The breeding requirements of three members of the Anopheles gambiae Giles complex (Diptera: Culicidae) in the endemic malaria area of Natal, South Africa

1988 ◽  
Vol 78 (4) ◽  
pp. 549-560 ◽  
Author(s):  
David le Sueur ◽  
Brian L. Sharp

AbstractThe breeding sites used by three species of the Anopheles gambiae Giles complex were investigated in northern Natal, South Africa. Those used by the two freshwater species, A. arabiensis Patton and A. quadriannulatus (Theobald) were similar, immature stages of both being collected from the same pool at five out of seven localities from which A. arabiensis was recorded. A. quadriannulatus was the most extensively distributed species of the complex and was found in association with A. arabiensis at only five of 49 localities. The difficulty in locating the breeding sites of A. arabiensis is a product of their low density, presumably as a result of the intra-domiciliary, residual insecticide spray programme. A. merus Dönitz larvae and pupae were recorded only in water with a salinity greater than 5 p.p.t. The pH, dissolved oxygen, pool size, turbidity, shade and association with vegetation of water bodies containing A. gambiae s.l. were also recorded and showed no difference between the three species. The importance of distinguishing between winter and summer breeding sites is discussed, as well as the need for entomological consultation prior to agricultural development in endemic malarious areas.

2016 ◽  
Vol 8 ◽  
pp. IJIS.S37188 ◽  
Author(s):  
Lame Younoussa ◽  
Elias Nchiwan Nukenine ◽  
Charles Okechukwu Esimone

Mosquitoes are vectors of several human pathogens, and great attention has recently been placed on insecticides from plant-derived products, in search for mosquito control agents. This study, thus, investigated the potency of Boswellia dalzielii methanol leaf extract and its four fractions as mosquito ovicide, larvicide, and pupicide against Anopheles gambiae and Culex quinquefasciatus. The plant products were tested at the following concentrations: 125, 250, 500, 1000, and 2000 ppm on eggs and 312.5, 625, 1250, and 2500 ppm on the larvae and pupae of the mosquitoes. For results, hatchability of A. gambiae eggs was reduced to 5% with n-hexane fraction at 2000 ppm. Among the plant products tested, n-hexane fraction was most toxic against A. gambiae (LC50 = 385.9 ppm) and C. quinquefasciatus (LC50 = 3394.9 ppm). The n-hexane fraction of B. dalzielii might be used as a mosquitocidal agent in the breeding sites of A. gambiae and C. quinquefasciatus.


1973 ◽  
Vol 62 (3) ◽  
pp. 359-369 ◽  
Author(s):  
M. W. Service

Larval populations of the Anopheles gambiae Giles complex (species A and B) were sampled in Kenya, and from the frequencies of the age distribution of the immature stages time-specific life-tables were constructed. Daily survival rates and instar mortalities showed that there was high mortality amongst fourth-instar larvae, due at least in part to infections of larval nematodes, Coelomomyces and epibionts. Antiserum to the A. gambiae complex was prepared in rabbits so that the precipitin test could be employed to detect the presence of A. gambiae in gut smears taken from possible predators. By this serological technique various spiders, Diptera, Coleoptera and amphibia were identified as predators. These may be very important in regulating populations of A. gambiae even in small collections of water.


1973 ◽  
Vol 62 (4) ◽  
pp. 613-625 ◽  
Author(s):  
G. B. White ◽  
P. Rosen

An intensive study was made of the ecology of species A and B of the Anopheles gambiae Giles complex at Kaduna, Nigeria, in October 1971. In collections comprising 383 larvae and 678 adult females from six villages, species A represented 82% of the larvae and 86, 89 and 91% respectively of the adult females caught by spray catches indoors, by biting catches outdoors and by exit traps fitted to windows. Larvae of species A and B occurred together in 42% of 57 breeding sites and showed no differential distribution among the various categories of site. Minor variations among the proportions of A and B females captured by different methods in the six villages showed no consistent contrasts. The only significant variation of the A/B ratio occurred at a temporary Fulani camp of cattle herdsmen, near Anguwun Maaza village, where an enhanced number of species B females were present indoors. At this Fulani camp a considerable number of both A and B females were feeding on cows outdoors and resting indoors during the day. Human blood indices of indoor-resting females were 88% for species A and 39% for species B at this camp, compared with 100% for both species at villages without cattle. Larval breeding places harboured an expectable range of insect predators. Predators of adult A. gambiae were not investigated although a predacious Emesine bug, Tinna elongata Villiers, was recorded in some huts. Numerous pathogen infections of larvae were observed, namely, Thelohania in 19%, Coelomomyces in 16%, unidentified gregarines in 7% and black-body virus in 3% of gambiae-positive breeding sites. Thelohania, Coelomomyces and gregarine infections were also encountered in adult females. Malaria sporozoite rates were 9·3% in species A and 5·5% in species B females. Some infections of stage III larvae of Wuchereria bancrofti were also seen in species A females.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Armel Djènontin ◽  
Aziz Bouraima ◽  
Christophe Soares ◽  
Seun Egbinola ◽  
Gilles Cottrell

Abstract Objective In the framework of EVALMOUS study aiming to assess the use and effectiveness of mosquito nets by pregnant women and other members of their household in a lagoon area in southern Benin, the behaviour of pregnant women relative to the time they go to bed using the net were recorded. Malaria vectors biting rhythm, Plasmodium falciparum infection and insecticide resistance genes in malaria vectors were also determined. Results Overall, 3848 females of Anopheles gambiae s. l were collected and 280 pregnant women responded to the survey. Almost all Anopheles gambiae s. l. tested were Anopheles coluzzi Coetzee and Wilkerson 2013 (Diptera: Culicidae). The CSP index in malaria vector was 1.85% and the allelic frequency of kdr gene was 74.4%. Around 90% of bites and Plasmodium falciparum Welch, 1897 (Haemosporida: Plasmodiidae) transmission occurred between 10 p.m. and 6 a.m., which coincides with the period when more than 80% of pregnant women were under bednet. Despite a slight early evening and early morning biting activity of malaria vectors in the study area, the good use of nets might remain a useful protection tool against mosquito biting and malaria transmission.


1954 ◽  
Vol 45 (2) ◽  
pp. 361-373 ◽  
Author(s):  
M. T. Gillies

The behaviour of Anopheles gambiae Giles and A. funestus Giles was studied under natural conditions in a lowland area of Tanganyika.Studies on the outside resting population were carried out by direct searching for natural resting sites, and by the use of artificial box shelters partly buried in the ground in shaded localities. Catches in these give a valid sample when set up at some distance from houses.Fed and gravid females comprised 67 per cent. of the outside resting gambiae population, the latter group being between 12 and 4·5 times as numerous as the former. Rather less than half the funestus females caught were unfed, the remainder of the population being mainly composed of gravid females.Precipitin tests on the small numbers of fed females caught outside were nearly all positive for man.The identification of gravid funestus females was confirmed by periodic examination of the eggs.Entry of females into outside shelters did not occur solely in the period around sunrise. An appreciable number of funestus females did not enter before 07.00 hours and this was particularly so in shaded shelters.The building of a hut in the vicinity of a box shelter caused a drastic reduction in the numbers of mosquitos resting in the latter.Outside biting activity in these two species is of negligible importance as a source of females resting outside.


1993 ◽  
Vol 27 (4) ◽  
pp. 227-236 ◽  
Author(s):  
Oswaldo Paulo Forattini ◽  
Iná Kakitani ◽  
Eduardo Massad ◽  
Daniel Marucci

A relation between a rice irrigation system and mosquito breeding was established in a study undertaken at the Ribeira Valley Experimental Station, from January through December 1992. Flooding favoured Anopheles (Nyssorhynchus) and Culex (Melanoconion) species, while empty paddies condition were propitious to Aedes scapularis and Culex (Culex) species. Compared with a more primitive area of the same region, several species showed high a degree of adaptation to the anthropic environment. Among them, Anopheles albitarsis, a potential malaria vector that breeds in the irrigation system, has shown immature stage production thirteen times higher than at the natural breeding sites. In addition, Ae. scapularis, An. oswaldoi, Cx. bastagarius, and Cx. chidesteri presented high levels of synanthropy.


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