo vetores de Plasmodium do oeste da Amazônia brasileira, em Porto Velho, no estado de Rondônia. Esta região vem passando por mudanças ambientais, como consequência de agricultura extensiva e projetos hidroelétricos que causam desmatamento, favorecendo o desenvolvimento de algumas espécies de mosquitos. Assim, a proposta deste estudo é registrar a presença de espécies de anofelinos na área, sendo conduzidas coletas de mosquitos em três locais, ao longo de uma linha de transmissão de energia elétrica. Cada uma das localidades foi amostrada três vezes, no período de 2010 a 2011. Os principais mosquitos adultos capturados em armadilhas de Shannon foram Anopheles darlingi, An. triannulatus, An. nuneztovari l.s., An.gilesi e An. costai. Assim como as formas larvárias Anopheles braziliensis, An. triannulatus, An. darlingi, An. deaneorum, An. marajoara, An. peryassui, An. nuneztovari l.s. e An. oswaldoi-konderi, coletadas em criadouros. Anopheles darlingi foi a espécie mais coletada na região. Em adição, discutiu-se sistemática de Culicidae, distribuição de fauna e aspectos da malária em ambientes modificados do oeste da Amazônia brasileira.
Sirlei Antunes Morais
Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Experimentos foram feitos no laboratório e no campo nos anos de 1980 a 1984, objetivando detectar as causas do repovoamento de criadouros de Biomphalaria glabrata após tratamento com niclosamida. Os bioensaios no laboratório mostraram que a suscetibilidade à niclosamida emulsionável de B. glabrata c [...] oletada mensalmente em um sistema de valas de irrigação, variou durante o ano. As concentrações letais CL90 foram 0,15 mgl-1 a 0,60 mgl-1, apresentando diferenças significantes estatisticamente (p Abstract in english Experiments were undertaken both in the laboratory and in the field between 1980-1984 to evaluate the causes of repopulation of breeding places of Biomphalaria glabrata following treatment with Niclosamide. Laboratory bioassays showed that the susceptibility to emulsifiable Niclosamide of B. glabrat [...] a collected monthly from an irrigation ditch system varied during the year. Lethal concentrations (LC90) ranged between 0.15 mg/l-1 and 0.60 mg/l-1. Statistically significant differences (alpha=0.01) were evident between the months of May/82 and January/83 and December/82 and January/83, and were related to snail nutrition. In the field two types of foci of B. glabrata were treated with 10 ppm of Niclosamide. The first one consisted of a reservoir of 12000 1 of water in which 14.5% of snails were infected with Schistosoma mansoni. One application of molluscicide followed by cleaning of the reservoir eliminated all the snails. The second one consisted of an irrigation system in which 5.6% of the snails were infected with S. mansoni. One application of molluscicide without cleaning the ditches reduced the density of snails by 98%. The causes of the survival of 2.0% of the snails in the ditches are discussed in relation to the substratum of the breeding places and the treatment technique.
Souza, Cecília Pereira de; Mendes, Nelymar Martineli.
This study aims at investigating the spawning migration of the endemic Labeobarbus species and C. gariepinus from Lake Tana, through Ribb River, to Welala and Shesher wetlands. The study was conducted during peak spawning months (July to October, 2010). Fish were collected through overnight gillnet settings. A total of 1725 specimens of the genus Labeobarbus (13 species) and 506 specimens of C. gariepinus were collected. Six species of Labeobarbus formed prespawning aggregation at Ribb River mouth. However, no Labeobarbus species was found to spawn in the two wetlands. More than 90% of the catch in Welala and Shesher wetlands was contributed by C. gariepinus. This implies that these wetlands are ideal spawning and nursery habitats for C. gariepinus but not for the endemic Labeobarbus species. Except L. intermedius, all the six Labeobarbus species (aggregated at Ribb River mouth) and C. gariepinus (spawning at Shesher and Welala wetlands) were temporally segregated. PMID:22654587
Anteneh, Wassie; Dejen, Eshete; Getahun, Abebe
This factsheet from the Environmental Protection Agency includes several summary documents on the problem of mosquito-borne diseases and the pesticides used to control mosquitoes. The resources cover issues from mosquito biology through the EPA's recent findings on the negative health impacts of Malathion.
Full Text Available Mosquito is a kind of important medical insects. Mosquito biological and morphological taxonomic research is the premise of effective control of mosquitoes. Specimen making of the mosquito egg, larvae, pupa and adult, genitalia is essential for taxonomic study. However, the technology for mosquito specimens making is yet to be improved and perfected. With many years of practice and improvement, this paper proposes the ideal and portable tools of specimen making, and the specimen making processing of the eggs, larvae, pupae, larval and pupal exuviae, adults, male and female genitalia, and also introduces the packaging and mailing method of mosquito pincushion specimens and slide specimens. These techniques have a lot of improvements on the basis of earlier protocols, and can provide with for the making, and transport of mosquito specimens.
Mosquito-borne infections cause some of the most debilitating human diseases, including yellow fever and malaria, yet we lack an understanding of how disease risk scales with human-driven habitat changes. We present an approach to study variation in mosquito distribution and concomitant viral infections on the landscape level. In a pilot study we analyzed mosquito distribution along a 10-km transect of a West African rainforest area, which included primary forest, secondary forest, plantation...
Junglen, S.; Kurth, A.; Kuehl, H.; Quan, P. L.; Ellerbrok, H.; Pauli, G.; Nitsche, A.; Nunn, Charles Lindsay; Rich, S. M.; Lipkin, W. I.; Briese, T.; Leendertz, F. H.
Mosquito-borne infections cause some of the most debilitating human diseases, including yellow fever and malaria, yet we lack an understanding of how disease risk scales with human-driven habitat changes. We present an approach to study variation in mosquito distribution and concomitant viral infections on the landscape level. In a pilot study we analyzed mosquito distribution along a 10-km transect of a West African rainforest area, which included primary forest, secondary forest, planta...
Junglen, Sandra; Kurth, Andreas; Kuehl, H.; Quan, Phenix-lan; Ellerbrok, Heinz; Pauli, Georg; Nitsche, Andreas; Nunn, Charles L.; Rich, S. M.; Briese, Thomas; Leendertz, Fabian
Abstract Background Although adult mosquito vectors of sylvatic arbovirus [yellow fever (YFV), dengue-2 (DENV-2) and chikungunya (CHIKV)] have been studied for the past 40 years in southeastern Senegal, data are still lacking on the ecology of larval mosquitoes in this area. In this study, we investigated the larval habitats of mosquitoes and characterized their seasonal and spatial dynamics in arbovirus foci. Methods We searched for wet microhabitats, classifie...
A field study was carried out in the large-scale rice irrigation scheme of the Office du Niger in Mali to investigate the relation between anopheline mosquito larval development and small-scale differences in irrigation practices, such as water level, irrigation application and irrigation frequency. The objective of the study was to find out if water management can be used as a tool for vector control to reduce the malaria transmission risk. Larvae of Anopheles gambiae s.s.,; the main malaria vector in the study area, developed mostly in the first 6 weeks after transplanting the rice. During rice development, a succession of anopheline species was observed. This was associated with a marked decrease in light intensity reaching the water surface as plant height increased. Minor differences in water management resulted in noticeable variations in larval densities and species composition. A. gambiae s.s. larvae were most abundant during the early growing stages and almost absent in a closed rice crop. Due to improper drainage after harvest, A. gambiae s.s. breeding was soon re-established in fields where small pools of water were retained. The results suggest that larval mosquito habitats in the Office du Niger can be significantly reduced by water management, simultaneous planting and harvesting and proper drainage of fallow fields. PMID:12505185
Klinkenberg, E; Takken, W; Huibers, F; Touré, Y T
Full Text Available A study was conducted during the summer of 2009 (from July to September to characterize mosquito communities among different habitats in five historically ditched tidal salt marshes and three adjacent wooded areas in the E.A. Vaughn Wetland Management Area on the Maryland Delmarva Peninsula, USA. Study marshes are characteristic of Atlantic coastal salt marshes that had undergone grid ditching from the 1930s to 1950s. In the autumn of 2008 (October and November ditches were plugged near their outlets in two (‘experimental’ marshes with the aim to restore their natural tidal hydrology. The three other marshes were not plugged. Marshes were sampled from July to September in 2009 by using standard dip count method. A total of 2,457 mosquito larvae representing six species were collected on 15.4% (86/557 of all sample occasions and 399 adults representing four mosquito species were collected from landing counts. Aedes sollicitans, Anopheles bradleyi and Culex salinarius were the most common species collected in larval habitats, and Ae. sollicitans was the most common adult collected. Wooded habitats had more total mosquitoes, were also more frequently occupied by mosquitoes and had higher densities of mosquitoes than marsh habitats. Almost all larvae collected from marshes were from one experimental and one control site. The majority of larvae at the control site were Ae. sollicitans in marsh pannes while Cx. salinarius, An. bradleyi, Ae. cantator, and Ae. sollicitans were collected in high numbers from ditches at the experimental site. We found a difference in the proportion of marsh pannes occupied by Ae. sollicitans but not total mosquitoes sampled 4–5 days after spring tide events than on other occasions. Salinity measures of 42 larval habitats showed lower median salinity in mosquito-occupied habitats (11.5 ppt than unoccupied habitats (20.1 ppt, and in habitats in wooded areas followed by ditches and pannes in marsh areas. The results of this study suggest that wooded areas adjacent to salt marshes may be a substantial source of biting adult mosquitoes usually associated with salt marsh habitats and that ditch plugging may alter the productivity of mosquitoes on some marshes. We recommend future studies consider mosquito productivity from habitats surrounding salt marshes, and if assessments of marsh alterations are a goal, compare multiple experimental and control areas before and after treatments to determine if alterations have a consistent impact on regional mosquito production.
Paul T. Leisnham
Full Text Available Dengue Hemorrhagic Fever (DHF prevention programs in Semarang, were focused through controlling mosquito breeding sites (PSN, but the implementation of PSN was not become a habit in every household. The objective of this study was to explore knowledge and experience of dengue mosquitoes among housewives in the endemic villages.The research was using qualitative methods. Subjects of the study were 17 housewives which selected by purposive sampling. The data collection was carried in Sendangmulyo village, Semarang, through observation, focus groups discussions, and indepth interviews. The techniques used to test data validity were triangulation and member checking method. Data were analyzed using content analysis approached. The results showed that housewives classifying mosquito based on time occurrence whether the presence of mosquito in environment was perceived naturally. Unoptimalized PSN behavior was based on the lack of housewives knowledge on larvae development stages. Mosquito was not considered as a threatening because night mosquito biting was directly more disturbing rather than day mosquitoes’. Health promotion program could increase dasa wisma cadres knowledge and skill, particularly on mosquito life cycle and the correct stages of PSN behavior. This study did not distinguish the demographic characteristics of informants. Further reserch could explore it or develop media based on local knowledge and experience.
Culicine mosquito were surveyed in El Menoufia Governorate (October to November 2008 and April to May 2009) in villages representing eight districts. Six species were reported: Culex (Culex) pipiens Linnaeus, Cx. (Cx) perexiguus Theobald, Cx. (Cx.) antennatus (Becker), Aedes (Ochlerotatus) caspius (Pallas), Aedes (Ochlerotatus) detritus (Haliday) and Culiseta (Allotheobaldia) longiareolata (Macquart). Cx. pipiens, the main filariasis vector was the commonest or predominating species (ca. 47% adults & 92% larvae, P < 0.01). For the common species, the following were investigated: 1- temperature and pH of the breeding habitats and their relation to the larval density and 2- relation of adult indoor density with indoor- and outdoor- temperature and RH. Besides, parasitologically, Wuchereria bancrofti cases (33/631 blood samples, 5.23%) were detected in three districts (range = 1.96-14.12% infection). The cases were associated with the abundance of Cx. pipiens adults (ca. 45- 62% of the collected adults). PMID:21634247
Abdel-Hamid, Yousrya M; Soliman, Mohamed I; Kenawy, Mohamed A
Ecologia de mosquitos (Diptera, Culicidae em criadouros naturais e artificiais de área rural do norte do Parana, Brasil: II. Coletas com isca humana Ecology of mosquitoes (Diptera, Culicidae in natural and artificial breeding sites of the rural area in north Paraná, Brazil: II. Capture of human bait
Full Text Available With then purpose of knowing the species of mosquitos that colonize an anthropogenic area in the North of Paraná, Brazil. 1496 specimens were captured by the humam bait method, accountig 23 species among them the following were predominam: Anopheles strodei Root, 1926; An. evansae Brethes, 1926; An. galvaoi Causey, Deane & Deane, 1943; An. albitarsis Lynch Arribalzaga, 1878; Coquillettidea juxtamansonia Chagas, 1907; Co. venezuelensis Theobaldi, 1912; Culex (Melanoconion sp. e Aedes fluviatilis (Lutz, 1904 and showed shong anthopophilia and a high degree of adaptation to humam environment. On the cantray, the species that showed lilth adaptation to such ambients or to the geoclimatic conditions of the region were: Anopheles triannulatus (Neiva & Pinto, 1922; An. parvus (Chagas, 1907; An. lutzii Cruzi, 1901, Culex amazonensis (Lutz, 1905; Cx. chidesteri; Psorophora confinnis (Linch Arribalzaga, 1891; Ps. discrucians (Walker, 1856; Ps. cingulata (Fabricius, 1805 e Aedes scapularis. Although Anopheles argyritarsis Robineau-Desvoidy, 1827; Culex coronator Dyar & Knab, 1906; Cx. mollis Dyar & Knab, 1906 and Cx. quinquefasciatus Say, 1823, were captured in little numbers, it is knowntht they an mosquito of human surroundings. These mosquitos showed a plak of feeding activity directly related to sunset bat did not have a bimodal behaviour. Anophelinae were in general more active in spring while Culex Linnaeus, 1758; Coquillettidia Dyar, 1905; Aedes Meigen, 1818; Mansonia Blanchard, 1901 e Psorophora Robineau-Desvoidy, 1827 were more active in summer.
Habitat preferences of the field sparrow (Spizella pusilla) are described in this report, which is one of a series of Habitat Suitability Index (HSI) models. A review and synthesis of the literature is followed by the development of a habitat model for the field sparrow throughout its breeding range in the United States. HSI models are designed to be used in conjunction with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.
Sousa, Patrick J.
Full Text Available "nAbstract "nBackground: Regarding to the significant of the possibility of the malaria epidemic and nuisance of mosquitoes during the active season, the fauna and some ecological activities of mosquitoes in related to tree holes were investigated from April to December 2009 in Neka county of Mazandaran Province, northern Iran. "nMethods: Larval collection was carried out from natural, artificial breeding places, and tree holes inside the forest in Neka County, Mazandaran Province in 2009. In addition, human bait net trap collection was conducted using suction tube several times during this investigation. "nResults: Four genera and five species were found in tree holes. Anopheles plumbeus, Culiseta annulata, Culex pipiens, and Ochlerotatus geniculatus were collected by larval collection whereas, Ochlerotatus pulcritarsis was found by adult collection. Overall Cx. pipiens 44.6%, Oc. geniculatus 32.6%, An. plumbeus 22.5%, and Cs. annulata 0.3% were collected by larval collection. During the bait net collection five specie were identified including: Oc. geniculatus 55.87%, Oc. echinus 1.33%, Oc. pulchritarsis 8.8 %, Cx. pipiens 33.8%, and An. plumbeus 0.2%. Cs. annulata larvae was detected for the first time with a low abundance in tree cavity. "nConclusion: Tree holes were found the main habitat for the species of Oc. geniculatus. The species of Cs. annulata was found in tree holes "n "nKeywords: Mosquito, fauna, tree holes, diversity, Iran
Full Text Available Background: There is very little information about the mosquito fauna of Qom Province, central Iran. By now only three species; Anopheles claviger, An. multicolor, and An. superpictus have been reported in the province. To study mosquito fauna and providing a primary checklist, an investigation was carried out on a collection of mosquitoes in this province.Methods: To study the mosquito (Diptera: Culicidae fauna, larval collections were carried out from different habitats on 19 occasions using the standard dipping technique during spring and summer 2008 and 2009.Results: In total, 371 mosquito larvae were collected and morphologically identified including 14 species representing four genera: Anopheles claviger, An. marteri, An. turkhudi, An. superpictus, Culex arbieeni, Cx. hortensis, Cx. mimeticus, Cx. modestus, Cx. pipiens, Cx. territans, Cx. theileri, Culiseta longiareolata, Cs. subochrea, and Ochlerotatus caspius s.l. All species except for An. claviger and An. superpictus were collected for the first time in the province. All larvae were found in natural habitats. The association occasions and percentages of the mosquito larvae in Qom Province were discussed.Conclusion: There are some potential or proven vectors of different human and domesticated animal pathogens in Qom Province. The ecology of these species and the unstudied areas of Qom Province need to be investigated extensively.
Full Text Available Background: There is very little information about the mosquito fauna of Qom Province, central Iran. By now only three species; Anopheles claviger, An. multicolor, and An. superpictus have been reported in the province. To study mosquito fauna and providing a primary checklist, an investigation was carried out on a collection of mosquitoes in this province.Methods: To study the mosquito (Diptera: Culicidae fauna, larval collections were carried out from different habitats on 19 occasions using the standard dipping technique during spring and summer 2008 and 2009. Results: In total, 371 mosquito larvae were collected and morphologically identified including 14 species representing four genera: Anopheles claviger, An. marteri, An. turkhudi, An. superpictus, Culex arbieeni, Cx. hortensis, Cx. mimeticus, Cx. modestus, Cx. pipiens, Cx. territans, Cx. theileri, Culiseta longiareolata, Cs. subochrea, and Ochlerotatus caspius s.l. All species except for An. claviger and An. superpictus were collected for the first time in the province. All larvae were found in natural habitats. The association occasions and percentages of the mosquito larvae in Qom Province were discussed.Conclusion: There are some potential or proven vectors of different human and domesticated animal pathogens in Qom Province. The ecology of these species and the unstudied areas of Qom Province need to be investigated extensively.
More focus is given to mosquito larval control due to the necessity to use several control techniques together in integrated vector management programmes. Botanical products are thought to be able to provide effective, sustainable and cheap mosquito larval control tools. However, bio-larvicides like Azadirachta indica (neem) could repel adult mosquitoes from laying their eggs in the treated larval habitats. In this study the response of Anopheles gambiae s.s. mosquitoes towards varying doses ...
Howard, A. F. V.; Adongo, E. A.; Vulule, J.; Githure, J.
Highlights: •Mosquito tolerance to temephos is induced by PAHs and UV exposure. •Toxicity of fluoranthene for mosquito Malpighian tubules cells is induced by UV. •Fluoranthene crystallizes in mosquito Malpighian tubules upon UV exposure. •Mixture of two PAHs is less toxic for mosquitoes than each PAHs separately. •Combination of abiotic parameters (PAHs and UV) affect mosquito physiology. -- Abstract: Mosquito breeding sites consist of water pools, which can either be large open areas or highly covered ponds with vegetation, thus with different light exposures combined with the presence in water of xenobiotics including polycyclic aromatic hydrocarbons (PAHs) generated by urban pollution. UV light and PAHs are abiotic factors known to both affect the mosquito insecticide resistance status. Nonetheless, their potential combined effects on the mosquito physiology have never been investigated. The present article aims at describing the effects of UV exposure alongside water contamination with two major PAH pollutants (fluoranthene and benzo[a]pyrene) on a laboratory population of the yellow fever mosquito Aedes aegypti. To evaluate the effects of PAH exposure and low energetic UV (UV-A) irradiation on mosquitoes, different parameters were measured including: (1) The PAH localization and its impact on cell mortality by fluorescent microscopy; (2) The detoxification capacities (cytochrome P450, glutathione-S-transferase, esterase); (3) The responses to oxidative stress (Reactive Oxygen Species–ROS) and (4) The tolerance of mosquito larvae to a bioinsecticide (Bacillus thuringiensis subsp. israelensis–Bti) and to five chemical insecticides (DDT, imidacloprid, permethrin, propoxur and temephos). Contrasting effects regarding mosquito cell mortality, detoxification and oxidative stress were observed as being dependent on the pollutant considered, despite the fact that the two PAHs belong to the same family. Moreover, UV is able to modify pollutant effects on mosquitoes, including tolerance to three insecticides (imidacloprid, propoxur and temephos), cell damage and response to oxidative stress. Taken together, our results suggest that UV and pollution, individually or in combination, are abiotic parameters that can affect the physiology and insecticide tolerance of mosquitoes; but the complexity of their direct effect and of their interaction will require further investigation to know in which condition they can affect the efficacy of insecticide-based vector control strategies in the field.
Tetreau, Guillaume, E-mail: firstname.lastname@example.org [Laboratoire d’Ecologie Alpine, LECA-UMR 5553, Université de Grenoble 1, BP 53, 38041 Grenoble cedex 09 (France); Department of Entomology, Cornell University, New York State Agricultural Experiment Station, Geneva, NY 14456 (United States); Chandor-Proust, Alexia; Faucon, Frédéric; Stalinski, Renaud; Akhouayri, Idir; Prud’homme, Sophie M.; Régent-Kloeckner, Myriam; Raveton, Muriel; Reynaud, Stéphane [Laboratoire d’Ecologie Alpine, LECA-UMR 5553, Université de Grenoble 1, BP 53, 38041 Grenoble cedex 09 (France)
Highlights: •Mosquito tolerance to temephos is induced by PAHs and UV exposure. •Toxicity of fluoranthene for mosquito Malpighian tubules cells is induced by UV. •Fluoranthene crystallizes in mosquito Malpighian tubules upon UV exposure. •Mixture of two PAHs is less toxic for mosquitoes than each PAHs separately. •Combination of abiotic parameters (PAHs and UV) affect mosquito physiology. -- Abstract: Mosquito breeding sites consist of water pools, which can either be large open areas or highly covered ponds with vegetation, thus with different light exposures combined with the presence in water of xenobiotics including polycyclic aromatic hydrocarbons (PAHs) generated by urban pollution. UV light and PAHs are abiotic factors known to both affect the mosquito insecticide resistance status. Nonetheless, their potential combined effects on the mosquito physiology have never been investigated. The present article aims at describing the effects of UV exposure alongside water contamination with two major PAH pollutants (fluoranthene and benzo[a]pyrene) on a laboratory population of the yellow fever mosquito Aedes aegypti. To evaluate the effects of PAH exposure and low energetic UV (UV-A) irradiation on mosquitoes, different parameters were measured including: (1) The PAH localization and its impact on cell mortality by fluorescent microscopy; (2) The detoxification capacities (cytochrome P450, glutathione-S-transferase, esterase); (3) The responses to oxidative stress (Reactive Oxygen Species–ROS) and (4) The tolerance of mosquito larvae to a bioinsecticide (Bacillus thuringiensis subsp. israelensis–Bti) and to five chemical insecticides (DDT, imidacloprid, permethrin, propoxur and temephos). Contrasting effects regarding mosquito cell mortality, detoxification and oxidative stress were observed as being dependent on the pollutant considered, despite the fact that the two PAHs belong to the same family. Moreover, UV is able to modify pollutant effects on mosquitoes, including tolerance to three insecticides (imidacloprid, propoxur and temephos), cell damage and response to oxidative stress. Taken together, our results suggest that UV and pollution, individually or in combination, are abiotic parameters that can affect the physiology and insecticide tolerance of mosquitoes; but the complexity of their direct effect and of their interaction will require further investigation to know in which condition they can affect the efficacy of insecticide-based vector control strategies in the field
The finding of Sabethes purpureus larvae and pupae in tree holes both in urban and forest environments in San Ramón de la Nueva Orán, Salta Province, Argentina, is reported, together with information on the larval habitat. Tree holes were sampled monthly from January to March or April of 2011, 2012, and 2013 along sidewalks, in public access areas, and in 3 sites within forested areas outside the city, selected along an urban gradient in Orán. Sabathes purpureus was most frequently found in low numbers and with other mosquito species. A higher proportion of tree holes was positive in the urban compared to the forest environment, although there were no significant differences in abundances or densities per hole. To our best knowledge, this paper reports the species for the first time breeding in an urban environment, and extends its geographical distribution from the Atlantic and Paranaense forests to the Southern Andean Yungas in northwestern Argentina. PMID:24772679
Mangudo, Carolina; Aparicio, Juan P
Amphibians such as frogs are at risk, especially those that have to travel from their homes in forest habitats to aquatic areas to breed and back; and with this added risk, the diversity, or variety, of species declines, according to a new report. Traveling to the water to breed, then returning to the forest is called habitat split, and researchers say that it is usually caused by human activity.
American Association for the Advancement of Science (AAAS;)
Full Text Available Background & objectives: This study aims at studying mosquito-borne diseases as the major publichealth threat in Iran. Sanandaj outskirts are considered suitable habitats for mosquito larvae. Inview of scanty reports on mosquito-borne disease implementation in this area, a study was undertakento determine the mosquito fauna and frequency of mosquito larvae at Sanandaj City.Methods: In order to study the mosquito (Diptera: Culicidae fauna, the samples were collectedfrom May to July 2009 using dipping and night catch methods in Sanandaj district, Kurdistanprovince, western Iran.Results: Three genera and 11 species of the Culicinae subfamily were identified—Aedes vexansMeigen, Ochlerotatus caspius s.l. Pallas (indicating new occurrence records for the province,Culex hortensis Ficalbi, Cx. pipiens Linnaeus, Cx. mimeticus Noe, Cx. theileri Theobald, Culisetalongiareolata Macquart, and Cs. subochrea Edwards.Interpretation & conclusion: Present study revealed that Ae. vexans and Ochlerotatus caspius s.lcaught had not been previously recorded in Kurdistan province, highlighting the deficient knowledgeof the fauna and distribution of Culicinae mosquitoes of this part of Iran
S.H. Moosa Kazemi
Full Text Available Background & objectives : Mosquito fauna diversity in mountainous areas of Garhwal region wasstudied during November 2000 to October 2002 to correlate the altitudinal vegetation and distributionof mosquitoes.Methods : Adult mosquitoes and mosquito immatures were collected using WHO methods and identifiedusing standard keys and catalogues. Altitude of mosquito habitat was measured using portablealtimeter and also by GPS.Results : Altogether 34 species in five genera — Aedes, Anopheles, Armigeres, Culex and Uranotaeniawere encountered in the present study in the altitude range of 300 to 2000 m. Majority of themosquitoes were found in between 300 to 900 m altitude except Culex vagus and Anopheles maculatus,which were found throughout the range.Interpretation & conclusion : The mosquitoes were categorised into six groups based on their altitudinaldistribution. The areas at lowest elevation were having the greatest number of species but notthe corresponding greater number of specimens in the present study.
N. Pemola Devi , R.K. Jauhari
Mosquito breeding sites consist of water pools, which can either be large open areas or highly covered ponds with vegetation, thus with different light exposures combined with the presence in water of xenobiotics including polycyclic aromatic hydrocarbons (PAHs) generated by urban pollution. UV light and PAHs are abiotic factors known to both affect the mosquito insecticide resistance status. Nonetheless, their potential combined effects on the mosquito physiology have never been investigated. The present article aims at describing the effects of UV exposure alongside water contamination with two major PAH pollutants (fluoranthene and benzo[a]pyrene) on a laboratory population of the yellow fever mosquito Aedes aegypti. To evaluate the effects of PAH exposure and low energetic UV (UV-A) irradiation on mosquitoes, different parameters were measured including: (1) The PAH localization and its impact on cell mortality by fluorescent microscopy; (2) The detoxification capacities (cytochrome P450, glutathione-S-transferase, esterase); (3) The responses to oxidative stress (Reactive Oxygen Species-ROS) and (4) The tolerance of mosquito larvae to a bioinsecticide (Bacillus thuringiensis subsp. israelensis-Bti) and to five chemical insecticides (DDT, imidacloprid, permethrin, propoxur and temephos). Contrasting effects regarding mosquito cell mortality, detoxification and oxidative stress were observed as being dependent on the pollutant considered, despite the fact that the two PAHs belong to the same family. Moreover, UV is able to modify pollutant effects on mosquitoes, including tolerance to three insecticides (imidacloprid, propoxur and temephos), cell damage and response to oxidative stress. Taken together, our results suggest that UV and pollution, individually or in combination, are abiotic parameters that can affect the physiology and insecticide tolerance of mosquitoes; but the complexity of their direct effect and of their interaction will require further investigation to know in which condition they can affect the efficacy of insecticide-based vector control strategies in the field. PMID:24275062
Tetreau, Guillaume; Chandor-Proust, Alexia; Faucon, Frédéric; Stalinski, Renaud; Akhouayri, Idir; Prud'homme, Sophie M; Régent-Kloeckner, Myriam; Raveton, Muriel; Reynaud, Stéphane
This book, for grades 2-6, is designed to provide students with a highly motivating and unique opportunity to investigate an aquatic habitat. Students set up, observe, study, and reflect upon their own "desktop ponds." Accessible plants and small animals used in these activities include Elodea, Tubifex worms, snails, mosquito larvae, and fish.…
Barrett, Katharine; Willard, Carolyn
Full Text Available Background: Mosquito borne diseases is a growing urban problem because of unplanned urbanization, industrialization and excessive population growth coupled with rural to urban migration. For developing a suitable and effective health education strategy, it is inevitable to understand the level of knowledge of the community, their attitude and practices regarding mosquito borne diseases. Materials and Methods: The present study was carried out in an urban field practice area of Urban Health Centre in Rajkot city. Total 500 houses were selected for study by systematic random sampling. Data was collected using a semi-structured questionnaire during transmission season of vector borne diseases. The results were analyzed using the SPSS 17 software. Results: 90% respondents agreed that mosquitoes are a problem. 30.4% didn?t know breeding sites of mosquitoes. Only 11.6% of people associated clean water collections with mosquito breeding. Regarding diseases transmitted by mosquito, 62% answered malaria, 37.4% were not aware and 8.8% people mentioned about Filariasis, Dengue or Japanese encephalitis. 4.7% granted mosquito control as responsibility of community. 61.4 % were using repellents for prevention against mosquito bites and 39% not taking any preventive measure. 67.8% consulted private practitioner for treatment. Conclusion: Intensified efforts towards creating public awareness and mobilizing the community regarding the preventive measures they can take are needed. [National J of Med Res 2011; 1(2.000: 45-47
Amul B. Patel
The impact of emergent macrophyte species and crepuscular sprinkler disturbance on mosquito abundance over a 2-year period was measured in wetland mesocosms. Mosquito oviposition and abundance of immature mosquitoes and aquatic invertebrates were monitored in monotypic plots of small-stature (height of mature stands 2 m) California bulrush (Schoenoplectus californicus) without or with daily sprinkler showers to deter mosquito egg laying. Relative to wetlands without operational sprinklers, oviposition by culicine mosquitoes was reduced by > 99% and immature mosquito abundance was reduced by > 90% by crepuscular sprinkler applications. Mosquito abundance or distribution in wetlands did not differ between the two bulrush species subjected to the sprinkler treatment. Alkali bulrush wetlands without daily sprinkler treatments contained more egg rafts but significantly fewer mosquito larvae than did California bulrush wetlands. Predaceous damselfly naiads were 3-5 times more abundant in alkali bulrush than in California bulrush. Stem density, rate of spread, and autumnal mortality of alkali bulrush were higher than for California bulrush. Replacement of large emergent macrophytes by smaller species may enhance the efficacy of integrated mosquito management programs to reduce mosquito-transmitted disease cycles associated with multipurpose constructed wetlands used worldwide for water reclamation and habitat restoration. PMID:24581369
Popko, David A; Walton, William E
Predicting species’ responses to the combined effects of habitat and climate changes has become a major challenge in ecology and conservation biology. However, the effects of climatic and habitat gradients on species distributions have generally been considered separately. Here, we explore the relationships between the habitat and thermal dimensions of the ecological niche in European common birds. Using data from the French Breeding Bird Survey, a large-scale bird monitoring program, w...
Barnagaud, J. Y.; Devictor, V.; Jiguet, F.; Barbet Massin, M.; Le Viol, I.; Archaux, F.
Predicting species’ responses to the combined effects of habitat and climate changes has become a major challenge in ecology and conservation biology. However, the effects of climatic and habitat gradients on species distributions have generally been considered separately. Here, we explore the relationships between the habitat and thermal dimensions of the ecological niche in European common birds. Using data from the French Breeding Bird Survey, a large-scale bird monitoring program, w...
Barnagaud, J. Y.; Devictor, V.; Jiguet, F.; Barbet Massin, M.; Le Viol, I.; Archaux, F.
The methods used to determine habitat classifications are important to planning and management. Therefore, the use of wildlife communities to improve habitat classification is crucial in Landscape Ecology. The importance of vegetation in the habitat use characteristics of breeding bird communities occurring in Évora (Portugal) was studied.
Quinta-nova, L. C.
Full Text Available Mosquito-vectored pathogens are responsible for devastating human diseases and are (reemerging in many urban environments. Effective mosquito control in urban landscapes relies on improved understanding of the complex interactions between the ecological and social factors that define where mosquito populations can grow. We compared the density of mosquito habitat and pupae production across economically varying neighborhoods in two temperate U.S. cities (Baltimore, MD and Washington, DC. Seven species of mosquito larvae were recorded. The invasive Aedes albopictus was the only species found in all neighborhoods. Culex pipiens, a primary vector of West Nile virus (WNV, was most abundant in Baltimore, which also had more tire habitats. Both Culex and Aedes pupae were more likely to be sampled in neighborhoods categorized as being below median income level in each city and Aedes pupae density was also greater in container habitats found in these lower income neighborhoods. We infer that lower income residents may experience greater exposure to potential disease vectors and Baltimore residents specifically, were at greater risk of exposure to the predominant WNV vector. However, we also found that resident-reported mosquito nuisance was not correlated with our measured risk index, indicating a potentially important mismatch between motivation needed to engage participation in control efforts and the relative importance of control among neighborhoods.
Newly established ponds, which are highly dynamic systems with changing levels of biological interactions among species, are common larval mosquito habitats. We investigated the impact of crustacean abundance and taxa diversity on mosquito oviposition and larval development. The effects of the biological larvicide Bacillus thuringiensis israelensis (Bti) on mosquito larvae were monitored according to fluctuations in crustacean communities. Populations of the mosquito Culex pipiens colonized artificial ponds that contained crustacean communities at different time points of colonization by crustaceans: 1) 'no colonization' (no crustaceans), 2) 'simultaneous colonization' by crustaceans and mosquitoes, and 3) 'head-start colonization' by crustaceans (preceding colonization by mosquitoes). All types of ponds were treated with three concentrations of Bti (10, 100, or 1,000 µg/liter). Colonization of all ponds by Cx. pipiens (in terms of oviposition, larval abundance, and larval development) decreased significantly with increasing diversity of crustacean taxa. The total abundance of crustaceans had a minor effect on colonization by Cx. pipiens. The presence of crustaceans increased the sensitivity of Cx. pipiens larvae to Bti treatment by a factor of 10 and delayed the time of recolonization. This effect of Bti was relevant in the short term. In the long term, the presence of Cx. pipiens was determined by crustacean biodiversity. PMID:24581370
Kroeger, Iris; Duquesne, Sabine; Liess, Matthias
Insect vector-borne diseases continue to present a major challenge to human health. Understanding the factors that regulate the size of mosquito populations is considered fundamental to the ability to predict disease transmission rates and for vector population control. The mosquito, Anopheles pseudopunctipennis, a vector of Plasmodium spp., breeds in riverside pools containing filamentous algae in Mesoamerica. Breeding pools along 3 km sections of the River Coatan, Chiapas, Mexico were subje...
Bond, J. Guillermo; Rojas, Julio C.; Arredondo-jime?nez, Juan I.; Quiroz-marti?nez, Humberto; Valle, Javier; Williams, Trevor
Bacillus thuringiensis subsp. israelensis is a bacterium producing crystals containing Cry and Cyt proteins, which are toxic for mosquito larvae. Nothing is known about the interaction between crystal toxins and decaying leaf litter, which is a major component of several mosquito breeding sites and represents an important food source. In the present work, we investigated the behavior of B. thuringiensis subsp. israelensis toxic crystals sprayed on leaf litter. In the presence of leaf litter, ...
Recently, designer mutts like the Labradoodle -- a cross between a Labarador retriever and a poodle -- have become popular. A listener wanted to know if some kinds of dogs are just too different to make puppies. This Science Update explores the cross breeding of species.
Full Text Available Infrastructure degradation in many post-industrial cities has increased the availability of potential mosquito habitats, including container habitats that support infestations of invasive disease-vectors. This study is unique in examining both immature and adult mosquito abundance across the fine-scale variability in socio-economic condition that occurs block-to-block in many cities. We hypothesized that abundant garbage associated with infrastructure degradation would support greater mosquito production but instead, found more mosquito larvae and host-seeking adults (86% in parcels across the higher socio-economic, low-decay block. Aedes albopictus and Culex pipiens were 5.61 (p < 0.001 and 4.60 (p = 0.001 times more abundant, respectively. Most discarded (garbage containers were dry during peak mosquito production, which occurred during the 5th hottest July on record. Containers associated with human residence were more likely to hold water and contain immature mosquitoes. We propose that mosquito production switches from rain-fed unmanaged containers early in the season to container habitats that are purposefully shaded or watered by mid-season. This study suggests that residents living in higher socioeconomic areas with low urban decay may be at greater risk of mosquito-borne disease during peak mosquito production when local container habitats are effectively decoupled from environmental constraints.
Infrastructure degradation in many post-industrial cities has increased the availability of potential mosquito habitats, including container habitats that support infestations of invasive disease-vectors. This study is unique in examining both immature and adult mosquito abundance across the fine-scale variability in socio-economic condition that occurs block-to-block in many cities. We hypothesized that abundant garbage associated with infrastructure degradation would support greater mosquito production but instead, found more mosquito larvae and host-seeking adults (86%) in parcels across the higher socio-economic, low-decay block. Aedes albopictus and Culex pipiens were 5.61 (p < 0.001) and 4.60 (p = 0.001) times more abundant, respectively. Most discarded (garbage) containers were dry during peak mosquito production, which occurred during the 5th hottest July on record. Containers associated with human residence were more likely to hold water and contain immature mosquitoes. We propose that mosquito production switches from rain-fed unmanaged containers early in the season to container habitats that are purposefully shaded or watered by mid-season. This study suggests that residents living in higher socioeconomic areas with low urban decay may be at greater risk of mosquito-borne disease during peak mosquito production when local container habitats are effectively decoupled from environmental constraints.
Becker, Brian; Leisnham, Paul T.; LaDeau, Shannon L.
...are not limited to: (1) Space for individual and population...and 3. Dispersal habitat connecting occupied Sonoma California...breeding and for providing space, food, and cover necessary...survive. Dispersal Habitat Connecting Occupied Sonoma...
The search for novel insect repellents has been driven by health concerns over established synthetic compounds such as diethyl-m-toluamide (DEET). Given the diversity of compounds known from frog skin and records of mosquito bite and ectoparasite infestation, the presence of mosquito repellents in frogs seemed plausible. We investigated frog skin secretions to confirm the existence of mosquito repellent properties. Litoria caerulea secretions were assessed for mosquito repellency by topical a...
Williams, C. R.; Smith, B. P. C.; Best, S. M.; Tyler, M. J.
Mosquitoes are vectors of major human diseases, such as malaria, dengue or yellow fever. Because no efficient treatments or vaccines are available for most of these diseases, control measures rely mainly on reducing mosquito populations by the use of insecticides. Numerous biotic and abiotic factors are known to modulate the efficacy of insecticides used in mosquito control. Mosquito breeding sites vary from opened to high vegetation covered areas leading to a large ultraviolet gradient exposure. This ecological feature may affect the general physiology of the insect, including the resistance status against insecticides. In the context of their contrasted breeding sites, we assessed the impact of low-energetic ultraviolet exposure on mosquito sensitivity to biological and chemical insecticides. We show that several mosquito detoxification enzyme activities (cytochrome P450, glutathione S-transferases, esterases) were increased upon low-energy UV-A exposure. Additionally, five specific genes encoding detoxification enzymes (CYP6BB2, CYP6Z7, CYP6Z8, GSTD4, and GSTE2) previously shown to be involved in resistance to chemical insecticides were found over-transcribed in UV-A exposed mosquitoes, revealed by RT-qPCR experiments. More importantly, toxicological bioassays revealed that UV-exposed mosquitoes were more tolerant to four main chemical insecticide classes (DDT, imidacloprid, permethrin, temephos), whereas the bioinsecticide Bacillus thuringiensis subsp. israelensis (Bti) appeared more toxic. The present article provides the first experimental evidence of the capacity of low-energy UV-A to increase mosquito tolerance to major chemical insecticides. This is also the first time that a metabolic resistance to chemical insecticides is linked to a higher susceptibility to a bioinsecticide. These results support the use of Bti as an efficient alternative to chemical insecticides when a metabolic resistance to chemicals has been developed by mosquitoes. PMID:23911355
Tetreau, Guillaume; Chandor-Proust, Alexia; Faucon, Frédéric; Stalinski, Renaud; Akhouayri, Idir; Prud'homme, Sophie M; Raveton, Muriel; Reynaud, Stéphane
Abstract Background Malaria is a serious health issue in Indonesia. Mosquito control is one aspect of an integrated malaria management programme. To focus resources on priority areas, information is needed about the vectors and their habitats. This research aimed to identify the relationship between anopheline mosquitoes and topography in West Timor and Java. Methods Study areas were selected in three topographic types in West Timor and Java. These were: coastal...
Ndoen Ermi; Wild Clyde; Dale Pat; Sipe Neil; Dale Mike
Full Text Available Abstract Background Anopheles arabiensis (Diptera: Culicidae is a potential malaria vector commonly present at low altitudes in remote areas in Reunion Island. Little attention has been paid to the environmental conditions driving larval development and abundance patterns in potential habitats. Two field surveys were designed to determine whether factors that discriminate between aquatic habitats with and without An. arabiensis larvae also drive larval abundance, comparatively in man-made and naturally occurring habitats. Methods In an initial preliminary survey, a representative sample of aquatic habitats that would be amenable to an intensive long-term study were selected and divided into positive and negative sites based on the presence or absence of Anopheles arabiensis larvae. Subsequently, a second survey was prompted to gain a better understanding of biotic and abiotic drivers of larval abundance, comparatively in man-made and naturally occurring habitats in the two studied locations. In both surveys, weekly sampling was performed to record mosquito species composition and larval density within individual habitats, as well as in situ biological characteristics and physico-chemical properties. Results Whilst virtually any stagnant water body could be a potential breeding ground for An. arabiensis, habitats occupied by their immatures had different structural and biological characteristics when compared to those where larvae were absent. Larval occurrence seemed to be influenced by flow velocity, macrofauna diversity and predation pressure. Interestingly, the relative abundance of larvae in man-made habitats (average: 0.55 larvae per dip, 95%CI [0.3–0.7] was significantly lower than that recorded in naturally occurring ones (0.74, 95%CI [0.5–0.8]. Such differences may be accounted for in part by varying pressures that could be linked to a specific habitat. Conclusions If the larval ecology of An. arabiensis is in general very complex and factors affecting breeding site productivity sometimes not easy to highlight, our results, however, highlight lower populations of An. arabiensis immatures compared to those reported in comparable studies conducted in the African continent. Overall, this low larval abundance, resulting from both abiotic and biotic factors, suggests that vector control measures targeting larval habitats are likely to be successful in Reunion, but these could be better implemented by taking environmental variability into account.
Full Text Available Photo catalytic mosquito trap is made of TiO2-Activated Carbon (AC with a certain composition of AC. Research concerns on the heat spectrum which is produced by combination process of existing CO2 and humid air. The purpose of performance testing is to observe capability of this device in trapping mosquitoes related to the air temperature profile for heat spectrum is play important role for attracting mosquitoes. Result shows photo catalytic mosquito trap is more effective than devices which only consist of UV light or stream of CO2 and the humid air. A number of mosquitoes trapped by the photo catalyst coated panel configuration and UV lamps were lit proved far more effective because the heat production from recombination process. A little difference in temperature can be detected by mosquito. Keywords: Photo Catalytic, Mosquito, Recombination.
How do we study what we cannot see or touch? Students learn about technologies used for underwater mapping, such as benthic habitat images produced by GIS. They participate in a class discussion on why habitat mapping is useful and how current technology works to make bathymetry mapping possible. Through inquiry-based questions, students brainstorm about the importance of bathymetry mapping to help us explore and map the seafloor, marine habitats and the water column. They examine collected data and draw conclusions. Students learn how remote sensing and underwater vehicles designed by engineers give scientists more data to be able to better map marine habitats.
Engineering K-Phd Program
Despite numerous ecological studies with mosquitoes, it remains unclear what environmental factors are the most important determinants of structure, species richness, and abundance of mosquito assemblages. In the current study, we investigated relations between these characteristics of mosquito larvae assemblages and environmental factors in a large set of different habitats. Particular objectives were (1) to rank the factors regarding their explanatory power, and (2) to quantify the contribution of major sets of factors such as habitat spatial/hydrological (H), water physico-chemical (W), and aquatic vegetation characteristics (V). Variance partitioning and forward selection based on ordinations and multiple regressions were applied to the data set on 79 water-bodies in southwestern Siberia covering a wide gradient of environmental characteristics and diverse mosquito assemblages. The results showed that richness and abundance inter-correlated poorly (r2 = 0.21), and assemblage structure, richness, and abundance depended on different sets of predictors. Explanatory importance of the three sets of environmental factors differed among the three assemblage variables: H, W, and V had equal importance for assemblage structure, while richness and abundance depended on H and V more than on W. The study showed that contradiction between the aims of conservation (support biodiversity) and mosquito control (reduce mosquito abundance) can be avoided, as relevant environmental factors can be used to define habitats with high richness and low abundance (i.e., high conservation value and low nuisance and disease transmission risk) for conservation activities, and conversely for control measures. PMID:20380292
Beketov, Mikhail A; Yurchenko, Yury A; Belevich, Olga E; Liess, Matthias
The spatial heterogeneity of larval teneral reserves and their influence on wing attribute indices of adult vectorial fitness of Culex pipiens pipiens mosquitoes in North central Nigeria were elucidated in this study. Late 4th instar larvae of the mosquito were collected from four different populations in the area and analysed for nutritional reserves following standard procedures. Also, emerging adults mosquitoes, from same habitats as larval collections, had their wings measured for ...
Ukubuiwe, A. C.; Olayemi, I. K.; Omalu, I. C. J.; Jibrin, A.; Oyibo-usman, K.
Organisms are attacked by different natural enemies present in their habitat. While enemies such as parasitoids and predators will kill their hosts/preys when they successfully attack them, enemies such as micropredators will not entirely consume their prey. However, they can still have important consequences on the performance and ecology of the prey, such as reduced growth, increased emigration, disease transmission. In this paper, we investigated the impact of a terrestrial micropredator, the yellow fever mosquito Aedes aegypti, on its unusual invertebrate host, the Egyptian cotton leaf worm, Spodoptera littoralis. Larvae developing in presence of mosquitoes showed a slower development and reached a smaller pupal weight when compared to a control without mosquitoes, apparently because of a reduced feeding time for larvae. In addition, larvae tended to leave the plant in presence of mosquitoes. These results suggest that mosquitoes act as micropredators and affects lepidopteran larvae behaviour and development. Ecological impacts such as higher risks of food depletion and longer exposure to natural enemies are likely to be costly consequences. The importance of this phenomenon in nature – the possible function as last resort when vertebrates are unavailable – and the evolutionary aspects are discussed.
Martel, Veronique; Schlyter, Fredrik; Ignell, Rickard; Hansson, Bill S.; Anderson, Peter
Full Text Available Mosquito borne diseases are major public health problems in India. Gujarat is endemic for malaria and other mosquito borne diseases. Anopheles, Aedes and Culex are commonly seen in Gujarat. Therefore the efforts have been consistently made to educate the citizens of State on danger of mosquito bites. The present study was conducted to assess the awareness and practices of mosquito bite prevention methods among households of Central Gujarat district Vadodara. Total 311 families have participated in the study from UHTC area of the Medical college. Door to door visit was conducted to visit the all households. The study was conducted in the month of June 2009, which is observed as Anti-Malaria month in Gujarat. The pilot pre-tested structure questionnaire was used to collect the data. Study respondents were 57% male and 43% female. Almost 99% had knowledge about breeding places of mosquito, but poor knowledge about biting time (20%. 71% of participants knew that mosquito bite causes malaria. 39% 0f households were using mosquito net as protection against the bite, but only 10% were using insecticide treated bed net. There is need of increasing use of insecticide treated bed nets and continuous updating of knowledge about various aspects of mosquito bite.
Aedes (Stegomyia) spp. mosquitoes breeding in containers in and around human houses were surveyed in Halmahela villages, the North Moluccas, Indonesia. Adults reared from larvae found in containers and those reared from eggs collected by ovitraps revealed the dominance of Aedes scutellaris (Walker) in residential areas. Breeding of Aedes aegypti (L.) and Aedes albopictus (Skuse) was confirmed in a few coastal villages with high human densities. PMID:8906924
Mogi, M; Miyagi, I; Toma, T; Hasan, M; Abadi, K; Syafruddin
Full Text Available The type of bacteria present on two insects (cockroach and mosquito were investigated. These microorganisms were screened for microbial control of mosquito employing their degradative ability at various microbial cell loads. The degradation of the mosquito was observed spectrophotometrically for an incubation period of 5 to 7 days. Six bacterial species (Escherichia coli, Pseudomonas aeruginosa, Bacillus cereus, Serratia marcescens, Staphylococcus aureus and Aerobacter aerogenes were isolated from cockroach. Mosquito borne E. coli, P. aeruginosa, B. cereus and Staph. aureus. All the bacteria digested the mosquito with activity ranging from 0.02 to 1.27. Microorganisms associated with cockroach showed higher degradation activity (0.02-1.27 during the incubation than those obtained from mosquito (0.02-1.00.
Rift Valley Fever (RVF) is a mosquito-borne virus that affects livestock and humans in Africa. Landsat TM data are shown to be effective in identifying dambos, intermittently flooded areas that are potential mosquite breeding sites, in an area north of Nairobi, Kenya. Positive results were obtained from a limited test of flood detection in dambos with airborne high resolution L, C, and X band multipolarization SAR imagery. L and C bands were effective in detecting flooded dambos, but LHH was by far the best channel for discrimination between flooded and nonflooded sites in both sedge and short-grass environments. This study demonstrates the feasibility of a combined passive and active remote sensing program for monitoring the location and condition of RVF vector habitats, thus making future control of the disease more promising.
Pope, K. O.; Sheffner, E. J.; Linthicum, K. J.; Bailey, C. L.; Logan, T. M.; Kasischke, E. S.; Birney, K.; Njogu, A. R.; Roberts, C. R.
Full Text Available Background & objectives: Changes in weather patterns especially rainfall affects the distribution and densities of mosquitoes. The objective of this study was to describe mosquito aquatic habitats, to determine larval abundance, species composition, and habitat types found in Kasayani village of Kibwezi division.Methods: A cross-sectional survey of mosquito larval habitats was conducted in Kasayani village in Kibwezi division to determine species composition, larval abundance, and habitat types found in this village. This survey was conducted during the rainy season in November and December 2006 and during the dry season in February and March 2007. Larvae were collected using the standard dipping technique and a total of 24 habitats were sampled. The primary habitats identified were water reservoir tanks, puddles, temporary pools, and tyre tracks. Results: A total of 2660 mosquito larvae were collected of which 2140 (80.45% were culicines, 503 (18.91% were Anopheles and 17 (0.64% were pupae. For culicines, 1787 (83.5% were categorized as early instars and 353 (16.5% were as late instars while in the Anopheles, 425 (84.49% were classified as early instars and 78 (15.51% were late instars. Morphological identification of the III and IV instar larvae by use of microscopy yielded 16.24% (n = 70 Anopheles gambiae complex, 1.16% (n = 5 An. funestus, 0.70% (n = 3 An. coustani, 42.46% (n = 183 Culex quinquefasciatus, 6.26% (n = 27 Cx. duttoni, and 33.18% (n = 143 Ae. aegypti. Puddles, tyre tracks and pools had highly turbid water while water reservoir tanks had clear water. Anopheles gambiae and Cx. quinquefasciatus were found in all habitat categories while Ae. aegypti were found only in water storage tanks. Interpretation & conclusion: The mosquito larval densities indicate that the inhabitants of this village are at risk of mosquito-borne diseases including malaria, which is one of the greatest causes of morbidity and mortality in this area. Furthermore, mosquito control measures targeting both the mosquito immatures and adults should be enhanced especially during the rainy season to ensure maximum protection of the inhabitants.
Joseph M. Mwangangi
Access to the article is free, however registration and sign-in are required. Forty years ago, as the first drug- and insecticide-based global malaria eradication plan was being abandoned, the concept was raised of using evolutionary genetics to fight vector-borne diseases like malaria, dengue, and river blindness (1).The idea was to exploit selfish genetic elements, entities that can spread through host populations by distorting normal Mendelian inheritance, thereby enhancing their own transmission. In a Perspective by Read and Thomas, they discuss how McMeniman et al. (2) report a major step in a lateral development of this approach. They have infected the mosquito species that transmit dengue viruses to humans with an inheritance-distorting bacterium that kills mosquitoes likely to be infectious.
Andrew F. Read (Pennsylvania State University;Center for Infectious Disease Dynamics, Department of Biology); Matthew B. Thomas (Pennsylvania State University;Center for Infectious Disease Dynamics, Department of Entomology, Pennsylvania State University, University Park, PA 16802, USA.)
Adult mosquitoes were collected with CDC traps baited with CO2, and potential breeding sites were surveyed for immature stages. Morphological identification of 1,432 adult mosquitoes and 85 larvae revealed the presence of 10 species: Anopheles atroparvus, An. algeriensis, Coquillettidia richiardii, Culex modestus, Cx. pipiens, Cx. theileri, Cx. univittatus, Culiseta longiareolata, Aedes caspius and Ae. detritus. Adult mosquito peak densities were recorded in July, contrasting with null larval breeding in the same month in the surveyed biotopes. Most abundant species were Cx. pipiens (52%, Cx. theileri (29% and Ae. caspius (11%. Lagoon Salgados and Quinta das Salinas, exhibited the highest similarity of culicid fauna, despite being most distant from each other, Female mosquitoes (1,249 specimens screened by RT-PCR, did not reveal WNV products. However, previous detection of WNV activity in this area, susceptible to re-introductions, demands for continued vigilance.
This activity is designed to help students understand the complexity of nature by utilizing an online illustration of the ways in which various elements of a rainforest ecosystem are interconnected. Students will map the online habitat and create their own hyperlink habitat, either in print or on the Web, for a local ecosystem. When they are finished, they can submit their work to the Discovery Channel School.
The mosquito fauna in many areas of western Uganda has never been studied and is currently unknown. One area, Bwamba County, has been previously studied and documented but the species lists have not been updated for >40 yr. This paucity of data makes it difficult to determine which arthropod-borne viruses pose a risk to human or animal populations. Using CO2 baited-light traps, from 2008 through 2010, 67,731 mosquitoes were captured at five locations in western Uganda including Mweya, Sempaya, Maramagambo, Bwindi (BINP), and Kibale (KNP). Overall, 88 mosquito species, 7 subspecies, and 7 species groups in 10 genera were collected. The largest number of species was collected at Sempaya (65 species), followed by Maramagambo (45), Mweya (34), BINP (33), and KNP (22). However, species diversity was highest in BINP (Simpson's Diversity Index 1-D = 0.85), followed by KNP (0.80), Maramagambo (0.79), Sempaya (0.67), and Mweya (0.56). Only six species Aedes (Aedimorphus) cumminsii (Theobald), Aedes (Neomelaniconion) circumluteolus (Theobald), Culex (Culex) antennatus (Becker), Culex (Culex) decens group, Culex (Lutzia) tigripes De Grandpre and De Charmoy, and Culex (Oculeomyia) annulioris (Theobald), were collected from all five sites suggesting large differences in species composition among sites. Four species (Aedes (Stegomyia) metallicus (Edwards), Anopheles (Cellia) rivulorum Leeson, Uranotaenia (Uranotaenia) chorleyi (Edwards), and Uranotaenia (Uranotaenia) pallidocephala (Theobald) and one subspecies (Aedes (Stegomyia) aegypti formosus (Walker)) were collected in Bwamba County for the first time. This study represents the first description of the mosquito species composition of Mweya, Maramagambo, BINP, and KNP. A number of morphological variations were noted regarding the postspiracular scales, hind tibia, and sternites that make Culex (Culex) neavei (Theobald) challenging to identify. At least 50 species collected in this study have previously been implicated in the transmission of arboviruses of public health importance suggesting a high potential for maintenance and transmission of a wide variety of arboviruses in western Uganda. PMID:23270157
Mutebi, J-P; Crabtree, M B; Kading, R C; Powers, A M; Lutwama, J J; Miller, B R
This article reviews the various types of larval habitat of the malaria vector Anopheles philippinensis Ludlow in Bangladesh and characterizes its breeding ecology. Discussed also are the possible implications of the environmental changes on its breeding habitats resulting from intensified land use brought about by population increase and developments in irrigation and water resources.
Wildlife on isolated oceanic islands is highly susceptible to the introduction of pathogens. The recent establishment in the Galápagos Islands of the mosquito Culex quinquefasciatus, a vector for diseases such as avian malaria and West Nile fever, is considered a serious risk factor for the archipelago's endemic fauna. Here we present evidence from the monitoring of aeroplanes and genetic analysis that C. quinquefasciatus is regularly introduced via aircraft into the Galápagos Archipelago. Genetic population structure and admixture analysis demonstrates that these mosquitoes breed with, and integrate successfully into, already-established populations of C. quinquefasciatus in the Galápagos, and that there is ongoing movement of mosquitoes between islands. Tourist cruise boats and inter-island boat services are the most likely mechanism for transporting Culex mosquitoes between islands. Such anthropogenic mosquito movements increase the risk of the introduction of mosquito-borne diseases novel to Galápagos and their subsequent widespread dissemination across the archipelago. Failure to implement and maintain measures to prevent the human-assisted transport of mosquitoes to and among the islands could have catastrophic consequences for the endemic wildlife of Galápagos.
Bataille, Arnaud; Cunningham, Andrew A.; Cedeno, Virna; Cruz, Marilyn; Eastwood, Gillian; Fonseca, Dina M.; Causton, Charlotte E.; Azuero, Ronal; Loayza, Jose; Martinez, Jose D. Cruz; Goodman, Simon J.
In times of rapid global and unforeseeable environmental changes, there is an urgent need for a sustainable cattle breeding policy, based on a global view. Most of the indigenous breeds are specialized in a particular habitat or production system but are rapidly disappearing. Thus, they represent an important resource to meet present and future breeding objectives. Based on 105 microsatellites, we obtained thorough information on genetic diversity and population structure of 16 cattle breeds that cover a geographical area from the domestication centre near Anatolia, through the Balkan and alpine regions, to the North-West of Europe. Breeds under strict artificial selection and indigenous breeds under traditional breeding schemes were included. The overall results showed that the genetic diversity is widespread in Busa breeds in the Anatolian and Balkan areas, when compared with the alpine and north-western European breeds. Our results reflect long-term evolutionary and short-term breeding events very well. The regular pattern of allele frequency distribution in the entire cattle population studied clearly suggests conservation of rare alleles by conservation of preferably unselected traditional breeds with large effective population sizes. From a global and long-term conservation genetics point of view, the native and highly variable breeds closer to the domestication centre could serve as valuable sources of genes for future needs, not only for cattle but also for other farm animals. PMID:19659482
Medugorac, Ivica; Medugorac, Ana; Russ, Ingolf; Veit-Kensch, Claudia E; Taberlet, Pierre; Luntz, Bernhard; Mix, Henry M; Förster, Martin
Mosquito control ditches designed to increase tidal circulation are widely used as a physical control alternative to insecticidal applications The impact of such ditching on Pacific Coast marshlands was largely unknown before this five-year study of impact in two types of San Francisco Bay salt marshes, a Salicornia virginica (pickleweed) monoculure and a mixed vegetation marsh Results of our studies suggest that ditches cause less environmental disturbance than insecticidal applications The article describes the following environmental consequences of ditching for mosquito control: increased tidal flushing of soils occurs adjacent to ditches compared with that in the open marsh, thereby reducing ground water and soil surface salinities and water table height; primary productivity of S. virginica, as determined by both the harvest method and infrared photographic analysis, is higher directly adjacent to ditches than in the open marsh, distribution of selected arthropod populations is similar at ditches and natural channels, although arthropod community response differs seasonally; aquatic invertebrate biomass is similar within ditched and natural ponds, but diversity is lower in ditched habitats, ditching increases fish diversity and density by improving fish access from tidal channels; ditches provide additional salt marsh song sparrow habitat, although ditches are less preferred than natural channels or sloughs. Management criteria can be used to design ditches that provide effective mosquito control and reduced environmental impact
Resh, Vincent H.; Balling, Steven S.
Full Text Available Community involvement in mosquito management programs provides more sustainable and effective organization and service. A door to door survey in Wayne County, NC carried out by student volunteers, resulted in 60 household responses. Residents had not previously experienced outreach from the county (88%, and 95% of them thought the student door to door survey was an effective form of outreach. One third of the residents thought mosquitoes were severe where they lived, but only 9% thought they had any containers in their yard that might breed mosquitoes. Only 15% of the residents were concerned about mosquito borne diseases. These responses provide evidence that outreach and education on mosquito control and diseases were necessary steps for future mosquito control community planning.
A 3-year study was conducted to assess mosquito production in structural stormwater Best Management Practices (BMPs) installed by the California Department of Transportation in San Diego and Los Angeles Counties. Thirty-seven BMPs were monitored weekly for presence and relative abundance of immature mosquitoes and for conditions conducive to mosquito production. Species identified were Aedes squamiger, Anopheles franciscanus, An. hermsi, Culex quinquefasciatus, Cx. stigmatosoma, Cx. tarsalis, Culiseta incidens, and Cs. inornata. Structures designed with accessible, permanent sources of standing water in sumps, vaults, or basins were observed to support immatures all year. In BMPs intended to drain rapidly and completely, observed larval habitats resulted from design features, component failure, construction flaws, and non-stormwater runoff flows. Specific nonchemical mitigation measures to minimize or eliminate mosquito production were developed, implemented, and evaluated. This study provides a 1st assessment of mosquito production, species composition, and nonchemical control measures in structural stormwater BMPs in southern California. PMID:18437817
Metzger, Marco E; Myers, Charles M; Kluh, Susanne; Wekesa, J Wakoli; Hu, Renjie; Kramer, Vicki L
Fluctuaciones estacionales y temporales de la densidad larvaria de Anopheles darlingi Root (Diptera: Culicidae) y familias de insectos asociados al hábitat en El Granzón, Parroquia San Isidro, municipio Sifontes del estado Bolívar, Venezuela / Seasonal and temporal fluctuations of larval densites of Anopheles darlingi Root (Diptera: Culicidae) and insects associated to the habitat in San Isidro Parish, Sifontes municipality, Bolívar state, Venezuela
Full Text Available SciELO Venezuela | Language: Spanish Abstract in spanish Anopheles darlingi Root ha sido considerado en condiciones naturales como el principal vector de la malaria humana en América del sur y también en Venezuela, principalmente en los estados Bolívar y Amazonas, donde se produce el 90% de la malaria del país. Durante un mes (Junio de 1999) se realizaron [...] muestreos en criaderos de mosquitos en siete localidades del área minera de San Isidro municipio Sifontes, estado Bolívar. Los sitios de muestreo fueron clasificados a priori en cuatro tipos de hábitat larvario: quebradas, lagunas, ríos, pantanos (herbáceo o arbóreo). En cada criadero se tomaron 30 muestras con un cucharón para colectar larvas de Anopheles. Simultáneamente al muestreo de larvas se midieron cuatro variables físico-químicas del criadero: pH, oxígeno disuelto, temperatura y profundidad del criadero. Asimismo, en un criadero de An. darlingi (quebrada con sombra), ubicado en la localidad de El Granzón, se llevó a cabo un estudio longitudinal, durante un año entre Julio de 1999 y Junio del 2000. En dicho criadero, se colectaron mensualmente larvas de An. darlingi e insectos acuáticos asociados. Las correlaciones entre la precipitación acumulada, la abundancia de estos insectos y la abundancia de larvas de An. darlingi, se establecieron mediante el análisis no paramétrico de correlación de Spearman (Spearman rank correlation). En el hábitat seleccionado, los resultados del análisis revelaron la presencia de una correlación negativa y significativa entre la abundancia de larvas de An. darlingi y la precipitación acumulada el mes anterior a la colecta. En esa misma localidad, la precipitación acumulada el mes anterior a la colecta, se correlacionó positivamente con la abundancia de la familia Naucoridae (Hemiptera). Asimismo, la abundancia de larvas de An. darlingi presentó una correlación negativa y significativa con la abundancia de la familia Naucoridae. En este hábitat (quebrada del Granzón), la densidad de larvas An. darlingi fue mayor en los meses de menor precipitación, aunque tanto en la época de menor precipitación como en la temporada lluviosa, hubo presencia de larvas de esta especie. Por otro lado, el criadero típico de An. darlingi, donde éste presentó su mayor abundancia y hubo presencia de larvas durante todo el año, fue clasificado como ?Quebrada con sombra?. Esta presentó mucha sombra (90-100%), abundante materia orgánica sumergida o flotante (hojarasca, palitos, hojas, semillas), profundidad promedio de 65,22 cm, un pH promedio de 6,16, contenido medio de oxigeno disuelto de 6,40 g/L y una temperatura promedio del agua de 26ºC. Abstract in english Anopheles darlingi Root has been considered under natural conditions as human malaria?s principal vector in South America. In Venezuela, Amazonas and Bolivar States, it is responsible for 90 % of malaria cases reported in the country. Field surveys and mosquito larvae sampling of mosquito breeding s [...] ites in mining areas, were carried out in seven localities of Sifontes county, Bolívar state during one month, between 2 and 29 June 1999. The breeding sites were a priori classified into four larval habitat categories: lagoons, streams, rivers and herbaceous swamps. At each breeding site, 30 dips for mosquito larvae samples were made. Simultaneously with mosquito larvae sampling, four selected variables of water were measured: temperature, dissolved oxygen, pH and water depth. On the other hand, a longitudinal study was carried out in the typical An. darlingi breeding site (shaded streams) in El Granzón (Sifontes county). Field surveys of mosquito larvae and aquatic insects were carried out in the same breeding site over a one-year period (July, 1999 to June, 2000). At this breeding site, Anopheles larvae and aquatic insects were collected monthly. During the study, 12 samples were taken from this larval habitat of An. darlingi. Seasonal and temporal variations of An. darlingi larvae and aquatic insects were determined. Relati
Berti-Moser, Jesús; González-Rivas, Julio; Navarro, Edith.
Full Text Available Objective: The ability of the native larvivorous fish Aplocheilus panchax (Hamilton, 1822 (Cyprinodontiformes:Aplocheilidae as predator of mosquito larvae was assessed under laboratory conditions using multiple prey andhabitat conditions.Methods: The consumption of larvae of the mosquito Culex quinquefasciatus Say 1823 (Diptera: Culicidae byA. panchax was evaluated in the presence of tubificid worms and chironomid larvae under complex and simplehabitat conditions. The number of mosquito larvae consumed in comparison to other prey types was noted andan index of prey selectivity was used to evaluate the preference for mosquito larvae.Results: Aphlocheilus panchax consumed 53 to 65 mosquito larvae in a three hour feeding bout contrast to 29–38 tubificid worms and 43–62 chironomid larvae depending on the habitat conditions. The prey consumptiondiffered significantly between the habitats and the prey type. The index of prey selectivity was positive for Cx.quinquefasciatus larvae over other alternative prey in all the habitat conditions.Conclusion: It is apparent from the study that the larvivorous fish A. panchax can be employed for biologicalregulation of mosquitoes in rice-fields and similar wetlands where the multiple prey choices are available undercomplex habitat conditions. However, field studies including other prey species will be required to substantiatethis finding
Barnali Manna , Gautam Aditya & Samir Banerjee
In order to classify mosquito immature stage habitats, samples were taken in 42 localities of Córdoba Province, Argentina, representing the phytogeographic regions of Chaco, Espinal and Pampa. Immature stage habitats were described and classified according to the following criteria: natural or artificial; size; location related to light and neighboring houses; vegetation; water: permanence, movement, turbidity and pH. Four groups of species were associated based on the habitat similarity by ...
Many animal populations continue to decline despite occurring in protected areas or on sympathetically managed sites. Frequently, this is because a specific habitat patch may not fulfil all the niche requirements of a threatened species. For instance, species often move between, and make use of, multiple habitat types for breeding, roosting and feeding within the same landscape. These cross-habitat interactions present a challenge for conservation. Here we quantify how the habitat associations of individual species and assemblages occurring within two distinct but adjacent habitat types (moorland and farmland) determine a suite of density and richness indicators, using the bird community of the English uplands as a case study. There was a clear association between onsite avian density and richness and offsite habitat structure (e.g. vegetation height, percent cover of dominant plant species, land management practices). Although such effects are not universal across all species and assemblages, where present (for five farmland and three moorland indicators) the increase in explanatory power offered by including offsite habitat structure can be large. By constructing scenarios of possible changes to management practice on both moorland and farmland, we demonstrate a real conservation benefit can be obtained by altering management in offsite habitats. For example, reducing burning intensity on moorland can result in a five-fold increase in snipe Gallinago gallinago density on farmland, without an alteration in farmland habitat. For one species (Eurasian curlew Numenius arquata), we demonstrate the frequency with which birds move between and utilise farmland and moorland during the breeding season, and therefore the importance of both habitat types to maintaining population densities. The multiple habitat dependency phenomenon quantified here is common and not restricted to birds. The successful conservation of many threatened species will thus depend on coordinated cross-habitat management.
Dallimer, Martin; Skinner, Andrew M. J.
Abstract Background Limitations in the ability of organisms to tolerate environmental stressors affect their fundamental ecological niche and constrain their distribution to specific habitats. Evolution of tolerance, therefore, can engender ecological niche dynamics. Forest populations of the afro-tropical malaria mosquito Anopheles gambiae have been shown to adapt to historically unsuitable larval habitats polluted with decaying organic matter that are found in dens...
Tene Fossog Billy; Antonio-Nkondjio Christophe; Kengne Pierre; Njiokou Flobert; Besansky Nora J; Costantini Carlo
Full Text Available Abstract Background Genetically-modified (GM mosquitoes have been proposed as part of an integrated vector control strategy for malaria control. Public acceptance is essential prior to field trials, particularly since mosquitoes are a vector of human disease and genetically modified organisms (GMOs face strong scepticism in developed and developing nations. Despite this, in sub-Saharan Africa, where the GM mosquito effort is primarily directed, very little data is available on perspectives to GMOs. Here, results are presented of a qualitative survey of public attitudes to GM mosquitoes for malaria control in rural and urban areas of Mali, West Africa between the months of October 2008 and June 2009. Methods The sample consisted of 80 individuals - 30 living in rural communities, 30 living in urban suburbs of Bamako, and 20 Western-trained and traditional health professionals working in Bamako and Bandiagara. Questions were asked about the cause of malaria, heredity and selective breeding. This led to questions about genetic alterations, and acceptable conditions for a release of pest-resistant GM corn and malaria-refractory GM mosquitoes. Finally, participants were asked about the decision-making process in their community. Interviews were transcribed and responses were categorized according to general themes. Results Most participants cited mosquitoes as one of several causes of malaria. The concept of the gene was not widely understood; however selective breeding was understood, allowing limited communication of the concept of genetic modification. Participants were open to a release of pest-resistant GM corn, often wanting to conduct a trial themselves. The concept of a trial was reapplied to GM mosquitoes, although less frequently. Participants wanted to see evidence that GM mosquitoes can reduce malaria prevalence without negative consequences for human health and the environment. For several participants, a mosquito control programme was preferred; however a transgenic release that satisfied certain requirements was usually acceptable. Conclusions Although there were some dissenters, the majority of participants were pragmatic towards a release of GM mosquitoes. An array of social and cultural issues associated with malaria, mosquitoes and genetic engineering became apparent. If these can be successfully addressed, then social acceptance among the populations surveyed seems promising.
In many species mature individuals delay independent reproduction and may help others to reproduce. This behaviour is often explained through ecological constraints, although recently attention has also been paid to the variation in habitat quality. If the quality of vacant habitat influences the fitness trade-off between delaying reproduction and breeding independently, individuals should delay reproduction when conditions for breeding are poor. Yet, no study has experimentally manipulated h...
The earliest research efforts on using genetic methods for the control of mosquitoes and biting flies concentrated on the evaluation of the sterile insect technique (SIT). Several successful, but generally small scale, research efforts with mosquitoes clearly documented that either chemosterilized or radiation sterilized males were effective in causing a level of genetic load that would be sufficient for the reduction or eradication of natural populations of several species. Genetic sexing strains of several species of mosquitoes have been assembled, and this aspect of breeding specialty strains is not a limiting factor in the implementation of SIT. In the largest field experiment, conducted with Anopheles albimanus in El Salvador during the 1970s, a genetic sexing strain was used operationally in a factory that produced one million sterile males per day over a one year period. Technical problems that would require extensive research of a practical nature before the implementation of SIT for mosquito control involve primarily better means for the rearing, sterilization and distribution of the insects. A successful experiment was conducted to eliminate the stable fly on the island of St. Croix, the United States Virgin Islands, and since this work in the 1970s, genetic sexing strains have been developed. A considerable amount of effort was expended on the synthesis of chromosome aberrations for the control of mosquitoes. Although the results of experimental trials indicated that aberration bearing insects could effectively inject a genetic load into the natural population, no large scale tests have ever been conducted to evaluate fully the real effectiveness of induced chromosomal aberrations. More recently, most of the research work in genetic control has been aimed at the use of recombinant DNA techniques for the development of new technology. All of these topics and an assessment of their value are discussed. (author). 30 refs
The abundance and species composition of adult mosquitoes collected by carbon dioxide-baited suction traps and gravid traps in western Los Angeles County, CA, were compared before and during a strong El Niño--Southern Oscillation (ENSO) cycle from December 1996 until November 1999. Following El Niño conditions in the winter 1997-1998, adult host-seeking mosquito abundance during spring was twice that observed during spring 1997 and species composition favored cool-weather mosquitoes such as Culiseta incidens and Culex tarsalis. The comparatively cool temperatures from early April until early June and increased rainfall of the 1998 El Niño negatively affected warm-weather mosquitoes such as Culex quinquefasciatus that inhabit eutrophic habitats such as urban storm drains. Gravid mosquito abundance during the early summer following El Niño conditions also increased 2- to 3-fold relative to 1997, but gravid mosquito species composition was not significantly affected by ENSO cycles, reflecting an inherent bias of gravid traps to collect predominantly Cx. quinquefasciatus. Relative to spring 1997, host-seeking and gravid mosquito abundances were reduced 3- to 7-fold from March until June 1999 under the comparatively dry La Niña conditions. The increased abundance and prolonged host-seeking activity of Cx. tarsalis during the spring and early summer following a strong El Niño may have a significant impact on public health in urban southern California because this mosquito is an important arbovirus vector and constructed wetlands in urban areas may increase suitable, comparatively permanent developmental sites for important mosquito vectors such as Cx. tarsalis that are usually rare in urban environments. PMID:18697303
Heft, David E; Walton, William E
Larvae of Culex (Lutzia) Fuscanus were collected from ovitraps in a natural breeding site. Collected larvae were used to establish a self-mating colony, and larval progeny were then used to determine their predatory efficacy on larvae of 3 vector mosquito species, Aedes aegypti, Anopheles subpictus, and Cx. tritaeniorhynchus. Statistical analysis revealed that Cx. fuscanus showed greater feeding efficacy for Ae. aegypti than for Cx. tritaeniorhynchus and An. subpictus. The natural predatory role of this species can potentially be exploited for biological control of mosquito vectors in Sri Lanka. PMID:23923332
Surendran, Sinnathamby N; Jude, Pavilupillai J; Thavaranjit, Arulanantham Christie; Eswaramohan, Thampoe; Vinobaba, Muthuludchumy; Ramasamy, Ranjan
Background Mosquitoes transmit serious human diseases, causing millions of deaths every year. Use of synthetic insecticides to control vector mosquitoes has caused physiological resistance and adverse environmental effects in addition to high operational cost. Insecticides of botanical origin have been reported as useful for control of mosquitoes. Azadirachta indica (Meliaceae) and its derived products have shown a variety of insecticidal properties. The present paper discusses the larvicidal activity of neem-based biopesticide for the control of mosquitoes. Methods Larvicidal efficacy of an emulsified concentrate of neem oil formulation (neem oil with polyoxyethylene ether, sorbitan dioleate and epichlorohydrin) developed by BMR & Company, Pune, India, was evaluated against late 3rd and early 4th instar larvae of different genera of mosquitoes. The larvae were exposed to different concentrations (0.5–5.0 ppm) of the formulation along with untreated control. Larvicidal activity of the formulation was also evaluated in field against Anopheles, Culex, and Aedes mosquitoes. The formulation was diluted with equal volumes of water and applied @ 140 mg a.i./m2 to different mosquito breeding sites with the help of pre calibrated knapsack sprayer. Larval density was determined at pre and post application of the formulation using a standard dipper. Results Median lethal concentration (LC50) of the formulation against Anopheles stephensi, Culex quinquefasciatus and Aedes aegypti was found to be 1.6, 1.8 and 1.7 ppm respectively. LC50 values of the formulation stored at 26°C, 40°C and 45°C for 48 hours against Ae. aegypti were 1.7, 1.7, 1.8 ppm while LC90 values were 3.7, 3.7 and 3.8 ppm respectively. Further no significant difference in LC50 and LC90 values of the formulation was observed against Ae. aegypti during 18 months storage period at room temperature. An application of the formulation at the rate of 140 mg a.i./m2 in different breeding sites under natural field conditions provided 98.1% reduction of Anopheles larvae on day 1; thereafter 100% reduction was recorded up to week 1 and more than 80% reduction up to week 3, while percent reduction against Culex larvae was 95.5% on day 1, and thereafter 80% reduction was achieved up to week 3. The formulation also showed 95.1% and, 99.7% reduction of Aedes larvae on day 1 and day 2 respectively; thereafter 100% larval control was observed up to day 7. Conclusion The neem oil formulation was found effective in controlling mosquito larvae in different breeding sites under natural field conditions. As neem trees are widely distributed in India, their formulations may prove to be an effective and eco-friendly larvicide, which could be used as an alternative for malaria control.
Dua, Virendra K; Pandey, Akhilesh C; Raghavendra, Kamaraju; Gupta, Ashish; Sharma, Trilochan; Dash, Aditya P
Full Text Available Abstract Background Mosquitoes transmit serious human diseases, causing millions of deaths every year. Use of synthetic insecticides to control vector mosquitoes has caused physiological resistance and adverse environmental effects in addition to high operational cost. Insecticides of botanical origin have been reported as useful for control of mosquitoes. Azadirachta indica (Meliaceae and its derived products have shown a variety of insecticidal properties. The present paper discusses the larvicidal activity of neem-based biopesticide for the control of mosquitoes. Methods Larvicidal efficacy of an emulsified concentrate of neem oil formulation (neem oil with polyoxyethylene ether, sorbitan dioleate and epichlorohydrin developed by BMR & Company, Pune, India, was evaluated against late 3rd and early 4th instar larvae of different genera of mosquitoes. The larvae were exposed to different concentrations (0.5–5.0 ppm of the formulation along with untreated control. Larvicidal activity of the formulation was also evaluated in field against Anopheles, Culex, and Aedes mosquitoes. The formulation was diluted with equal volumes of water and applied @ 140 mg a.i./m2 to different mosquito breeding sites with the help of pre calibrated knapsack sprayer. Larval density was determined at pre and post application of the formulation using a standard dipper. Results Median lethal concentration (LC50 of the formulation against Anopheles stephensi, Culex quinquefasciatus and Aedes aegypti was found to be 1.6, 1.8 and 1.7 ppm respectively. LC50 values of the formulation stored at 26°C, 40°C and 45°C for 48 hours against Ae. aegypti were 1.7, 1.7, 1.8 ppm while LC90 values were 3.7, 3.7 and 3.8 ppm respectively. Further no significant difference in LC50 and LC90 values of the formulation was observed against Ae. aegypti during 18 months storage period at room temperature. An application of the formulation at the rate of 140 mg a.i./m2 in different breeding sites under natural field conditions provided 98.1% reduction of Anopheles larvae on day 1; thereafter 100% reduction was recorded up to week 1 and more than 80% reduction up to week 3, while percent reduction against Culex larvae was 95.5% on day 1, and thereafter 80% reduction was achieved up to week 3. The formulation also showed 95.1% and, 99.7% reduction of Aedes larvae on day 1 and day 2 respectively; thereafter 100% larval control was observed up to day 7. Conclusion The neem oil formulation was found effective in controlling mosquito larvae in different breeding sites under natural field conditions. As neem trees are widely distributed in India, their formulations may prove to be an effective and eco-friendly larvicide, which could be used as an alternative for malaria control.
Dua Virendra K
Wildlife managers increasingly are using remotely sensed imagery to improve habitat delineations and sampling strategies. Advances in remote sensing technology, such as hyperspectral imagery, provide more information than previously was available with multispectral sensors. We evaluated accuracy of high-resolution hyperspectral image classifications to identify wetlands and wetland habitat features important for Columbia spotted frogs (Rana luteiventris) and compared the results to multispectral image classification and United States Geological Survey topographic maps. The study area spanned 3 lake basins in the Salmon River Mountains, Idaho, USA. Hyperspectral data were collected with an airborne sensor on 30 June 2002 and on 8 July 2006. A 12-year comprehensive ground survey of the study area for Columbia spotted frog reproduction served as validation for image classifications. Hyperspectral image classification accuracy of wetlands was high, with a producer's accuracy of 96 (44 wetlands) correctly classified with the 2002 data and 89 (41 wetlands) correctly classified with the 2006 data. We applied habitat-based rules to delineate breeding habitat from other wetlands, and successfully predicted 74 (14 wetlands) of known breeding wetlands for the Columbia spotted frog. Emergent sedge microhabitat classification showed promise for directly predicting Columbia spotted frog egg mass locations within a wetland by correctly identifying 72 (23 of 32) of known locations. Our study indicates hyperspectral imagery can be an effective tool for mapping spotted frog breeding habitat in the selected mountain basins. We conclude that this technique has potential for improving site selection for inventory and monitoring programs conducted across similar wetland habitat and can be a useful tool for delineating wildlife habitats. ?? 2010 The Wildlife Society.
Shive, J. P.; Pilliod, D. S.; Peterson, C. R.
The ability of nest predation to influence habitat settlement decisions in birds is widely debated, despite its importance in limiting fitness. Here, we experimentally manipulated nest predation risk across a landscape and asked the question, do migratory birds assess and respond to variation in nest predation risk when choosing breeding habitats? We examined habitat preference by quantifying the density and settlement date of eight species of migratory passerines breeding in areas with and without intact nest predator communities. We found consistently more individuals nesting in areas with reduced nest predation than in areas with intact predator assemblages, although predation risk had no influence on settlement or breeding phenology. Additionally, those individuals occupying safer nesting habitats exhibited increased singing activity. These findings support a causal relationship between habitat choice and nest predation risk and suggest the importance of nest predation risk in shaping avian community structure and breeding activity. ?? 2006 by The University of Chicago. All rights reserved.
Fontaine, J. J.; Martin, T. E.
Larval mosquito habitats of potential malaria vectors and related species of Anopheles from three provinces (Gyeonggi, Gyeongsangbuk, Chungcheongbuk Provinces) of the Republic of Korea were surveyed in 2007. This study aimed to determine the species compo...
H. C. Kim L. M. Rueda S. Chong T. A. Klein T. L. Brown
From March 2004 to February 2006, a mosquito survey was conducted in Makka Al Mukarrama Region, in the western part of Saudi Arabia, and 19 species which belong to 4 genera, were collected: Aedes (2 species), Anopheles (8 species), Culex (8 species) and Culiseta (1 species). The mosquitoes were Aedes caspius, Ae. aegypti, Anopheles d'thali, An. gambiae, An. multicolor, An. rhodesiensis, An. sergenti, An. stephensi, An. subpictus, An. turkhudi, Culex arbieeni, Cx. laticinctus, Cx. pipiens, Cx. quinquefasciatus, Cx. sinaiticus, Cx. tigripes, Cx. tritaeniorhynchus, Cx. univittatus and Culiseta longiareolata. Cx. arbieeni was reported for the first time in Saudi Arabia from Al Taif District. The physical properties of water of mosquito's larval breeding sites showed the total dissolved salts (TDS) varied between 70-15552 ppm, pH ranged between 5.4-11.2 and water temperature varied between 15 degrees C in winter to 40.7 degrees C in summer. There was no correlation between these physical properties and the distribution of mosquito larvae. Light traps collected 1858 mosquitoes, and adult Culex were the most prevalent as 1658 (89.24%) were collected, followed by 121 (6.51%) Aedes, 68 (3.66%) Anopheles and 11 (0.59%) Culiseta. The effects of temperature and rainfall on seasonal abundance of mosquitoes in the study area are discussed. PMID:20120761
Alahmed, A M; Al Kuriji, M A; Kheir, S M; Alahmedi, S A; Al Hatabbi, M J; Al Gashmari, M A M
The enormous burden placed on populations worldwide by mosquito-borne diseases, most notably malaria and dengue, is currently being tackled by the use of insecticides sprayed in residences or applied to bednets, and in the case of dengue vectors through reduction of larval breeding sites or larviciding with insecticides thereof. However, these methods are under threat from, amongst other issues, the development of insecticide resistance and the practical difficulty of maintaining long-term community-wide efforts. The sterile insect technique (SIT), whose success hinges on having a good understanding of the biology and behaviour of the male mosquito, is an additional weapon in the limited arsenal against mosquito vectors. The successful production and release of sterile males, which is the mechanism of population suppression by SIT, relies on the release of mass-reared sterile males able to confer sterility in the target population by mating with wild females. A five year Joint FAO/IAEA Coordinated Research Project brought together researchers from around the world to investigate the pre-mating conditions of male mosquitoes (physiology and behaviour, resource acquisition and allocation, and dispersal), the mosquito mating systems and the contribution of molecular or chemical approaches to the understanding of male mosquito mating behaviour. A summary of the existing knowledge and the main novel findings of this group is reviewed here, and further presented in the reviews and research articles that form this Acta Tropica special issue. PMID:24252487
Lees, Rosemary Susan; Knols, Bart; Bellini, Romeo; Benedict, Mark Q; Bheecarry, Ambicadutt; Bossin, Hervé Christophe; Chadee, Dave D; Charlwood, Jacques; Dabiré, Roch K; Djogbenou, Luc; Egyir-Yawson, Alexander; Gato, René; Gouagna, Louis Clément; Hassan, Mo'awia Mukhtar; Khan, Shakil Ahmed; Koekemoer, Lizette L; Lemperiere, Guy; Manoukis, Nicholas C; Mozuraitis, Raimondas; Pitts, R Jason; Simard, Frederic; Gilles, Jeremie R L
This online portal features a research project funded by The Grand Challenges in Global Health Initiative to develop new strategies to control mosquitoes that transmit human disease. Specifically, the project is focused on a method to reduce dengue transmission using naturally occurring bacterial symbionts that reduce mosquito life span. The site includes a background of this work, participating research programs and researchers, project publications, current progress, news and events, and FAQs.
Initiative, The G.
Research on gene expression in mosquitoes is motivated by both basic and applied interests. Studies of genes involved in hematophagy, reproduction, olfaction, and immune responses reveal an exquisite confluence of biological adaptations that result in these highly-successful life forms. The requirement of female mosquitoes for a bloodmeal for propagation has been exploited by a wide diversity of viral, protozoan and metazoan pathogens as part of their life cycles. Identifying genes involved i...
Chen, Xlao-guang; Mathur, Geetika; James, Anthony A.
We developed a habitat suitability model for predicting nest locations of breeding Northern Goshawks (Accipiter gentilis) in the high-elevation mixed forest and shrub-steppe habitat of south-central Idaho, USA. We used elevation, slope, aspect...
Miller, Robert A.; Carlisle, Jay D.; Bechard, Marc J.; Dena Santini
Full Text Available The goal of this study was to evaluate the effectiveness of a public health educational campaign to reduce backyard mosquito-larval habitats. Three communities each, within two New Jersey counties, were randomly selected to receive: (1 both education and mosquito control, (2 education only, and (3 no education or mosquito control. Four separate educational events included a 5-day elementary school curriculum in the spring, and three door to door distributions of educational brochures. Before and after each educational event, the numbers of mosquito-larval container habitats were counted in 50 randomly selected homes per study area. Container surveys allowed us to measure source reduction behavior. Although we saw reductions in container habitats in sites receiving education, they were not significantly different from the control. Our results suggest that traditional passive means of public education, which were often considered the gold standard for mosquito control programs, are not sufficient to motivate residents to reduce backyard mosquito-larval habitats.
The aim of this study was to evaluate mosquito abundance, species diversity, larval and adult population dynamics in seven lagoons integrated in the wetland coastal system of the Algarve, Portugal, in the summer of 2007, as well as the screening of these for West Nile virus (WNV). WNV has been isolated from mosquitoes in this region, in the summer of 2004, next to the putative area of infection of two linked human WN cases. Adult mosquitoes were collected with CDC traps baited with CO(2), and potential breeding sites were surveyed for immature stages. Morphological identification of 1,432 adult mosquitoes and 85 larvae revealed the presence of 10 species: Anopheles atroparvus, Anopheles algeriensis, Coquillettidia richiardii, Culex modestus, Culex pipiens, Culex theileri, Culex univittatus, Culiseta longiareolata, Aedes caspius, and Aedes detritus. Adult mosquito peak densities were recorded in July, contrasting with null larval breeding in the same month in the surveyed biotopes. Most abundant species were C. pipiens (52%), C. theileri (29%), and A. caspius (11%). Lagoon Salgados and Quinta das Salinas, exhibited the highest similarity of culicid fauna, despite being most distant from each other, Female mosquitoes (1,249 specimens) screened by RT-PCR, did not reveal WNV products. However, previous detection of WNV activity in this area, susceptible to re-introductions, demands for continued vigilance. PMID:22347862
Freitas, Ferdinando B; Novo, Maria Teresa; Esteves, Aida; de Almeida, A Paulo G
Thousands of flooded swimming pools were abandoned in New Orleans following Hurricane Katrina and provided a natural experiment to examine colonization of a novel aquatic habitat by mosquito larvae and their aquatic predators. We conducted a randomized survey of flooded swimming pools in two neighborhoods in January 2006 and found that 64% contained mosquito larvae, 92% contained predatory invertebrates, and 47% contained fishes. We collected 12,379 immature mosquitoes representing five species, primarily Culiseta inornata, and secondarily, the arboviral vector Culex quinquefasciatus. Dragonfly nymphs in the families Aeshnidae and Libellulidae were the most common predatory invertebrates collected among a total of 32 non-mosquito invertebrate species. Eleven species of fishes were collected, with Gambusia affinis accounting for 76% of the catch. Diversity of fishes in swimming pools was positively correlated with proximity to a levee breach and the fish assemblage found in swimming pools was similar to that found along shorelines of Lake Pontchartrain and drainage canals that flooded the study area. Mosquito larvae were rare or absent from pools containing fishes; however, path analysis indicated that the presence of top predators or abundant competitors may somewhat mitigate the effect of Gambusia affinis on mosquito presence. PMID:18697320
Caillouët, Kevin A; Carlson, John C; Wesson, Dawn; Jordan, Frank
Pyriproxyfen, a juvenile hormone analogue, diflubenzuron, a chitin synthesis inhibitor, and azadirachtin, an ecdysone agonist, are three insect growth regulators (IGRs) considered as selective and effective insecticides for mosquitoes. Romanomermis iyengari (Welch) is a mosquito-parasitic mermithid that can provide biological control against many medically important mosquito species. The compatibility of these two control tactics was tested by evaluating the sublethal effects of exposure to IGR on nematode developmental stages (preparasitic, parasitic, and preparasitic + parasitic) using Culex pipiens larvae as the host. Sublethal concentrations of IGRs were 90 % emergence inhibition of host mosquito. Preparasitic exposure to pyriproxyfen, azadirachtin, and diflurbenzuron had no effect on infectivity, parasite load, sex ratio, or male size but reduced nematode female length and increased male sex ratio at one parasite/larva. When IGRs treatments were made against the parasitic and preparasitic + parasitic stages, pyriproxyfen and azadirachtin reduced R. iyengari infectivity, parasite load, and male nematode length, whereas pyriproxyfen exposure increased male sex ratio and reduced the female R. iyengari length. Thus, IGRs have significant negative impacts on different stages of mosquito mermithid that can destabilize the balance of host-parasite population interaction. Therefore, IGRs should be used with caution in mosquito habitats where these parasites have established. PMID:23180130
Suman, Devi Shankar; Brey, Christopher W; Wang, Yi; Sanad, Manar; Shamseldean, Muhammed S M; Gaugler, Randy
Mosquito control is being performed under chemical, biological and genetic and altogether it is called integrated vector control. In developing countries like India, chemical control has been given priority. Chemicals used as adulticide is becoming resistance among mosquitoes compared to larvicide. Further, the destruction of immature (larvae) stages of mosquitoes is as effective as its distribution is limited whereas adult mosquitoes turned to terrestrial mode of life and its distribution is based on its flight range, habitat, aggregation of man and animals. In this research paper, selective spray treatment over larvae of mosquitoes of a semi-infinite pool is analyzed using diffusion model. Spray chemical is conceived to spread on the surface with time and in space. A critical concentration of spray chemical is envisaged for assumed death of mosquito larvae. Diffusion is modeled Fick' law. Spray losses are lumped into a first order term. Analytical solution of the resulting partial differential equation for various values of diffusivity and loss rate constant are plotted and interpreted. The model would be useful to appraise beforehand how far and for how long spray would be effective and how much of spray chemical is required for effectiveness within specified distance and time.
Basker, P.; Kumar, T. Ramesh; Prabu, S. Milton; Hemalatha, S.; Elango, S.; Padmanabhan, P.; Asokan, R.
Full Text Available The author made ornithological observations during 2003 - 2010 in the middle basin of the river Arge?, and observed 122 breeding species that are included in 13 orders, 38 families and 83 genera. 96 of them are certainly breeding species and 26 are probably breeding species. The results of the researches were cumulated with the data from the Atlas of the Romanian breeding species. By reference to the Atlas data, it is noticeable that 95 of the 106 breeding species cited in the Atlas were again recorded. 27 new breeding species were identified. Regarding the occupied habitat, most of the breeding species (72% live in the terrestrial habitat. The summer visitor species and the sedentary species are preponderant; they are followed by the partially migrant species. 22 breeding species are listed in Annex I of the Birds Directive.
Abstract Background Preventing malaria by controlling mosquitoes in their larval stages requires regular sensitive monitoring of vector populations and intervention coverage. The study assessed the effectiveness of operational, community-based larval habitat surveillance systems within the Urban Malaria Control Programme (UMCP) in urban Dar es Salaam, Tanzania. Methods Cross-sectional surveys were carried out to assess the ability of community-owned resource per...
Chaki Prosper P; Govella Nicodem J; Shoo Bryson; Hemed Abdullah; Tanner Marcel; Fillinger Ulrike; Killeen Gerry F
A floating, slow-release, granular formulation of Bacillus sphaericus (Neide) was used to control mosquito larvae in two suburban areas of two tropical cities: Ouagadougou and Bobo-Dioulasso, Burkina Faso. A circular area of 2 km2, diameter 1,600 m, was treated in each city using a similar, smaller area 1 km away as an untreated control. Mosquito captures were made in houses in four concentric circles, from the periphery to the center; each circle was 50 m in width. Mosquitoes were captured in CDC light traps or from human landings. More than 95% of the mosquitoes were Culex quinquefasciatus (Say) (Diptera: Culicidae). The human landing catches provided twice as many mosquitoes as did the CDC traps/night/house. The treatments resulted in important reductions relative to the control area and to preintervention captures. The reduction was more prominent in the inner circle (up to 90%) than in the outer circle (50-70%), presumably because of the impact of immigrating mosquitoes from nontreated breeding sites around the intervention area. This effect was more pronounced for light trap catches than from human landings. The impact of treatment was also measured as the mean ratio of mosquito density in the two outer circles to that of the two inner circles. This ratio was approximately 1:1 before the intervention and reached 1:0.43 during the intervention. This comparison does not depend on the assumption that, in the absence of intervention, the mosquito population development in the two areas would have been identical, but does depend on the homogeneity of the intervention area. The study showed that it is possible to organize mosquito control in a tropical, urban environment by forming and rapidly training teams of young people to carry out the mosquito control mostly using a biopesticide that can be applied without any tools except an iron bar to lift lids on some cesspits. PMID:19198519
Skovmand, Ole; Ouedraogo, Thierry D A; Sanogo, Edith; Samuelsen, Helle; Toé, Lea P; Baldet, Thierry
A total of 6,500 mosquitoes were identified during a two-year survey (1999-2001) in Lebanon, and these belonged to twelve species: Culex pipiens, Cx. laticinctus, Cx. mimeticus, Cx. hortensis, Cx. judaicus, Aedes aegypti, Ae. cretinus, Ochlerotatus caspius, Oc. geniculatus, Oc. pulchritarsis, Culiseta longiareolata and Anopheles claviger. Culex pipiens was the most predominant species in Lebanon, collected indoors and outdoors. It was continuously abundant and active throughout the year. Culex judaicus was a small and rare mosquito and it is reported to occur for the first time in Lebanon. On the coastal areas, Ochlerotatus caspius was very common, and proved to be a complex of species as two forms were detected. One of the vectors of malaria, Anopheles claviger, was collected from May to September, from eight sites in Lebanon. Its breeding sites were restricted to fresh, cool, and clean water in pools and wells. Most of these breeding sites were in the populated Metn County where a few indigenous cases of malaria were reported from 1997-2000. This shows that the reported malaria cases were not imported, but caused by the bites of locally infected Anopheles females. PMID:16218210
Knio, K M; Markarian, N; Kassis, A; Nuwayri-Salti, N
Full Text Available Abstract Background For remote identification of mosquito habitats the first step is often to construct a discrete tessellation of the region. In applications where complex geometries do not need to be represented such as urban habitats, regular orthogonal grids are constructed in GIS and overlaid on satellite images. However, rice land vector mosquito aquatic habitats are rarely uniform in space or character. An orthogonal grid overlaid on satellite data of rice-land areas may fail to capture physical or man-made structures, i.e paddies, canals, berms at these habitats. Unlike an orthogonal grid, digitizing each habitat converts a polygon into a grid cell, which may conform to rice-land habitat boundaries. This research illustrates the application of a random sampling methodology, comparing an orthogonal and a digitized grid for assessment of rice land habitats. Methods A land cover map was generated in Erdas Imagine V8.7® using QuickBird data acquired July 2005, for three villages within the Mwea Rice Scheme, Kenya. An orthogonal grid was overlaid on the images. In the digitized dataset, each habitat was traced in Arc Info 9.1®. All habitats in each study site were stratified based on levels of rice stage Results The orthogonal grid did not identify any habitat while the digitized grid identified every habitat by strata and study site. An analysis of variance test indicated the relative abundance of An. arabiensis at the three study sites to be significantly higher during the post-transplanting stage of the rice cycle. Conclusion Regions of higher Anopheles abundance, based on digitized grid cell information probably reflect underlying differences in abundance of mosquito habitats in a rice land environment, which is where limited control resources could be concentrated to reduce vector abundance.
Kakoma Ibulaimu I
Full Text Available Abstract Background In many parts of the world, salt marshes play a key ecological role as the interface between the marine and the terrestrial environments. Salt marshes are also exceedingly important for public health as larval habitat for mosquitoes that are vectors of disease and significant biting pests. Although grid ditching and pesticides have been effective in salt marsh mosquito control, marsh degradation and other environmental considerations compel a different approach. Targeted habitat modification and biological control methods known as Open Marsh Water Management (OMWM had been proposed as a viable alternative to marsh-wide physical alterations and chemical control. However, traditional larval sampling techniques may not adequately assess the impacts of marsh management on mosquito larvae. To assess the effectiveness of integrated OMWM and marsh restoration techniques for mosquito control, we analyzed the results of a 5-year OMWM/marsh restoration project to determine changes in mosquito larval production using GIS and geostatistical methods. Methods The following parameters were evaluated using "Before-After-Control-Impact" (BACI design: frequency and geographic extent of larval production, intensity of larval production, changes in larval habitat, and number of larvicide applications. The analyses were performed using Moran's I, Getis-Ord, and Spatial Scan statistics on aggregated before and after data as well as data collected over time. This allowed comparison of control and treatment areas to identify changes attributable to the OMWM/marsh restoration modifications. Results The frequency of finding mosquito larvae in the treatment areas was reduced by 70% resulting in a loss of spatial larval clusters compared to those found in the control areas. This effect was observed directly following OMWM treatment and remained significant throughout the study period. The greatly reduced frequency of finding larvae in the treatment areas led to a significant decrease (~44% in the number of times when the larviciding threshold was reached. This reduction, in turn, resulted in a significant decrease (~74% in the number of larvicide applications in the treatment areas post-project. The remaining larval habitat in the treatment areas had a different geographic distribution and was largely confined to the restored marsh surface (i.e. filled-in mosquito ditches; however only ~21% of the restored marsh surface supported mosquito production. Conclusion The geostatistical analysis showed that OMWM demonstrated considerable potential for effective mosquito control and compatibility with other natural resource management goals such as restoration, wildlife habitat enhancement, and invasive species abatement. GPS and GIS tools are invaluable for large scale project design, data collection, and data analysis, with geostatistical methods serving as an alternative or a supplement to the conventional inference statistics in evaluating the project outcome.
Dempsey Mary E
A programme of surveillance was initiated in 1992, in the French Riviera, to detect a possible introduction of Aedes albopictus from Italy and to prevent nuisances caused by mosquitoes in the touristic localities of the Côte d'Azur. In five years, numerous mosquito breeding places have been located. Nine species have been collected: Anopheles claviger, An. plumbeus, Aedes geniculatus, Ae. vittatus, Culex hortensis, Cx. impudicus, Cx. pipiens, Culiseta fumipennis, Cs. longiareolata but no Ae. albopictus was found. Nuisances were mainly due to hypogean populations of Cx. pipiens. Breeding places in urban sites have been controlled or suppressed. The discovery of an important larval population of An. plumbeus in an urban area might further stress the importance of this species already suspected to transmit indigenous malaria in cities. PMID:10376290
Fauran, P; Marty, P; Izri, M A; Le Fichoux, Y
Mosquito species occurring in Bellary district, Karnataka, India were surveyed for Japanese encephalitis (JE) and West Nile virus (WNV) from 2001 to 2003. A total of 37 mosquito species in 6 genera were recovered from larval and adult habitats. Aedes, Anopheles and Culex were represented by 11 species each, Mansonia by 2 species, and Armigeres and Lutzia by a single species. A total of 68,506 mosquitoes belonging to 20 species were collected at dusk. Most (74.6%) were Cx. tritaeniorhynchus and occurred in 2 peaks of abundance in February (304 per man hour density [PMHD]) and October (465 PMHD). The mosquito fauna of Bellary district is not diverse, possibly because of the hot and dry climatic conditions in the area. PMID:18437807
Kanojia, P C; Jamgaonkar, A V
Full Text Available Abstract Research on sterile mosquito technology from 1955 to the 1980s provided a substantial body of knowledge on propagation and release of sterile mosquitoes. Radiation sterilisation and chemosterilisation have been used effectively to induce dominant lethality and thereby sterilise important mosquito vectors in the laboratory. Experimental releases of chemosterilised males provided complete control of Anopheles albimanus in a small breeding population (14-15 sq km in El Salvador. Releases of radiation sterilised males failed to control either Aedes aegypti or Anopheles quadrimaculatus in the USA. Releases of radiation-sterilised and chemosterilised male Culex quinquefasciatus in the USA and India were successful in some instances. Development of genetic sexing systems for Anopheles and improved physical separation methods for Culex have made it possible to rear and release males almost exclusively (> 99% minimizing the release of potential vectors, the females. Factors that affected efficacy in some field programmes included reduction of competitiveness by radiation, immigration of fertilized females from outside the release zones, and inability of laboratory-bred males to perform in the wild. Despite significant progress, institutional commitments to carry the process further were generally lacking in the late 1970s and until recently. Now, with renewed interest and support for further assessment of this technology, this paper summarizes the current knowledge base, prioritizes some areas of investigation, and challenges scientists and administrators to maintain an awareness of progress, remain realistic about the interpretation of new findings, and make decisions about the sterile insect technique on the basis of informed scientific documentation. Areas recommended for priority research status include the establishment of genetic sexing mechanisms that can be transferred to other mosquito species, re-examination of radiation sterilisation, aerial release technology and mass rearing.
Knols Bart GJ
Full Text Available Abstract Background In western Kenya, malaria remains one of the major health problems and its control remains an important public health measure. Malaria control is by either use of drugs to treat patients infected with malaria parasites or by controlling the vectors. Vector control may target the free living adult or aquatic (larval stages of mosquito. The most commonly applied control strategies target indoor resting mosquitoes. However, because mosquitoes spend a considerable time in water, targeting the aquatic stages can complement well with existing adult control measures. Methods Larval source management (LSM of malaria vectors was examined in two villages i.e. Fort Ternan and Lunyerere, with the aim of testing strategies that can easily be accessed by the affected communities. Intervention strategies applied include environmental management through source reduction (drainage of canals, land levelling or by filling ditches with soil, habitat manipulation (by provision of shading from arrow root plant, application of Bacillus thuringiensis var israelensis (Bti and the use of predatory fish, Gambusia affinis. The abundance of immature stages of Anopheles and Culex within intervention habitats was compared to that within non-intervention habitats. Results The findings show that in Fort Ternan no significant differences were observed in the abundance of Anopheles early and late instars between intervention and non-intervention habitats. In Lunyerere, the abundance of Anopheles early instars was fifty five times more likely to be present within non-intervention habitats than in habitats under drainage. No differences in early instars abundance were observed between non-intervention and habitats applied with Bti. However, late instars had 89?% and 91?% chance of being sampled from non-intervention rather than habitats under drainage and those applied with Bti respectively. Conclusion Most of these interventions were applied in habitats that arose due to human activities. Involvement of community members in control programs would be beneficial in the long term once they understand the role they play in malaria transmission. Apart from the need for communities to be educated on their role in malaria transmission, there is a need to develop and test strategies that can easily be accessed and hence be used by the affected communities. The proposed LSM strategies target outdoor immature mosquitoes and hence can complement well with control measures that target indoor resting vectors. Therefore inclusion of LSM in Integrated Vector Management (IVM program would be beneficial.
Imbahale Susan S
Abstract Background Half of the population of Africa will soon live in towns and cities where it can be protected from malaria by controlling aquatic stages of mosquitoes. Rigorous but affordable and scaleable methods for mapping and managing mosquito habitats are required to enable effective larval control in urban Africa. Methods A simple community-based mapping procedure that requires no electronic devices in the field was developed to facilitate routine larv...
Dongus Stefan; Nyika Dickson; Kannady Khadija; Mtasiwa Deo; Mshinda Hassan; Fillinger Ulrike; Drescher Axel W; Tanner Marcel; de Castro Marcia C; Killeen Gerry F
Full Text Available Mosquitoes are the vectors for the dreadful diseases of mankind. For control of larval stages of mosquito, herbal plant extracts/ botanical insecticides are being tried. In the present study aqueous extract of some traditional medicinal herbal plants i.e. Neem (Azadirechta indica, Tobacco (Nicotiana tabacum, Turmeric (Curcuma longa, Tulasi (Ocimum santum, and Ginger (Zingiber officinale were tested for their Larvicidal activity. The successful attempt is made to kill the larvae, the premature stage of mosquitoes by using safe and socio-economical herbal plant extract mixtures. Ginger+Tobacco, Neem+Tobbaco and Ginger Neem, Turmeric, Tobacco and Tulasi showed highest larvicidal activity. The results obtained show that this plant material exhibited larvicidal activity and could be considered as potent natural larvicidal agent without any toxic effects.
Chaudhari Priyanka S, Chaudhari SV* Jangam Sampada, Shinde JS, Wankhede Sneha
In this first paper of a series on mosquitoes of the mangrove forests of India, details of mosquito species recorded in Bhitarkanika, Orissa, are presented. Forty-three species of mosquitoes belonging to 21 subgenera and 13 genera, Aedes, Anopheles, Armigeres, Coquillettidia, Culex, Ficalbia, Heizmannia, Lutzia, Mansonia, Ochlerotatus, Toxorhynchites, Uranotaenia, and Verrallina, were recorded. Predominant larval habitat was the tree holes, from which 15 species were taken. Adults were mostly found resting in crab holes, tree holes, and hoof prints in the forest area and on walls in the guesthouse area. About 14 species were caught in light traps, while 19 species landed on humans for feeding. Ae. franciscoi and Oc. feegradei are 2 new country records for India. Ae. cancricomes and Cx. perplexus, known only from Andaman Islands of India, are new records for mainland India. PMID:16033113
Rajavel, A R; Natarajan, R; Vaidyanathan, K
Four commercially available spatial repellent devices were tested in a rice-land habitat near Stuttgart, AR, after semi-field level assessments had been made at the Center for Medical, Agricultural, and Veterinary Entomology, Agricultural Research Service, US Department of Agriculture in Gainesville, FL. OFF! Clip-On(metofluthrin), Mosquito Cognito (linalool), No-Pest Strip (dichlorvos), and ThermaCELL (d-cisltrans allethrin) were selected for this study from >20 candidate products. The units based on metofluthrin, linalool, or d-cisltrans allethrin significantly reduced captures of 1 or more of the mosquito species at surrogate human sites (unlit Centers for Disease Control and Prevention traps with CO2 and octenol). Among the mosquito species analyzed statistically (Anopheles quadrimaculatus, Culex erraticus, and Psorophora columbiae), there were significantly different responses (up to 84% reduction) to individual products, suggesting that combinations of certain spatial repellents might provide significantly greater protection. PMID:24772674
Dame, David A; Meisch, Max V; Lewis, Carolyn N; Kline, Daniel L; Clark, Gary G
Full Text Available Abstract There is currently renewed interest in assessing the feasibility of the sterile insect technique (SIT to control African malaria vectors in designated areas. The SIT relies on the sterilization of males before mass release, with sterilization currently being achieved through the use of ionizing radiation. This paper reviews previous work on radiation sterilization of Anopheles mosquitoes. In general, the pupal stage was irradiated due to ease of handling compared to the adult stage. The dose-response curve between the induced sterility and log (dose was shown to be sigmoid, and there was a marked species difference in radiation sensitivity. Mating competitiveness studies have generally been performed under laboratory conditions. The competitiveness of males irradiated at high doses was relatively poor, but with increasing ratios of sterile males, egg hatch could be lowered effectively. Males irradiated as pupae had a lower competitiveness compared to males irradiated as adults, but the use of partially-sterilizing doses has not been studied extensively. Methods to reduce somatic damage during the irradiation process as well as the use of other agents or techniques to induce sterility are discussed. It is concluded that the optimal radiation dose chosen for insects that are to be released during an SIT programme should ensure a balance between induced sterility of males and their field competitiveness, with competitiveness being determined under (semi- field conditions. Self-contained 60Co research irradiators remain the most practical irradiators but these are likely to be replaced in the future by a new generation of high output X ray irradiators.
Knols Bart GJ
The control of mosquitoes transmitting infectious diseases relies mainly on the use of chemical insecticides. However, resistance to most chemical insecticides threatens mosquito control programs. In this context, the spraying of toxins produced by the bacteria Bacillus thuringiensis subsp. israelensis (Bti) in larval habitats represents an alternative to chemical insecticides and is now widely used for mosquito control. Recent studies suggest that resistance of mosquitoes to Bti toxin may occur locally but mechanisms have not been characterized so far. In the present study, we investigated gene transcription level variations associated with Bti toxin resistance in the mosquito Aedes aegypti using a next-generation sequencing approach. More than 6 million short cDNA tags were sequenced from larvae of two strains sharing the same genetic background: a Bti toxins-resistant strain and a susceptible strain. These cDNA tags were mapped with a high coverage (308 reads per position in average) to more than 6000 genes of Ae. aegypti genome and used to quantify and compare the transcription level of these genes between the two mosquito strains. Among them, 86 genes were significantly differentially transcribed more than 4-fold in the Bti toxins resistant strain comparatively to the susceptible strain. These included gene families previously associated with Bti toxins resistance such as serine proteases, alkaline phosphatase and alpha-amylase. These results are discussed in regards of potential Bti toxins resistance mechanisms in mosquitoes. PMID:22115744
Paris, Margot; Melodelima, Christelle; Coissac, Eric; Tetreau, Guillaume; Reynaud, Stephane; David, Jean-Philippe; Despres, Laurence
Full Text Available Fish breeding is a very important activity ensuring availability of fingerlings for the stocking of ponds, pens, tanks and cages. The breeding habits of fishes in nature differ from specie to specie Different species of fish choose different places in the aquatic environment for breeding. Most species do not breed when in captivity due to a number of factors. In Nigeria, induced breeding of African mud catfish through injection of ova prim hormone or pituitary gland is the main practice. This article reviews the wild sources of fish seeds, some cultivable fishes. carp breeding, relationship between the endocrine system and gonad development, function of the Central Nervous System (CNS in propagation, influence of ecological conditions on gonad development, artificial propagation of common carp, natural induced spawning, salmon culture and an innovation in the sea to educate fish breeders, fish genetics and fish culturist in other to facilitate their productivity.
The NASA Ames Ecosystem Science and Technology Branch and the U.S. Army Medical Research Institute of Infectious Diseases are conducting research to detect Rift Valley fever (RVF) vector habitats in eastern Africa using active and passive remote-sensing. The normalized difference vegetation index (NDVI) calculated from Landsat TM and SPOT data is used to characterize the vegetation common to the Aedes mosquito. Relationships have been found between the highest NDVI and the 'dambo' habitat areas near Riuru, Kenya on both wet and dry data. High NDVI values, when combined with the vegetation classifications, are clearly related to the areas of vector habitats. SAR data have been proposed for use during the rainy season when optical systems are of minimal use and the short frequency and duration of the optimum RVF mosquito habitat conditions necessitate rapid evaluation of the vegetation/moisture conditions; only then can disease potential be stemmed and eradication efforts initiated.
Ambrosia, Vincent G.; Linthicum, K. G.; Bailey, C. L.; Sebesta, P.
Full Text Available Since mosquito immatures had been previously reported found in bamboo internodes in the Brazilian state of Santa Catarina, a study was conducted from January to March 2011 to evaluate the mosquito fauna associated with artificially drilled bamboos in eight localities in the eastern region of this state. Ninety-one mosquitoes of the following species were recorded: Aedes albopictus (Skuse, 1894 (1.1%, Culex soperi Antunes & Lane, 1937 (11.0%, Onirium personatum (Lutz, 1904 (6.6%, Sabethes aurescens (Lutz, 1905 (38.5%, Sa. identicus Dyar & Knab, 1907 (16.5%, Sa. intermedius Lutz, 1904 (3.3%, Sa. purpureus (Theobald, 1907 (1.1%, Trichoprosopon pallidiventer Lutz, 1905 (6.6%, Trichoprosopon soaresi Lane & Cerqueira, 1942 (2.2% and Wyeomyia limai Lane & Cerqueira, 1942 (24.2%. The finding of Ae. albopictus in perforated bamboos and the diversified mosquito fauna, whose biology is mostly poorly known, indicates the need of more detailed studies. Bamboo internodes constitute an important breeding place or mosquitoes of several species in the studied area. Sabethes intermedius and Culex soperi are reported for the first time in the state.
Gerson Azulim Müller
The requirement for efficient mosquito mass rearing technology has been one of the major obstacles preventing the large scale application of the Sterile Insect Technique against mosquitoes. At the Food and Agriculture Organization/International Atomic Energy Agency (FAO/ IAEA) Insect Pest Control Laboratories we developed a larval rearing unit based on the use of a stainless steel rack that operates 50 thermoformed ABS plastic trays and is expected to be able to successfully rear 140,000-175,000 Anopheles arabiensis (Patton) adult mosquitoes per rack. The mechanized rearing unit is simple to handle, maintains minimal water temperature variation and negligible water evaporation and allows normal larval development. The mosquito mass-rearing tray was designed to provide a large surface area of shallow water that would closely mimic natural breeding sites. The trays stack into a dedicated rack structure and filling and draining were easily performed. The close stacking of the trays in the rack and the possibility to tightly line up several racks makes this rearing unit a valid solution for maximal use of the space thus reducing construction, heating, and cooling costs. The low amount of labor required to operate the system also reduces labor costs that represent one of the main expenditures in any mass rearing facility operation. Preliminary experiments performed on Aedes albopictus (Skuse) also confirm the possibility of successfully extending the use of this technology to other mosquito species. Our larval rearing unit could enhance any mosquito control strategy in which large-scale releases of mosquitoes are needed to suppress or replace natural populations. PMID:22679867
Balestrino, F; Benedict, M Q; Gilles, J R L
Southeast Alaska provides non-breeding habitat for >300,000 sea ducks, however little is known about habitat features that may influence their distribution within this area. We used an autologistic regression model to examine relationships between 10 species of sea ducks that winter in southeast Alaska [harlequin duck (Histrionicus histrionicus), red breasted merganser (Mergus serrator), common merganser (Mergus merganser), bufflehead (Bucephala albeola), Barrow’s goldeneye (Bucephala is...
The emergence of insecticide-resistant mosquitoes strongly challenges the fight against mosquito-borne diseases, in particular malaria. In this paper, we formulate a system of nonlinear difference equations for malaria transmission cycle. Our model incorporates compartments for insecticide-resistant mosquitoes, where mutation is the only evolutionary force involved in the occurrence of resistant allele in the mosquito population. By deriving an epidemiological threshold, the global stability of the disease and the resistance-free fixed point is established for reduced recruitment rates of resistant mosquitoes. Furthermore, by employing numerical techniques, we showed that the mosquito-human transmission cycle of malaria and its prevalence could be impacted by mutation rate, the personal protection of hosts and the density of mosquitoes. Our results highlight that given a large mosquito population, the presence of even a small number of resistant mosquitoes to an insecticide could make the insecticide ineffective for malaria control. This suggests the need for effective insecticide management strategy, alternate mosquito control approaches, educating the public about personal protection and reduction of mosquito population in a given environment. PMID:24657875
Blayneh, Kbenesh W; Mohammed-Awel, Jemal
Full Text Available Mosquito repellants prevent mosquito bites and prevention of "man-mosquito contact" is a critical factor in transmission and spread of any disease through mosquitoes particularly in rural area. There has been a long standing 'bias' towards rural buyers. The rural markets are considered rigid in the nature but it is not the case in real sense. Marketing to rural buyers is not only a challenge to the marketers but to the manufacturers, communicators, national planners and economists as well. That is why it has been necessary to understand the various aspects of selected rural areas and consumption pattern for such a fast growing market i.e. mosquito repellants and rural buyers’ perception towards such urban products. The present paper aims to find out the factors influencing the purchase decisions of rural buyers for mosquito repellants and to study the perceptions of present and potential rural buyers' of selected mosquito repellant brands.
A study was conducted during the summer of 2009 (from July to September) to characterize mosquito communities among different habitats in five historically ditched tidal salt marshes and three adjacent wooded areas in the E.A. Vaughn Wetland Management Area on the Maryland Delmarva Peninsula, USA. Study marshes are characteristic of Atlantic coastal salt marshes that had undergone grid ditching from the 1930s to 1950s. In the autumn of 2008 (October and November) ditches were plugged near the...
Leisnham, Paul T.; Sarah Sandoval-Mohapatra
Urban malaria cases are becoming common in Africa as more people move into cities and industrialization proceeds. While many species of Anopheles mosquitoes vector malaria in rural areas, only a few are found within cities. The success of anthropophilic species in cities, such as members of the An. gambiae complex, may be explained by limitations on colonization by predator species in urban environments. Habitats that are temporal or structurally simple have lower predator survivorship in a v...
Carlson, John; Keating, Joseph; Mbogo, Charles M.; Kahindi, Samuel; Beier, John C.
Abstract Background Car tires are important habitats for mosquito development because of the high density populations they can harbor and their presence in urban settings. Water in experimental tires was treated with one of three insecticides or an untreated control. Aquatic invertebrates were sampled at weekly intervals. Eggs, larval and pupal samples were laboratory-reared to estimate seasonal fluctuations in Aedes aegypti and Ae. albopictus abundance....
Marina Carlos F; Bond J.; Muñoz José; Valle Javier; Chirino Nelva; Williams Trevor
A faunal survey of mosquitoes was conducted in 1988 and 1989 at Savanna Portage State Park in north-central Minnesota (Aitkin County). Adults were sampled by sweep net around collectors, aspirator in vegetation, and CO2 traps in the park. Larvae were taken with dipper from various larval habitats. A total of 32 species were detected, including 16 new records for Aitkin County, MN. Prior to this survey, Aedes decticus and Culiseta melanura were reported in Minnesota once previously. PMID:21033060
Crane, Diann M; Moon, Roger D
Control programs using conventional insecticides to target anthropogenic mosquito habitats are very expensive because these habitats are widespread, particularly in cities of most African countries. Additionally, there are serious environmental concerns regarding large-scale application of most conventional insecticides. Clearly there is a need for alternative methods that are more effective, less expensive, and environmentally friendly. One such method would be the application of preparation...
Full text: The plain of the Nestos River is a coastal area of 25,000 ha of agricultural land irrigated by the day-regulated waters of the Nestos River. Rice fields (600 individual parcels of 1,900 ha of total surface) represent the most important breeding sites during summer (five larvicide applications on average). Abandoned agricultural land (over 200 fields of 900 ha) receiving occasionally irrigation water constitutes the second most productive mosquito-breeding site (1-2 applications). Approximately 1-2% of the total surface of 6,500 ha of corn cultivation fields is poorly drained and thus about 100 ha produce at least one generation of mosquitoes during the summer. Along its 25 kilometers of seashore, the area of Nestos comprises the lagoons of Kavala (extensive aquaculture), and the last part of the delta of the Nestos River, 11,500 ha of protected wetlands under the Ramsar convention. About 2,000 ha of these wetlands harbours plants such as Arthr. fruticosum, Sal. europea, Ael. littoralis, Ju. maritimus, Sc. maritimus, representing highly productive mosquito breeding sites (1-2 generations during the summer). Ecological mapping involved 3,200 individual vegetation polygons organised in 311 different sampling stations. Larvae sampling protocol was followed on a weekly basis for the individual and/or groups of parcels in the agricultural and natural environment. All the above information was systematically monitored and transferred to an ArcView (8.3)-GIS (Geographical Information System) database for further exploitation. In addition, mosquito breeding sites were recorded in the urban environment: within 9 villages, 2,300 individual residences were monitored and 1,070 cesspools were recorded, out of which more than 50% were producing mosquitoes (1-2 applications). In total 8,500 ha were treated with larvicides by using temephos and diflubenzuron (agricultural land), Bti (natural environment) and MMF-Agnique (urban environment). 70% of the applications were made by air using a spraying helicopter (Hiller) and a specially modified ultra-light motorized (Delta type) equipped with GPS (Geographical Positioning System). During the five years of application of the project, 17 species of mosquitoes have been identified, the most important being Ochlerotatus caspius and Anopheles spp. (human bait and CO2 traps). Nuisance has been considerably reduced since the beginning of the operations, when 1,000 bites/hour were not unusual. Evaluation of the project was made twice through 200 questionnaires in year 2000 and 180 questionnaires in year 2004. Local community is fully supporting the project: 90% of the people are willing to participate financially for the continuation of the project. (author)
The mosquito gut represents an ecosystem that accommodates a complex, intimately associated microbiome. It is increasingly clear that the gut microbiome influences a wide variety of host traits, such as fitness and immunity. Understanding the microbial community structure and its dynamics across mosquito life is a prerequisite for comprehending the symbiotic relationship between the mosquito and its gut microbial residents. Here we characterized gut bacterial communities across larvae, pupae and adults of Anopheles gambiae reared in semi-natural habitats in Kenya by pyrosequencing bacterial 16S rRNA fragments. Immatures and adults showed distinctive gut community structures. Photosynthetic Cyanobacteria were predominant in the larval and pupal guts while Proteobacteria and Bacteroidetes dominated the adult guts, with core taxa of Enterobacteriaceae and Flavobacteriaceae. At the adult stage, diet regime (sugar meal and blood meal) significantly affects the microbial structure. Intriguingly, blood meals drastically reduced the community diversity and favored enteric bacteria. Comparative genomic analysis revealed that the enriched enteric bacteria possess large genetic redox capacity of coping with oxidative and nitrosative stresses that are associated with the catabolism of blood meal, suggesting a beneficial role in maintaining gut redox homeostasis. Interestingly, gut community structure was similar in the adult stage between the field and laboratory mosquitoes, indicating that mosquito gut is a selective eco-environment for its microbiome. This comprehensive gut metatgenomic profile suggests a concerted symbiotic genetic association between gut inhabitants and host. PMID:21957459
Wang, Ying; Gilbreath, Thomas M; Kukutla, Phanidhar; Yan, Guiyun; Xu, Jiannong
This is the fourth in a series of lessons specifically designed to instruct individuals without any formal training in genetics or statistics about the science of corn breeding. Individuals with formal training in genetics or statistics but without any training in plant breeding also may benefit from taking these lessons.
An improved knowledge of mosquito life history could strengthen malaria vector control efforts that primarily focus on killing mosquitoes indoors using insecticide treated nets and indoor residual spraying. Natural sugar sources, usually floral nectars of plants, are a primary energy resource for adult mosquitoes but their role in regulating the dynamics of mosquito populations is unclear. To determine how the sugar availability impacts Anopheles sergentii populations, mark-release-recapture studies were conducted in two oases in Israel with either absence or presence of the local primary sugar source, flowering Acacia raddiana trees. Compared with population estimates from the sugar-rich oasis, An. sergentii in the sugar-poor oasis showed smaller population size (37,494 vs. 85,595), lower survival rates (0.72 vs. 0.93), and prolonged gonotrophic cycles (3.33 vs. 2.36 days). The estimated number of females older than the extrinsic incubation period of malaria (10 days) in the sugar rich site was 4 times greater than in the sugar poor site. Sugar feeding detected in mosquito guts in the sugar-rich site was significantly higher (73%) than in the sugar-poor site (48%). In contrast, plant tissue feeding (poor quality sugar source) in the sugar-rich habitat was much less (0.3%) than in the sugar-poor site (30%). More important, the estimated vectorial capacity, a standard measure of malaria transmission potential, was more than 250-fold higher in the sugar-rich oasis than that in the sugar-poor site. Our results convincingly show that the availability of sugar sources in the local environment is a major determinant regulating the dynamics of mosquito populations and their vector potential, suggesting that control interventions targeting sugar-feeding mosquitoes pose a promising tactic for combating transmission of malaria parasites and other pathogens. PMID:21283732
Gu, Weidong; Müller, Günter; Schlein, Yosef; Novak, Robert J; Beier, John C
This research evaluates the extent to which use of environmental data acquired from field and satellite surveys enhances predictions of urban mosquito counts. Mosquito larval habitats were sampled, and multispectral thermal imager (MTI) satellite data in the visible spectrum at 5-m resolution were acquired for Kisumu and Malindi, Kenya, during February and March 2001. All entomological parameters were collected from January to May 2001, June to August 2002, and June to August 2003. In a Poiss...
Jacob, Benjamin G.; Arheart, Kristopher L.; Griffith, Daniel A.; Mbogo, Charles M.; Githeko, Andrew K.; Regens, James L.; Githure, John I.; Novak, Robert; Beier, John C.
The terms of reference for ITER provide for incorporation of a tritium breeding blanket with a breeding ratio as close to unity as practical. A breeding blanket is required to assure an adequate supply of tritium to meet the program objectives. Based on specified design criteria, a ceramic breeder concept with water coolant and an austenitic steel structure has been selected as the first option and lithium-lead blanket concept has been chosen as an alternate option. The first wall, blanket, and shield are integrated into a single unit with separate cooling systems. The design makes extensive use of beryllium to enhance the tritium breeding ratio. The design goals with a tritium breeding ratio of 0.8--0.9 have been achieved and the R ampersand D requirements to qualify the design have been identified. 4 refs., 8 figs., 2 tabs
The terms of reference for ITER provide for incorporation of a tritium breeding blanket with a breeding ratio as close to unity as practical. A breeding blanket is required to assure an adequate supply of tritium to meet the program objectives. Based on specified design criteria, a ceramic breeder concept with water coolant and an austenitic steel structure has been selected as the first option and lithium-lead blanket concept has been chosen as an alternate option. The first wall, blanket, and shield are integrated into a single unit with separate cooling systems. The design makes extensive use of beryllium to enhance the tritium breeding ratio. The design goals with a tritium breeding ratio of 0.8--0.9 have been achieved and the R D requirements to qualify the design have been identified. 4 refs., 8 figs., 2 tabs.
Smith, D.; Billone, M.; Gohar, Y. (Argonne National Lab., IL (USA)); Baker, C. (Oak Ridge National Lab., TN (USA)); Mori, S.; Kuroda, T.; Maki, K.; Takatsu, H.; Yoshida, H. (Japan Atomic Energy Research Inst., Tokyo (Japan)); Raffray, A. (California Univ., Los Angeles, CA (USA)); Sviatoslavsky, I. (Wisconsin Univ., Madison, WI (USA)); Simbolotti, G. (ENEA, Frascati (Italy). Centro Ricerche Energia); Dae
Background The water level of Lake Victoria has fallen more than 1.5 m since 1998, revealing a narrow strip of land along the shore. This study determined whether the recent drop in the water level has created additional breeding grounds for malaria vectors. Methods The recent and past shorelines were estimated using landmarks and a satellite image. The locations of breeding habitats were recorded using a GPS unit during the high and low lake water periods. GIS was used to determine whether the breeding habitats were located on newly emerged land between the new and old shorelines. Results Over half of the breeding habitats existed on newly emerged land. Fewer habitats for the Anopheles gambiae complex were found during the low water level period compared to the high water period. However, more habitats for Anopheles funestus were found during the high water level period, and they were all located on the newly emerged land. Conclusion The recent reduction in water level of Lake Victoria has increased the amount of available habitat for A. funestus. The results suggest that the water drop has substantially affected the population of this malaria vector in the Lake Victoria basin, particularly because the lake has a long shoreline that may harbour many new breeding habitats.
Minakawa, Noboru; Sonye, Gorge; Dida, Gabriel O; Futami, Kyoko; Kaneko, Satoshi
Full Text Available Abstract Background The water level of Lake Victoria has fallen more than 1.5 m since 1998, revealing a narrow strip of land along the shore. This study determined whether the recent drop in the water level has created additional breeding grounds for malaria vectors. Methods The recent and past shorelines were estimated using landmarks and a satellite image. The locations of breeding habitats were recorded using a GPS unit during the high and low lake water periods. GIS was used to determine whether the breeding habitats were located on newly emerged land between the new and old shorelines. Results Over half of the breeding habitats existed on newly emerged land. Fewer habitats for the Anopheles gambiae complex were found during the low water level period compared to the high water period. However, more habitats for Anopheles funestus were found during the high water level period, and they were all located on the newly emerged land. Conclusion The recent reduction in water level of Lake Victoria has increased the amount of available habitat for A. funestus. The results suggest that the water drop has substantially affected the population of this malaria vector in the Lake Victoria basin, particularly because the lake has a long shoreline that may harbour many new breeding habitats.
Full Text Available The comparative analysis of hooded crow breeding ecology was performed for Zhitomir region in 2010-2011 in terms of rural and urban distinctions. Height of trees, tree species diversity in breeding biotopes, nest size, and breeding success of hooded crows were considered for agricultural and urban landscapes. Definite patterns of breeding ecology were estimated for urban and rural populations of hooded crows. On average, the breeding density of hooded crows was 7-8 individuals/km2in Zhitomir region.Positive correlation was found between the breeding density of hooded crows and degree of transformation and urbanization of landscape of Zhytomyr region. The main breeding habitats of hooded crows in the Zhitomir region were the wetland sites. Communities of urban birds were characterized by earlier terms of nest building, more higher position of nests in the trees and high diversity of tree breeding habitats. In urbanized landscape we determined high proportion of large (6 eggs and small clutches of hooded crow (3 eggs. On average the breeding success of crows in Zhytomyr region is 51.1%. We suggested that the main factor was high level of elimination of embryos and chicks of hooded crow. In urbanized landscapes the breeding success (50% is somewhat higher than that in rural areas (43.5%. This can be explained by specific features of ecological niches - in cities the bird communities have few natural predators that kill chicks and destroy clutches, and potentially have more available food resources.
Many vertebrates breed in cooperative groups in which more than two members provide care for young. Studies of cooperative breeding behavior within species have long highlighted the importance of environmental factors in mediating the paradox of why some such individuals delay independent breeding to help raise the offspring of others. In contrast, studies involving comparisons among species have not shown a similarly clear evolutionary-scale relationship between the interspecific incidence of cooperative breeding and any environmental factors. Here, we use a phylogenetically controlled comparative analysis of a complete, socially diverse group of birds-45 species of African starlings-to show that cooperative breeding is positively associated with living in semiarid savanna habitats and with temporal variability in rainfall. Savanna habitats are not only highly seasonal, but also temporally variable and unpredictable, and this temporal variability directly influences individual reproductive decisions in starlings and helps explain interspecific patterns of sociality. Cooperative breeding is likely to be adaptive in temporally variable environments because it allows for both reproduction in harsh years and sustained breeding during benign years. This "temporal variability" hypothesis might help explain the phylogenetic and geographic concentrations of cooperatively breeding vertebrates in savanna-like habitats and other temporally variable environments worldwide. PMID:17702577
Rubenstein, Dustin R; Lovette, Irby J
This paper develops an optimal control framework for an ordinary differential equation model to investigate the introduction of sterile mosquitoes to reduce the incidence of mosquito-borne diseases. Existence of a solution given an optimal strategy and the optimal control is determined in association with the negative effects of the disease on the population while minimizing the cost due to this control mechanism. Numerical simulations have shown the importance of effects of the bounds on the release of sterile mosquitoes and the bounds on the likelihood of egg maturation. The optimal strategy is to maximize the use of habitat modification or insecticide. A combination of techniques leads to a more rapid elimination of the wild mosquito population. PMID:23743207
Renee Fister, K; McCarthy, Maeve L; Oppenheimer, Seth F; Collins, Craig
Ochlerotatus (Finlaya) japonicus japonicus (Theobald; =Aedes japonicus; see Reinert 2000) (Diptera: Culicidae), is an introduced Asian mosquito species first detected in the northeastern United States in 1998. Since its initial discovery, this species has spread to many neighboring states and Canada. It was first identified in North Carolina, South Carolina, and Georgia in 2003. Larval surveys were conducted during 2005 and 2006 in the Southern Appalachians, U.S.A., on a variety of natural and artificial containers to determine extent of Oc.japonicus establishment and larval habitat requirements. Detritus amounts were measured in each container habitat, and co-occurring larval mosquito species were examined as indicators of potential interspecific competition. Data reveal that Oc. japonicus was the most abundant container-inhabiting mosquito species in this survey. It exhibits flexibility in its use of container oviposition habitats, it can persist in a wide range of conditions, and it co-occurs with a wide range of larval mosquito species. Its rapid and successful establishment warrants continued monitoring, because its potential role as a nuisance species or arbovirus vector remains unknown. PMID:18047192
Bevins, Sarah N
Full Text Available A study of the ecology of drainage - breeding mosquito vectors was conducted in the three urban centers (Owerri, Orlu and Okigwe of Imo State, Nigeria. Four drainage sites located around markets, residential, stream and hotel premises were selected in each urban centre. Dipping method of sampling was employed and a total of 8,820 mosquitoes comprising eight species namely; Aedes aegypti, Aedes vittatus, Culex quinquefasciatus, Culex tigripes, Culex horridus, Culex cinereus, Culex annuliorus and Anopheles gambiae were encountered; in Owerri and Orlu with Cx. cinereus being completely absent in Okigwe. Cx. quinquefasciatus was predominantly present in all drainage sites with the highest occurrence of 4,474(50.74% followed by Aedes aegypti 1814 (20.57%, An .gambiae 945(10.71%, Cx. tigripes 484 (5.48% Ae. vittatus 420 (4.76%, Cx. horridus 264 (02.99%, Cx. cinereus 261 (2.96%, Cx. annuliorus 159 (1.88%. Of all sites sampled, market drainages had the highest abundance of mosquitoes which was significantly higher than (ANOVA, P? 0.05 those found in the residential, streams and hotel premises. Residential drainages recorded the second highest density followed by stream/vegetation drainages and hotel drainages which had the least. The abundance and distribution of mosquitoes in Owerri (130.06 the State Capital was significantly higher (ANOVA, P? 0.05 than those for Orlu (93.44 and Okigwe (52.13. The mosquito species identified in this study are of public health importance and there is an urgent need to desilt and clean up these drainages for free flow of water. This will not only rid these species of breeding sites but also free the State of the diseases associated with these organisms.
Ifeyinwa Celestina MGBEMENA
The achievements made in mutation breeding in Japan over the past 40 years are outlined from the viewpoint of practical breeding. Fifty-four varieties of 23 crops were obtained by direct use of induced mutants. These include 12 cereal mutant varieties, five food legumes, nine industrial crops, seven vegetables and 18 ornamentals. Ten varieties were obtained by national breeding institutes, 14 by prefectural stations and 30 by universities or private firms. The varieties produced by the national breeding programme were registered and released with Norin numbers. In most cases, ionizing radiation was used. Forty additional mutant varieties were developed through cross-breeding using induced mutants as the gene sources. Of the 33 rice varieties in this category, 21, including six national varieties, resulted from crosses involving Reimei, a semi-dwarf mutant variety. Another semi-dwarf mutant parent was used to breed two more national varieties. Three early heading mutants were also integrated into cross-breeding programmes and produced three national and two prefectural varieties. A large grain mutant produced three varieties for sake brewing. A new recessive resistant mutant allele to the soil borne virus (BaYMV) was induced in barley. One variety was bred using this mutant as a parent. Another promising disease resistant clone was induced by chronic irradiation in a gamma field in the leading Japanese pear variety Nijisseiki, which is susceptible to black spot disease caused by Alternaria alternata (Fr.) Keissler. This mutant clone maintained all the superior qualities of the original variety. The significant role of the Institute of Radiation Breeding as a core in mutation breeding is mentioned briefly. (author). 10 refs, 2 figs, 6 tabs
Full Text Available The effect of permethrin-treated Africa University (AU mosquito blankets on susceptible female Anopheles gambiae sensu lato mosquitoes was studied under laboratory conditions at Africa University Campus in Mutare, Zimbabwe. Wash resistance (ability to retain an effective dose that kills ?80% of mosquitoes after a number of washes and repellence (ability to prevent ?80% of mosquito bites properties were studied. The AU blankets were wash resistant when 100% mortality was recorded up to 20 washes, declining to 90% after 25 washes. Untreated AU blankets did not cause any mortality on mosquitoes. However, mosquito repellence was 96%, 94%, 97.9%, 87%, 85% and 80.7% for treated AU blankets washed 0, 5, 10, 15, 20 and 25 times, respectively. Mosquito repellence was consistently above 80% from 0-25 washes. In conclusion, AU blankets washed 25 times were effective in repelling and killing An. gambiae sl mosquitoes under laboratory conditions.
The prevalence of protozoan, Ascogregarina sp. had been determined in the container breeding mosquitoes, Aedes albopictus. Since, the cyst of Ascogregarina might play role in the maintenance of the Chik virus during silent period, the presence of Ascogregarina has gained importance in recent days. The prevalence was found to be 71.62. PMID:22471176
Muniaraj, M; Rajendran, R; Arunachalam, N; Paramasivan, R; Samuel, P Philip
Spatial evaluation of larvae of Culicidae (Diptera) from different breeding sites: application of a geospatial method and implications for vector control / Avaliação espacial de formas larvais de Culicidae (Diptera) em diferentes criadouros: aplicação de um método geoespacial e implicações para o controle de vetores
Full Text Available SciELO Brazil | Language: English Abstract in portuguese Avaliação espacial de formas larvais de Culicidae (Diptera) em diferentes criadouros: aplicação de um método geoespacial e implicações para o controle de vetores. Este estudo investiga a distribuição espacial da fauna urbana e de Culicidae e informa o monitoramento entomológico de espécies que usam [...] recipientes artificiais como habitat larval. Coletas de larvas de mosquitos foram realizadas no município paulista de Santa Bárbara d' Oeste entre os anos de 2004 e 2006, durante visitas casa-a-casa. Um total de 1.891 amostras foi considerado, com nove espécies diferentes coletadas. A distribuição das espécies foi avaliada através do método de krigagem estatística extrapolando as divisões administrativas do município. O método de coleta adotado no presente estudo está de acordo com os métodos sugeridos aos serviços de saúde municipais pelo Ministério da Saúde e pode, portanto, ser adotado pelas autoridades públicas de saúde no controle da doença e delimitação das áreas de risco. Além disso, este tipo de levantamento e análise pode ser empregado como vigilância entomológica de espécies de mosquitos vetores que usam recipientes artificiais como habitat larval em áreas urbanas. Abstract in english Spatial evaluation of Culicidae (Diptera) larvae from different breeding sites: application of a geospatial method and implications for vector control. This study investigates the spatial distribution of urban Culicidae and informs entomological monitoring of species that use artificial containers a [...] s larval habitats. Collections of mosquito larvae were conducted in the São Paulo State municipality of Santa Bárbara d' Oeste between 2004 and 2006 during house-to-house visits. A total of 1,891 samples and nine different species were sampled. Species distribution was assessed using the kriging statistical method by extrapolating municipal administrative divisions. The sampling method followed the norms of the municipal health services of the Ministry of Health and can thus be adopted by public health authorities in disease control and delimitation of risk areas. Moreover, this type of survey and analysis can be employed for entomological surveillance of urban vectors that use artificial containers as larval habitat.
Piovezan, Rafael; Azevedo, Thiago Salomão de; Von Zuben, Cláudio José.
Spatial evaluation of larvae of Culicidae (Diptera from different breeding sites: application of a geospatial method and implications for vector control Avaliação espacial de formas larvais de Culicidae (Diptera em diferentes criadouros: aplicação de um método geoespacial e implicações para o controle de vetores
Full Text Available Spatial evaluation of Culicidae (Diptera larvae from different breeding sites: application of a geospatial method and implications for vector control. This study investigates the spatial distribution of urban Culicidae and informs entomological monitoring of species that use artificial containers as larval habitats. Collections of mosquito larvae were conducted in the São Paulo State municipality of Santa Bárbara d' Oeste between 2004 and 2006 during house-to-house visits. A total of 1,891 samples and nine different species were sampled. Species distribution was assessed using the kriging statistical method by extrapolating municipal administrative divisions. The sampling method followed the norms of the municipal health services of the Ministry of Health and can thus be adopted by public health authorities in disease control and delimitation of risk areas. Moreover, this type of survey and analysis can be employed for entomological surveillance of urban vectors that use artificial containers as larval habitat.Avaliação espacial de formas larvais de Culicidae (Diptera em diferentes criadouros: aplicação de um método geoespacial e implicações para o controle de vetores. Este estudo investiga a distribuição espacial da fauna urbana e de Culicidae e informa o monitoramento entomológico de espécies que usam recipientes artificiais como habitat larval. Coletas de larvas de mosquitos foram realizadas no município paulista de Santa Bárbara d' Oeste entre os anos de 2004 e 2006, durante visitas casa-a-casa. Um total de 1.891 amostras foi considerado, com nove espécies diferentes coletadas. A distribuição das espécies foi avaliada através do método de krigagem estatística extrapolando as divisões administrativas do município. O método de coleta adotado no presente estudo está de acordo com os métodos sugeridos aos serviços de saúde municipais pelo Ministério da Saúde e pode, portanto, ser adotado pelas autoridades públicas de saúde no controle da doença e delimitação das áreas de risco. Além disso, este tipo de levantamento e análise pode ser empregado como vigilância entomológica de espécies de mosquitos vetores que usam recipientes artificiais como habitat larval em áreas urbanas.
Objective To investigate what kind of mosquito sample is necessary for the determination of insecticide susceptibility in malaria vectors. Methods Larvae and pupae of Anopheles gambiae s.l. (An. gambiae) mosquitoes were collected from the breeding sites in Littoral and Oueme departments. The Centers for Disease Control and Prevention (CDC) susceptibility tests were conducted on unfed male and female mosquitoes aged 2-5 days old. CDC susceptibility tests were also conducted on unfed, blood fed and gravid female mosquitoes aged 2-5 days old. These susceptibility tests were also conducted on unfed and blood fed female mosquitoes aged 2-5 days old and 20 days old. CDC biochemical assay using synergist was also carried out to detect any increase in the activity of enzyme typically involved in insecticide metabolism. Results Female An. gambiae Ladji and Sekandji populations were more susceptible than the males when they were unfed and aged 2-5 days old. The mortality rates of blood fed female An. gambiae Ladji and Sekandji populations aged 2-5 days old were lower than those obtained when females were unfed. In addition, the mortality rates of gravid female An. gambiae Ladji and Sekandji populations aged 2-5 days old were lower than those obtained when they were unfed. The mortality rate obtained when female An. gambiae Sekandji populations were unfed and aged 20 days old was higher than the one obtained when these populations were unfed and aged 2-5 days old. The results obtained after effects of synergist penicillin in beeswax on F1 progeny of An. gambiae Ladji populations resistant to permethrin showed that mono-oxygenases were involved in permethrin resistant F1 progeny from Ladji. Conclusions The resistance is a hereditary and dynamic phenomenon which can be due to metabolic mechanisms like overproduction of detoxifying enzymes activity. Many factors influence vector susceptibility to insecticide. Among these factors, there are mosquito sex, mosquito age, its physiological status. Therefore, it is useful to respect the World Health Organization criteria in the assessment of insecticide susceptibility tests in malaria vectors. Otherwise, susceptibility testing is conducted using unfed female mosquitoes aged 3-5 days old. Tests should also be carried out at (25±2) °C and (80±10)% relative humidity.
Aizoun, Nazaire; Aikpon, Rock; Azondekon, Roseric; Asidi, Alex; Akogbeto, Martin
The effect of permethrin-treated Africa University (AU) mosquito blankets on susceptible female Anopheles gambiae sensu lato mosquitoes was studied under laboratory conditions at Africa University Campus in Mutare, Zimbabwe. Wash resistance (ability to retain an effective dose that kills ?80% of mosquitoes after a number of washes) and repellence (ability to prevent ?80% of mosquito bites) properties were studied. The AU blankets were wash resistant when 100% mortality was reco...
Lukwa, N.; Makuwaza, A.; Chiwade, T.; Mutambu, S. L.; Zimba, M.; Munosiyei, P.
Larval collections in Nebraska during 2000 established 2 new state distribution records for Ochlerotatus epactius and Anopheles perplexens and confirmed the presence of Culiseta melanura, bringing the total number of mosquito species reported from Nebraska to 50. Fifteen new county records for 10 species are noted, including the 1st report of Aedes albopictus from Lancaster County, marking its westernmost collection in Nebraska to date. PMID:11804465
Moore, J P
Mosquitoes act as a vector for most of the life threatening diseases like malaria, yellow fever, dengue fever, chikungunya ferver, filariasis, encephalitis, West Nile Virus infection, etc. Under the Integrated Mosquito Management (IMM), emphasis was given on the application of alternative strategies in mosquito control. The continuous application of synthetic insecticides causes development of resistance in vector species, biological magnification of toxic substances through the food chain an...
Ghosh, Anupam; Chowdhury, Nandita; Chandra, Goutam
When animals cluster their territories within larger patches of seemingly appropriate habitat it could mean that they have additional, finer scale habitat requirements or that non-habitat cues play a role in their selection decisions. Sagebrush Brewer’s Sparrows (Spizella breweri breweri) cluster their territories throughout their breeding range. I examined territory-scale selection by the species using two approaches: observation of individual selection for vegetation characteristics, and ...
We present a breeding protocol that distills pure copies of any stabilizer state from noisy copies and a pool of predistilled pure copies of the same state, by means of local Clifford operations, Pauli measurements and classical communication.
Hostens, E; Dehaene, J; Dehaene, Jeroen; Hostens, Erik; Moor, Bart De
Full Text Available Fungal diseases in insects are common and widespread and can decimate their populations in spectacular epizootics. Virtually all insect orders are susceptible to fungal diseases, including Dipterans. Fungal pathogens such as Lagenidium, Coelomomyces and Culicinomyces are known to affect mosquito populations, and have been studied extensively. There are, however, many other fungi that infect and kill mosquitoes at the larval and/or adult stage. The discovery, in 1977, of the selective mosquito-pathogenic bacterium Bacillus thuringiensis Berliner israelensis (Bti curtailed widespread interest in the search for other suitable biological control agents. In recent years interest in mosquito-killing fungi is reviving, mainly due to continuous and increasing levels of insecticide resistance and increasing global risk of mosquito-borne diseases. This review presents an update of published data on mosquito-pathogenic fungi and mosquito-pathogen interactions, covering 13 different fungal genera. Notwithstanding the potential of many fungi as mosquito control agents, only a handful have been commercialized and are marketed for use in abatement programs. We argue that entomopathogenic fungi, both new and existing ones with renewed/improved efficacies may contribute to an expansion of the limited arsenal of effective mosquito control tools, and that they may contribute in a significant and sustainable manner to the control of vector-borne diseases such as malaria, dengue and filariasis.
Full Text Available Sterile Insect Technique (SIT has been applied successfully in some agricultural pest control programs in the past, but in many cases, success has not been sustainable in the long run. Various attempts have been made to duplicate this limited success SIT application in agriculture to other areas of applications, particularly in vector control. For example, a recent mosquito control program has been initiated in Malaysia to eliminate dengue-mosquitoes Aedes aegypti by releasing large amount of genetically modified GM male mosquitoes into the field to outcompete the wild male mosquitoes. Field experimental data that has been made available in the literature is limited, rendering it difficult to make independent assessment on its short-term efficacy and long-term sustainability of this GM control strategy. This paper presents a preliminary assessment of the effectiveness of GM mosquito in controlling dengue mosquito population by means of model simulations via DEER (Dengue Encephalitis Eradication Routines. Preliminary results indicate negative conclusion regarding the effectiveness of GM mosquitoes in controlling wild A. aegypti population over the long-term. Essentially, significant reduction of wild mosquito population is possible only if large over-flooding ratios are applied. Further, repeated releases must be maintained over an infinite time horizon to continue to sustain low population of mosquitoes. Major difficulty remains to be resolved. In particular, in-depth costbenefit analysis on this control program is essential to ensure long-term institutional and social support.
Teh Su Yean
Abstract Background Physical objects like vegetation can influence oviposition by mosquitoes on soil or water substrates. Anopheles gambiae s. l. is generally thought to utilize puddles over bare soil as its prime larval habitat and to avoid standing water populated with vegetation. In Kisian, Kenya near Kisumu, water often pools in grassy drainage areas both during and after periods of infrequent rains, when typical puddle habitats become scarce because of drying. T...
Huang Juan; Walker Edward D; Otienoburu Philip E; Amimo Fred; Vulule John; Miller James R
A large proportion of mosquito larval habitats in urban and rural communities in sub-Saharan Africa are man-made. Therefore, community-based larval source management (LSM) could make a significant contribution to malaria control in an integrated vector management approach. Here we implemented an exploratory study to assess malaria prevalence and people's knowledge, attitudes and practices on malaria transmission, its control and the importance of man-made aquatic habitats for the development ...
Background: Limitations in the ability of organisms to tolerate environmental stressors affect their fundamental ecological niche and constrain their distribution to specific habitats. Evolution of tolerance, therefore, can engender ecological niche dynamics. Forest populations of the afro-tropical malaria mosquito Anopheles gambiae have been shown to adapt to historically unsuitable larval habitats polluted with decaying organic matter that are found in densely populated urban agglomerates o...
Tene Fossog, Billy; Antonio-nkondjio, Christophe; Kengne, Pierre; Njiokou, Flobert; Besansky, Nora J.; Costantini, Carlo
Full Text Available Abstract Background Continuous land cover modification is an important part of spatial epidemiology because it can help identify environmental factors and Culex mosquitoes associated with arbovirus transmission and thus guide control intervention. The aim of this study was to determine whether remotely sensed data could be used to identify rice-related Culex quinquefasciatus breeding habitats in three rice-villages within the Mwea Rice Scheme, Kenya. We examined whether a land use land cover (LULC classification based on two scenes, IKONOS at 4 m and Landsat Thematic Mapper at 30 m could be used to map different land uses and rice planted at different times (cohorts, and to infer which LULC change were correlated to high density Cx. quinquefasciatus aquatic habitats. We performed a maximum likelihood unsupervised classification in Erdas Imagine V8.7® and generated three land cover classifications, rice field, fallow and built environment. Differentially corrected global positioning systems (DGPS ground coordinates of Cx. quinquefasciatus aquatic habitats were overlaid onto the LULC maps generated in ArcInfo 9.1®. Grid cells were stratified by levels of irrigation (well-irrigated and poorly-irrigated and varied according to size of the paddy. Results Total LULC change between 1988–2005 was 42.1 % in Kangichiri, 52.8 % in Kiuria and and 50.6 % Rurumi. The most frequent LULC changes was rice field to fallow and fallow to rice field. The proportion of aquatic habitats positive for Culex larvae in LULC change sites was 77.5% in Kangichiri, 72.9% in Kiuria and 73.7% in Rurumi. Poorly – irrigated grid cells displayed 63.3% of aquatic habitats among all LULC change sites. Conclusion We demonstrate that optical remote sensing can identify rice cultivation LULC sites associated with high Culex oviposition. We argue that the regions of higher Culex abundance based on oviposition surveillance sites reflect underlying differences in abundance of larval habitats which is where limited control resources could be concentrated to reduce vector larval abundance.
ABSTRACT. Fifty-three mosquito species belonging to 20 subgenera and 18 genera--Aedes, Anopheles, Armigeres, Culex, Downsiomyia, Finlaya, Heizmannia, Kenknightia, Lorrainea, Lutzia, Ochlerotatus, Orthopodomyia, Rhinoskusea, Stegomyia, Toxorhynchites, Tripteroides, Uranotaenia, and Verrallina--were recorded in the mangroves of Andaman and Nicobar Islands, India, in collections made during May and June 2001. Larvae of 43 species were collected from different mangrove habitats. Together with collections made in nonmangrove areas, 83 species in 22 subgenera and 20 genera in total were recorded of which 33 species are new records for the Andaman and Nicobar Islands. Rhinoskusea wardi, Fl. flavipennis, and Ve. consonensis are 3 new country records for India. Collections included topotype specimens of St. seampi. Together with species known from earlier records, the mosquito fauna of Andaman and Nicobar Islands is updated to 107 species in 23 subgenera and 24 genera. PMID:17067033
Rajavel, A R; Natarajan, R
Full Text Available Abstract Background Anopheles plumbeus has been recognized as a minor vector for human malaria in Europe since the beginning of the 20th century. In recent years this tree hole breeding mosquito species appears to have exploited novel breeding sites, including large and organically rich man-made containers, with consequently larger mosquito populations in close vicinity to humans. This lead to investigate whether current populations of An. plumbeus would be able to efficiently transmit Plasmodium falciparum, the parasite responsible for the most deadly form of malaria. Methods Anopheles plumbeus immatures were collected from a liquid manure pit in Switzerland and transferred as adults to the CEPIA (Institut Pasteur, France where they were fed on P. falciparum gametocytes produced in vitro. Anopheles gambiae mosquitoes served as controls. Development of P. falciparum in both mosquito species was followed by microscopical detection of oocysts on mosquito midguts and by sporozoite detection in the head/thorax by PCR and microscopy. Results A total of 293 wild An. plumbeus females from four independent collections successfully fed through a membrane on blood containing P. falciparum gametocytes. Oocysts were observed in mosquito midguts and P. falciparum DNA was detected in head-thorax samples in all four experiments, demonstrating, on a large mosquito sample, that An. plumbeus is indeed receptive to P. falciparum NF54 and able to produce sporozoites. Importantly, the proportion of sporozoites-infected An. plumbeus was almost similar to that of An. gambiae (31 to 88% An. plumbeus versus 67 to 97% An. gambiae. However, the number of sporozoites produced was significantly lower in infected An. plumbeus. Conclusion The results show that a sample of field-caught An. plumbeus has a moderate to high receptivity towards P. falciparum. Considering the increased mobility of humans between Europe and malaria endemic countries and changes in environment and climate, these data strongly suggest that An. plumbeus could act as a vector for malaria and thus significantly contribute to increasing the malaria transmission risk in Central-Western Europe. In locations showing high vulnerability to the presence of gametocyte carriers, the risk of transmission of malaria by An. plumbeus should be considered.
We developed a habitat model to predict cerulean warbler (Dendroica cerulea) habitat availability in the Cumberland Mountains of eastern Tennessee. We used 7 remotely sensed vegetation and topographic landform explanatory variables and known locations of territorial male cerulean warblers mapped in 2003 as the response variable to develop a Mahalanobis distance statistic model of potential habitat. We evaluated the accuracy of the model based on field surveys for ceruleans during the 2004 breeding season. The model performed well with an 80% correct classification of cerulean presence based on the validation data, although prediction of absence was only 54% correct. We extrapolated from potential habitat to cerulean abundance based on density estimates from territory mapping on 8 20-ha plots in 2005. Over the 200,000-ha study area, we estimated there were 80,584 ha of potential habitat, capable of supporting about 36,500 breeding pairs. We applied the model to the 21,609-ha state-owned Royal Blue Wildlife Management Area to evaluate the potential effects of coal surface mining as one example of a potential conflict between land use and cerulean warbler conservation. Our models suggest coal surface mining could remove 2,954 ha of cerulean habitat on Royal Blue Wildlife Management Area and could displace 2,540 breeding pairs (23% of the Royal Blue population). A comprehensive conservation strategy is needed to address potential and realized habitat loss and degradation on the breeding grounds, during migration, and on the wintering grounds.
Buehler, D.A.; Welton, M.J.; Beachy, T.A. [University of Tennessee, Knoxville, TN (United States). Dept. of Forestry Wildlife & Fisheries
Full Text Available Two genera of Microsporidia were found infecting mosquito larvae in three localities on the Pacific coast of Choco. Vavraia sp. (Microsporida: Pleistophoridae was found in larvae of Wyeomyia circumcincta, W. simmsi and Anopheles albimanus collected from plants of the Bromeliacea family in Arusí y Joví. Amblyospora sp. (Microsporida: Amblyosporidae was found parasitizingAedes angustivittatuslarvae COllectedfrom a terrestrial breeding pond in the locality of Nuqur. Morphology of the spores of the two parasites under light microscopy is described, as well as preliminary data on host range when exposed to laboratory rearad Aedes aegypti, Culex quinquefasciatus and Anopheles albimanus. Their rola in mosquito control is discussed.Se reportan dos géneros de microsporidia que parasitan larvas de mosquitos en criaderos naturales de tres localidades en la costa Pacffica Chocoana. Vavraia sp. (Microsporida: Pleistophoridae parásita larvas de Wyeomyia circumcincta, de Wyeomya simmsi y de Anopheles neivai, recolectadas en las rosetas de especies de la familia Bromeliaceae en las localidades de Arusí y Joví. Amblyospora sp. (Microsporida: Amblyosporidae parásita larvas deAedes angustivittatusde criaderos terrestres semipermanentes en la localidad de Nuquí. Se describe la morfología de estos dos microsporidia al microscopio óptico. Estudios preliminares de infección en larvas de Aedes aegypti, Culex quinquefasciatus yAnopheles albimanus, criadas en laboratorio, indican que Vavraia sp. infecta las tres especies, con preferencia a Culex quinquefasciatus. Las larvas expuestas a esporas de Amblyospora sp. no presentaron infección. Se discute el posible papel de estos dos géneros en el control de las poblaciones de mosquitos.
Zuluaga Juan S.
The objectives of this research project are to study the chemistry and the biology of oviposition-modifying substances for mosquitoes, to investigate the possibility of applying them in the management of mosquito populations, and to evaluate the role of o...
Y. S. Hwang
Recurrent treatments with Bacillus thuringiensis subsp. israelensis are required to control the floodwater mosquito Aedes vexans that breeds in large numbers in the wetlands of the Bolle di Magadino Reserve in Canton Ticino, Switzerland. Interventions have been carried out since 1988. In the present study, the spatial distribution of resting B. thuringiensis subsp. israelensis spores in the soil was measured. The B. thuringiensis subsp. israelensis concentration was determined in soil samples...
High speed video observations of free flying male Aedes aegypti mosquitoes, the dengue and yellow fever vector, along with custom measurement methods, enable measurement of wingbeat frequency, body position and body orientation of mosquitoes during flight. We find these mosquitoes flap their wings at approximately 850 Hz. We also generate body yaw, body pitch and wing deviation measurements with standard deviations of less than 1 degree and find that sideways velocity and acceleration are important components of mosquito motion. Rapid turns involving changes in flight direction often involve large sideways accelerations. These do not correspond to commensurate changes in body heading, and the insect's flight direction and body heading are decoupled during flight. These findings call in to question the role of yaw control in mosquito flight. In addition, using orientation data, we find that sideways accelerations are well explained by roll-based rotation of the lift vector. In contrast, the insect's body pitch...
Iams, S M
The successful transmission of dengue virus from a human host to a mosquito vector requires a complex set of factors to align. It is becoming increasingly important to improve our understanding of the parameters that shape the human to mosquito component of the transmission cycle so that vaccines and therapeutic antivirals can be fully evaluated and epidemiological models refined. Here we describe these factors, and discuss the biological and environmental impacts and demographic changes that are influencing these dynamics. Specifically, we examine features of the human infection required for the mosquito to acquire the virus via natural blood feeding, as well as the biological and environmental factors that influence a mosquito’s susceptibility to infection, up to the point that they are capable of transmitting the virus to a new host.
Carrington, Lauren B.; Simmons, Cameron P.
The larvicidal activity of 4 plant essential oils--innamon oil, lemon eucalyptus oil, sandalwood oil, and turmeric oil--previously reported as insect repellents was evaluated in the laboratory against 4th instars of Aedes albopictus, Ae. aegypti, and Culex pipiens. Sandalwood oil appeared to be the most effective of the larvicides, killing larvae of all 3 mosquito species in relatively short times. The values of LT50 and LT90 at the application dosage (0.2 mg/ml) were 1.06 +/- 0.11 and 3.24 +/- 0.14 h for Ae. aegypti, 1.82 +/- 0.06 and 3.33 +/- 0.48 h for Ae. albopictus, and 1.55 +/- 0.07 and 3.91 +/- 0.44 h for Cx. pipiens, respectively. Chemical compositions of these essential oils were also studied, and the lavicidal activity of their major ingredient compounds was compared with that of each of the essential oils. The acute toxicity of the 4 essential oils to fathead minnows was also evaluated. The safe use of these natural plant essential oils in future applications of mosquito control was discussed. PMID:18437833
Zhu, Junwei; Zeng, Xiaopeng; O'Neal, Megan; Schultz, Gretchen; Tucker, Brad; Coats, Joel; Bartholomay, Lyric; Xue, Rui-De
Full Text Available Abstract Background Malaria is a serious health issue in Indonesia. Mosquito control is one aspect of an integrated malaria management programme. To focus resources on priority areas, information is needed about the vectors and their habitats. This research aimed to identify the relationship between anopheline mosquitoes and topography in West Timor and Java. Methods Study areas were selected in three topographic types in West Timor and Java. These were: coastal plain, hilly (rice field and highland. Adult mosquitoes were captured landing on humans identified to species level and counted. Results Eleven species were recorded, four of which were significant for malaria transmission: Anopheles aconitus, Anopheles barbirostris, Anopheles subpictus and Anopheles sundaicus. Each species occupied different topographies, but only five were significantly associated: Anopheles annularis, Anopheles vagus and Anopheles subpictus (Java only with hilly rice fields; Anopheles barbirostris, Anopheles maculatus and Anopheles subpictus (West Timor only with coastal areas. Conclusion Information on significant malaria vectors associated with specific topography is useful for planning the mosquito control aspect of malaria management.
Full Text Available Abstract Background Malaria is a major public health issue in much of the world, and the mosquito vectors which drive transmission are key targets for interventions. Mathematical models for planning malaria eradication benefit from detailed representations of local mosquito populations, their natural dynamics and their response to campaign pressures. Methods A new model is presented for mosquito population dynamics, effects of weather, and impacts of multiple simultaneous interventions. This model is then embedded in a large-scale individual-based simulation and results for local elimination of malaria are discussed. Mosquito population behaviours, such as anthropophily and indoor feeding, are included to study their effect upon the efficacy of vector control-based elimination campaigns. Results Results for vector control tools, such as bed nets, indoor spraying, larval control and space spraying, both alone and in combination, are displayed for a single-location simulation with vector species and seasonality characteristic of central Tanzania, varying baseline transmission intensity and vector bionomics. The sensitivities to habitat type, anthropophily, indoor feeding, and baseline transmission intensity are explored. Conclusions The ability to model a spectrum of local vector species with different ecologies and behaviours allows local customization of packages of interventions and exploration of the effect of proposed new tools.
Eckhoff Philip A
Schoenoplectus maritimus (alkali bulrush) has desirable attributes, such as a short growth habit (height of mature stands 3 m) emergent macrophytes in shallow constructed treatment wetlands treating ammonium-dominated wastewater. The effects of different ammonium nitrogen (NH4 -N) levels on alkali bulrush growth and its ability to take up nutrients from the wastewater, as well as on mosquito production, across the range of NH4 -N found in constructed wetlands of southern California are unknown. We evaluated the effects of enrichment with NH4 -N on mosquito production and on the nutrient uptake and growth of alkali bulrush in two studies. Overall, significantly greater numbers (> 50%) of immature mosquitoes (mainly Culex tarsalis) were found in mesocosms enriched with NH4 -N than in mesocosms receiving ambient (<0.3 mg/liter) NH4 -N. High NH4 -N enrichment (up to 60 mg/liter) did not adversely impact the height and stem density of S. maritimus, although a significant decrease in biomass was observed at the highest enrichment level. Nitrogen uptake by alkali bulrush increased directly with NH4 -N enrichment, whereas carbon was conserved in the above-ground biomass across the enrichment gradient. Alkali bulrush is recommended for use as part of integrated mosquito management programs for moderately enriched, multipurpose, constructed treatment wetlands that improve water quality as well as provide wetland habitat for waterfowl. PMID:24820550
Duguma, Dagne; Walton, William E
As part of a program to characterize the plant and animal life of the Laboratory site and the surrounding region, the two breeding bird censuses originated in 1977 were continued in 1980. Coverage was below that of previous years due to illness and travel of some participants, but 11 trips were made to the BNL plot and 8 to the Westhampton plot. Each was censused by separate teams of three volunteer observers. The number of breeding species and number of territorial males on the BNL plot have progressively declined since 1977 but little change has taken place in either number of territories or species composition on the Westhampton plot.
Geographic variation in species richness has been explained by different theories such as energy, productivity, energy-water balance, habitat heterogeneity, and freezing tolerance. This study determines which of these theories best account for gradients of breeding bird richness in China. In addition, we develop a best-fit model to account for the relationship between breeding bird richness and environment in China. Breeding bird species richness in 207 localities (3271 km 2 per locality on average) from across China was related to thirteen environmental variables after accounting for sampling area. The Akaike's information criterion (AIC) was used to evaluate model performance. We used Moran's I to determine the magnitude of spatial autocorrelation in model residuals, and used simultaneous autoregressive model to determine coefficients of determination and AIC of explanatory variables after accounting for residual spatial autocorrelation. Of all environmental variables examined, normalized difference vegetation index, a measure of plant productivity, is the best variable to explain the variance in breeding bird richness. We found that species richness of breeding birds at the scale examined is best predicted by a combination of plant productivity, elevation range, seasonal variation in potential evapotranspiration, and mean annual temperature. These variables explained 47.3% of the variance in breeding bird richness after accounting for sampling area; most of the explained variance in richness is attributable to the first two of the four variables.
Qian, Hong; Wang, Silong; Li, Yuanliang; Wang, Xihua
Mosquito-borne diseases are a major public health threat in Asia. To explore effective mosquito control strategies in rice ecosystems from the ecological point of view, we carried out ecological analyses of vector mosquitoes in Sri Lanka. During the 18-month study period, 14 Anopheles, 11 Culex, 5 Aedes, 2 Mansonia, and 1 Armigeres species were collected, most of which are disease vectors for malaria, filariasis, Japanese encephalitis, or dengue in Sri Lanka and elsewhere in Asia. The density and occurrence of Anopheles and Culex species were the highest in seepage pools and paddy fields, where the majority of niche overlaps between larval mosquito and aquatic insect species were observed. All 7 aquatic insect species, which are larval mosquito predators, overlapped their niche with both Anopheles and Culex larvae. This suggests that conserving these aquatic insect species could be effective in controlling mosquito vectors in the study site. Correlations between several climatic factors and mosquito density were also analyzed, and weather conditions, including higher temperature, lower relative humidity, and higher wind velocity, were found to affect mosquito oviposition, propagation, and survival. These findings deepen our understanding of mosquito ecology and will strengthen future mosquito control strategies in rice ecosystems in Asia. PMID:17883002
Yasuoka, Junko; Levins, Richard
Full Text Available Abstract Background Trade-offs between anti-parasite defence mechanisms and other life history traits limit the evolution of host resistance to parasites and have important implications for understanding diseases such as malaria. Mosquitoes have not evolved complete resistance to malaria parasites and one hypothesis is that anti-malaria defence mechanisms are costly. Results We used matrix population models to compare the population growth rates among lines of Anopheles gambiae that had been selected for resistance or high susceptibility to the rodent malaria parasite, Plasmodium yoelii nigeriensis. The population growth rate of the resistant line was significantly lower than that of the highly susceptible and the unselected control lines, regardless of whether mosquitoes were infected with Plasmodium or not. The lower population growth of malaria-resistant mosquitoes was caused by reduced post blood-feeding survival of females and poor egg hatching. Conclusion With respect to eradicating malaria, the strategy of releasing Plasmodium-resistant Anopheles mosquitoes is unlikely to be successful if the costs of Plasmodium-resistance in the field are as great as the ones measured in this study. High densities of malaria-resistant mosquitoes would have to be maintained by continuous release from captive breeding facilities.
Taylor Pam J
A survey of distribution patterns of floodwater mosquito eggs related to environmental conditions such as moisture and plant associations was conducted by using soil samples from irrigated fields in Wroc?aw, Poland. Mosquito egg distribution was determined by repeatedly flooding the soil samples with aerated water at a temperature of 25° C. Under laboratory conditions, hatching in installments of Aedes caspius (Pallas) and Aedes vexans (Meigen) were commonly observed. The results show that ?75% of the larvae of Ae. caspius and Ae. vexans hatched after the first flooding under summer-like conditions, whereas, following the second and third flooding, the numbers of hatched larvae were significantly lower. In our study, within one intermediate flooded field, a total of 66 plant species was identified and classified into six communities. All vegetation types were associated by varied egg densities and showed differences both in richness and Shannon-Wiener diversity index as well as in ecological indices for moisture, soil reaction, and nutrient level. Small changes in elevation along the slope within the study area showed a large difference in the distribution of mosquito eggs. The highest average egg density was observed in zones with high occurrence of Phalaris arundinacea, usually prevalent in intermediate flooded and fertile areas. Knowledge of the indicators for the distribution of floodwater mosquito eggs in temporary breeding sites may be essential for organizing a successful, integrated mosquito control program with special regard to microbial control agents. PMID:22129404
Rydzanicz, Katarzyna; K?cki, Zygmunt; Jawie?, Piotr
Arbovirus vector dynamics and spread are influenced by climatic, environmental and geographic factors. Major Chikungunya and Dengue fever outbreaks occurring the last 10 years have coincided with the expansion of the mosquito vector Aedes albopictus to nearly all the continents. We characterized the ecological (larval development sites, population dynamics, insemination and daily survival rates) and genetic (diversity, gene flow, population structure) features of two Aedes albopictus populations from distinct environments (rural and urban) on Réunion Island, in the South-West Indian Ocean. Microsatellite analysis suggests population sub-structuring Ae. albopictus populations. Two g