scholarly journals Behavioural and antennal responses of Aedes aegypti (l.) (Diptera: Culicidae) gravid females to chemical cues from conspecific larvae

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0247657
Author(s):  
Antoine Boullis ◽  
Margaux Mulatier ◽  
Christelle Delannay ◽  
Lyza Héry ◽  
François Verheggen ◽  
...  

Mass trapping of gravid females represents one promising strategy for the development of sustainable tools against Aedes aegypti. However, this technique requires the development of effective odorant lures that can compete with natural breeding sites. The presence of conspecific larvae has been shown to stimulate oviposition. Hence, we evaluated the role of four major molecules previously identified from Ae. aegypti larvae (isovaleric, myristoleic, myristic [i.e. tetradecanoic], and pentadecanoic acids) on the oviposition of conspecific females, as well as their olfactory perception to evaluate their range of detection. Using flight cage assays, the preference of gravid females to oviposit in water that previously contained larvae (LHW) or containing the four larval compounds was evaluated. Then, compounds and doses inducing the highest stimulation were challenged for their efficacy against LHW. Only isovaleric acid elicited antennal response, suggesting that the other compounds may act as taste cues. Pentadecanoic acid induced significant oviposition stimulation, especially when dosed at 10 ppm. Myristoleic acid and isovaleric acid deterred oviposition at 10 and 100 ppm, while no effect on oviposition was observed with myristic acid irrespectively of the dose tested. When the four compounds were pooled to mimic larvae’s chemical signature, they favored oviposition at 1 ppm but negatively affected egg-laying at higher concentrations. When properly dosed, pentadecanoic acid and the blend of compounds may be promising lures for ovitraps as they could compete with LHW. Due to their low volatility, their effect should be further evaluated under field conditions, in addition with long-range attractants for developing effective tools against gravid females.

2019 ◽  
Vol 53 ◽  
pp. 29 ◽  
Author(s):  
Gerson Laurindo Barbosa ◽  
Mariana De Oliveira Lage ◽  
Valmir Roberto Andrade ◽  
Antônio Henrique Alves Gomes ◽  
Jose Alberto Quintanilha ◽  
...  

OBJECTIVE: To evaluate whether sites with large amount of potential breeding sites for immature forms of Aedes aegypti, called strategic points, influence in the active vector’s dispersion into properties in their surroundings. METHODS: We selected four areas in the municipality of Campinas, three of them with strategic points classified as high, moderate, and low risk according to infestation and a control area, without strategic points. Between October 2015 and September 2016, we monthly installed oviposition traps and evaluated the infestation by Ae. aegypti in all properties of each selected area. To verify if there was vector dispersion from each strategic point, based on its location, we investigated the formation of clusters with excess of eggs or larvae or pupae containers, using the Gi spatial statistics. RESULTS: The amount of eggs collected in the ovitraps and the number of positive containers for Ae. aegypti did not show clusters of high values concerning its distance from the strategic point. Both presented random distribution not spatially associated with the positioning of strategic points in the area. CONCLUSIONS: Strategic points are not confirmed as responsible for the vector’s dispersion for properties in their surroundings. We highlight the importance of reviewing the current strategy of the vector control program in Brazil, seeking a balance from the technical, operational, and economic point of view, without disregarding the role of strategic points as major producers of mosquitoes and their importance in the dissemination of arboviruses in periods of transmission.


2012 ◽  
Vol 2012 ◽  
pp. 1-3 ◽  
Author(s):  
Joël Gustave ◽  
Florence Fouque ◽  
Sylvie Cassadou ◽  
Lucie Leon ◽  
Gabriel Anicet ◽  
...  

During the past ten years, the islands of Guadeloupe (French West Indies) are facing dengue epidemics with increasing numbers of cases and fatal occurrences. The vectorAedes aegyptiis submitted to intensive control, with little effect on mosquito populations. The hypothesis that importantAe. aegyptibreeding sites are not controlled is investigated herein. For that purpose, the roof gutters of 123 houses were systematically investigated, and the percentage of gutters positive forAe. aegyptivaried from 17.2% to 37.5%, from humid to dry locations. In the dryer location, most of houses had no other breeding sites. The results show that roof gutters are becoming the most importantAe. aegyptibreeding sites in some locations in Guadeloupe, with consequences on dengue transmission and vector control.


PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0250893
Author(s):  
Alvaro E. Eiras ◽  
Laila H. Costa ◽  
Luciane G. Batista-Pereira ◽  
Kelly S. Paixão ◽  
Elis P. A. Batista

The mosquito Aedes aegypti is the main vector of arboviroses and current approaches to control this vector are not sufficiently effective. Adult traps, such as the BG-Sentinel (BGS), have been successfully used for mosquito surveillance and can also suppress vector populations. A new “passive” trap for gravid Ae. aegypti (Gravid Aedes Trap—GAT) has been shown efficient for Aedes collection and suppress Ae. albopictus populations using mass trapping techniques. Here the GAT was evaluated for the first time as a new tool to control Ae. aegypti in semi-field conditions using simulated outdoor environments (SOE). Two identical large screened chambers inside of a SOE containing different numbers and sizes of artificial breeding sites were used to assess the trapping efficiency of the GAT. One hundred mosquitoes were released into the chambers, and recapture rates evaluated after 48h. The parity status of the captured mosquitoes was also recorded. The number of eggs laid, and breeding productivity were also monitored when using different numbers and sizes of breeding sites. The BGS trap was used here as a control (gold standard) trap to compare capture rates to those of the GAT. The GAT recaptured between 50–65% of the mosquitoes independent of the number and sizes of the breeding sites in the SOEs, whereas the BGS recaptured 60–82% of the females. Both traps showed similar results regarding to the parity status of recaptured mosquitoes. Our results confirmed the effectiveness of GAT for the capture of adult female Ae. aegypti in simulated field environments. The BGS trap recaptured gravid Ae. aegypti before egg-laying in different sizes and number of breading sites, whereas the oviposition activity occurred prior to recapture mosquitoes in the GAT. Based on the results, we believe that GAT is a promising candidate for mass-trapping intervention in urban settings, but a source reduction intervention should be made prior trap deployment. Therefore, we suggest future field studies to confirm the use of GAT as a complementary tool in vector control activities.


1983 ◽  
Vol 31 (6) ◽  
pp. 925 ◽  
Author(s):  
WD Atkinson

Laboratory experiments showed that the previously reported tendency of D. melanogaster females to lay their eggs close to other Drosophila eggs and larvae, was really a response to surface texture. Oviposition was encouraged by a rough surface, and the presence of eggs and larvae on smooth food medium provided sufficient surface texture to stimulate egg-laying. Such an effect would certainly not be significant in natural breeding sites.


2020 ◽  
Author(s):  
Paula V Gonzalez ◽  
Laura Harburguer

Abstract BACKGROUND Aedes aegypti (L.) is the main vector of dengue, yellow fever, Zika and chikungunya viruses. A new method for controlling this mosquito has been developed based on the possibility that wild adult mosquitoes exposed to artificial resting sites contaminated with a larvicide, can disseminate it to larval breeding sites, is named ‘‘autodissemination’’. The present study was undertaken to evaluate if a chitin synthesis inhibitor like lufenuron can by disseminated to larval breeding sites and prevent adult emergence and also if forced contact of Ae. aegypti females with treated surfaces can affect its fertility, fecundity and blood in take capaity.METHODSLarval susceptibility to lufenuron was measured through EI50 and EI90. On the other hand gravid females were exposed by tarsal contact to lufenuron-treated papers, we used the WHO susceptibility test kit tube to line the papers, and 1, 3 or 5 females for the transference. We also evaluate if the exposure of mosquito females to lufenuron-treated papers (0.4 and 1 mg a.i./cm 2 ) has an effect on their fecundity, fertility or in the ability to feed on blood. In each assay 12-15 mosquito females were exposed to lufenuron for 1 hour; 24 h before (before blood meal - BBM) or 24 h after a blood meal (ABM).RESULTSLufenuron proved to be very active against Ae. aegypti larvae with an EI 50 of 0.164 ppb and EI 95 of 1.26 ppb. We also found that lufenuron can be transferred by females from treated surfaces to clean containers causing the inhibition of emergence of the larvae (between 30 and 50%). This effect was dependent on the concentration applied on the paper and also the number of females added to each cage.CONCLUSIONSThis paper introduces an innovation by first exploring the possibility that an IGR belonging to the group of benzoylphenyl ureas, such as lufenuron, can be transferred by gravid females to breeding sites and that at the same time can have an effect on fertility, fertility and blood intake capacity of adult mosquitoes.


2016 ◽  
Vol 50 (0) ◽  
Author(s):  
Tamara Nunes Lima-Camara ◽  
Paulo Roberto Urbinatti ◽  
Francisco Chiaravalloti-Neto

ABSTRACT This is the description of how nine Aedes aegypti larvae were found in a natural breeding site in the Pinheiros neighborhood, city of Sao Paulo, SP, Southeastern Brazil. The record was conducted in December 2014, during an entomological surveillance program of dengue virus vectors, with an active search of potential breeding sites, either artificial or natural. Finding Ae. aegypti larvae in a tree hole shows this species’ ability to use both artificial and natural environments as breeding sites and habitats, which points towards the importance of maintaining continuous surveillance on this mosquito in all kinds of water-holding containers.


2020 ◽  
Author(s):  
Paula V Gonzalez ◽  
Laura Harburguer

Abstract Background: Aedes aegypti (L.) is the main vector of dengue, yellow fever, Zika and chikungunya viruses. A new method for controlling this mosquito has been developed based on the possibility that wild adult mosquitoes exposed to artificial resting sites contaminated with a larvicide, can disseminate it to larval breeding sites, is named ‘‘auto-dissemination’’. The present study was undertaken to evaluate if a chitin synthesis inhibitor like lufenuron can by disseminated to larval breeding sites and prevent adult emergence and also if forced contact of Ae. aegypti females with treated surfaces can affect its fertility, fecundity and blood intake capacity. Methods: Larval susceptibility to lufenuron was measured through EI 50 and EI 90 . On the other hand gravid females were exposed by tarsal contact to lufenuron-treated papers, we used the WHO susceptibility test kit tube to line the papers, and 1, 3 or 5 females for the transference. We also evaluated if the exposure of mosquito females to lufenuron-treated papers (0.4 and 1 mg a.i./cm 2 ) has an effect on their fertility, fecundity or in the ability to feed on blood. In each assay 12-15 mosquito females were exposed to lufenuron for 1 hour; 24 h before (before blood meal - BBM) or 24 h after a blood meal (ABM). Results: Lufenuron proved to be very active against Ae. aegypti larvae with an EI 50 of 0.164 ppb and EI 90 of 0.81 ppb. We also found that lufenuron can be transferred by females from treated surfaces to clean containers causing the inhibition of emergence of the larvae (between 30 and 50%). This effect was dependent on the concentration applied on the paper and also the number of females added to each cage. Conclusions: This paper introduces an innovation by first exploring the possibility that an IGR belonging to the group of benzoylphenyl ureas, such as lufenuron, can be transferred by gravid females to breeding sites and that at the same time can have an effect on fertility, fecundity and blood intake capacity of adult mosquitoes. Keywords: Aedes aegypti , lufenuron, auto-disemination, fertility, fecundity.


1995 ◽  
Vol 16 (3) ◽  
pp. 265-272 ◽  
Author(s):  
Claude Miaud

AbstractOviposition site selection in Triturus helveticus, T. alpestris and T. cristatus was studied both in natural and laboratory situations. In a natural breeding site, eggs of the three species were not laid equally on several plants: T. cristatus laid practically all their egges on only one plant (Nasturtium officinale) while T. helveticus eggs were collected on four plant species. In laboratory experiments, plastic and cotton fabric supports made it possible to test ovipositing female selectivity according to flexibility and shape of support and egg-laying distance below the surface. In all three species, a high proportion of eggs were laid on supports of linear shape (as opposed to arborescent shape) and egg frequency decreased as a function of depth (from 0 to 40 cm below the surface). Selection according to flexibility was also observed, the smallest species (T. helveticus) laying more eggs on the thinner supports. The role of support selectivity during oviposition in Triturus is discussed, in term of proximate (i.e. female protection against predators, breathing necessity) and ultimate (i.e. egg survival) factors, and related to new ecology.


1955 ◽  
Vol 46 (3) ◽  
pp. 711-742 ◽  
Author(s):  
C. Teesdale

Studies have been made of the bionomics and ecology of Aëdes aegypti (L.) entirely under natural conditions and in its natural habitats on the Kenya coast.Development from egg to adult under conditions approximating as nearly as possible to those in nature took a minimum of eight days and a maximum of twenty-five.Males were in excess of females, in the proportion seventeen to ten, from eggs hatched in natural breeding places.Although the mosquito may be able to propagate in houses, adults from outside habitually enter premises. If this entry is for egg-laying, then eradication by domestic larval control alone, although reputedly achieved elsewhere, is not possible under conditions obtaining in the coastal belt of Kenya. Windowtrap captures, however, indicate that the entry may not be for the purpose of egg-laying.The seasonal reduction of both larvae and adults in houses during the hot, dry months of February and March is attributed to a combination of the absence of breeding places outside and the shorter life span of the mosquito at this time.It is shown that both sexes enter and leave native huts throughout the 24-hour period, but the movement is confined almost wholly to the hours of daylight. The flight from houses is much reduced in the cool months (July and August). This corresponds with the season when most enter.


2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Abdurrakhman abdurrakhman Abdurrakhman

ABSTRACT : The House index and Container Index in the buffer area of ​​the working area of ​​Balikpapan Sepinggan Airport is still above 1%, so the potential for the spread of dengue disease. Mobilization of people, goods and transportation equipment will increasingly affect the transmission of disease in ports and airports, especially for vector-borne diseases. This study aims to analyze the risk factors associated with larvae density of Aedes aegypti and describe the larvae index in the buffer zone of the Sepinggan Balikpapan Airport This study was a descriptive study with a cross sectional design. The sample in this study was 121 houses with a proportionate stratified random sampling, the research location was in the buffer zone of Sepinggan Balikpapan Airport in November 2018. The variables studied were houses with positive larvae containers, breeding sites and PSN behavior and larvasidation. The data was analyzed using the chi square test. There was a relationship between houses with larvae positive Aedes aegypti, behavior of Mosquito Nest Eradication (PSN) and larvasidation with larvae density of Aedes aegypti but not for breeding sites (p = 0.00 and 95% CI = 0.64), and   (p = 0.00 and 95% CI = 0.34). The description of several Aedes aegypti larvae index, namely House Index (HI) = 57.02%, Container Index (CI) = 24.36%, Bruteau Index (BI) = 148.76, and Flick Free Numbers (ABJ) = 42.98 %. Houses with larvae of Aedes aegypti larvae and PSN and larvasidation behavior were associated with larvae density of Aedes aegypti. The index of HI, CI and BI larvae is of high value so there is a risk of DBD transmission


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