scholarly journals Semi-field assessment of the Gravid Aedes Trap (GAT) with the aim of controlling Aedes (Stegomyia) aegypti populations

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.

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.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Léa Douchet ◽  
Marion Haramboure ◽  
Thierry Baldet ◽  
Gregory L’Ambert ◽  
David Damiens ◽  
...  

AbstractThe expansion of mosquito species worldwide is creating a powerful network for the spread of arboviruses. In addition to the destruction of breeding sites (prevention) and mass trapping, methods based on the sterile insect technique (SIT), the autodissemination of pyriproxyfen (ADT), and a fusion of elements from both of these known as boosted SIT (BSIT), are being developed to meet the urgent need for effective vector control. However, the comparative potential of these methods has yet to be explored in different environments. This is needed to propose and integrate informed guidelines into sustainable mosquito management plans. We extended a weather-dependent model of Aedes albopictus population dynamics to assess the effectiveness of these different vector control methods, alone or in combination, in a tropical (Reunion island, southwest Indian Ocean) and a temperate (Montpellier area, southern France) climate. Our results confirm the potential efficiency of SIT in temperate climates when performed early in the year (mid-March for northern hemisphere). In such a climate, the timing of the vector control action was the key factor in its success. In tropical climates, the potential of the combination of methods becomes more relevant. BSIT and the combination of ADT with SIT were twice as effective compared to the use of SIT alone.


Author(s):  
Jaroslav Urban

The paper deals with the occurrence, development and harmfulness of Deporaus betulae (L.). The majority of field studies was carried out at Training Forest Enterprise (TFE) Masaryk Forest in Křtiny (District Brno-venkov) in 2010 and 2011. In addition to this, the species was studied in detail also in a laboratory. It occurred mostly on Betula pendula and Carpinus betulus. Rarely, the species was found on Alnus glutinosa and Corylus avellana and only sporadically on Fagus sylvatica, Quercus petraea, Tilia cordata and T. platyphyllos. In the studied area, larvae and pupae hibernate. Beetles occur on trees from the end of April to the beginning of July, sporadically later. Females lay on average 2.5 (in the laboratory 4.4) eggs into rolls on B. pendula, on C. betulus 2.2 eggs. During two months, they damage on average 5.3 cm2 leaves creating 14 rolls and laying 35 eggs into the rolls. Larvae consume only 1.7 cm2 leaf blade. The development of the species takes three to four months from egg laying to the departure of larvae into soil. On leaves of B. pendula of an average area of 14.2 cm2, females roll up the same area (about 11.2 cm2) as on leaves of C. betulus of an area of 21.7 cm2. Into the rolls, they lay on average the same number of eggs. The average number of eggs in rolls increases with the increased area of B. pendula leaf blade. Trees partly compensate for the reduction of assimilatory area also by the growth of the area of neighbouring undamaged leaves (on average by 12.7 %).


Pathogens ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1521
Author(s):  
Donato Antonio Raele ◽  
Francesco Severini ◽  
Daniela Boccolini ◽  
Michela Menegon ◽  
Luciano Toma ◽  
...  

Malaria still represents a potential public health issue in Italy, and the presence of former Anopheles vectors and cases imported annually merit continuous surveillance. In areas no longer endemic, the concurrent presence of gametocyte carriers and competent vectors makes re-emergence of local transmission possible, as recently reported in Greece. In October 2017, due to the occurrence of four suspected introduced malaria cases in the province of Taranto (Apulia region), entomological investigations were performed to verify the involvement of local anopheline species. In 2019–2020 entomological surveys were extended to other areas historically prone to malaria between the provinces of Taranto and Matera and the province of Foggia (Gargano Promontory). Resting mosquitoes were collected in animal shelters and human dwellings, larvae were sampled in natural and artificial breeding sites, and specimens were both morphologically and molecularly identified. A total of 2228 mosquitoes were collected, 54.3% of which were anophelines. In all the investigated areas, Anopheles labranchiae was the most widespread species, while Anopheles algeriensis was predominant at the Gargano sites, and Anopheles superpictus and Anopheles plumbeus were recorded in the province of Matera. Our findings showed a potentially high receptivity in the surveyed areas, where the abundance of the two former malaria vectors, An. labranchiae and An. superpictus, is related to environmental and climatic parameters and to anthropic activities.


2021 ◽  
Vol 3 (2) ◽  
pp. 078-082
Author(s):  
Abdelmonem Eltiyab Houmida Ali ◽  
Mutaman Ali A. Kehail

There are many methods used for mosquito control. Depending on the situation, source reduction (removing stagnant water), bio-control (importing natural predators), trapping, and insecticides to kill larvae or adults may be used. Some aquatic predators were reputed as biological control agents for mosquito larvae. Hence they have to be considered when experimenting on the lethal effects of any material on mosquito larvae. The objectives of this study were to study the effects of neem leaves and usher latex against Anopheles and Culex larvae and some of their aquatic predators (hemipteran boatman (HB), tadpole (T), swimming beetle larvae (SBL) and adult (SBA) and mayfly naiad (MF)) in some breeding sites around Wad Medani Town. Gezira State, Sudan. Two villages were selected for conducting this study. The count of the mosquito larvae and the aquatic predators continued for four days from applying natural products. The results showed that, mosquito’s larvae were affected more than the aquatic by Neem leaves and Ushar latex. The study of the microclimates in the breeding sites will help to correlate toxicity to any level of any environmental factor.


2010 ◽  
Vol 56 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Kelly A. Stiver ◽  
Suzanne H. Alonzo

Abstract Theory suggests that males that are larger than their competitors may have increased mating success, due to both greater competitive ability and increased attractiveness to females. We examined how male mating success varies with male size in the tessellated darter Etheostoma olmstedi. Previous work has shown that large males tend to move around and breed in vacant breeding sites, and consequently provide less care for their eggs, while smaller individuals can be allopaternal, caring for the eggs of other males as well as for their own. We studied female egg deposition in a natural breeding population using artificial breeding sites and in the laboratory, where female choice of spawning site was restricted to two breeding sites tended by two males of different sizes. In both the field and the laboratory, nests tended by larger males were more likely to receive new eggs. Additionally, the mean size of males associated with a nest was positively correlated with both the maximum coverage of eggs at the nest and the number of times new eggs were deposited. We discuss how the increased mating success of larger males, despite their decreased parental care, may help explain allopaternal care in this species.


Insects ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 251 ◽  
Author(s):  
Ying-An Chen ◽  
Yi-Ting Lai ◽  
Kuo-Chih Wu ◽  
Tsai-Ying Yen ◽  
Chia-Yang Chen ◽  
...  

The policy regarding mosquito control strategies in Taiwan is based on integrated vector management (IVM). The major approach is source reduction via collaboration by both residents and governments. However, small and cryptic habitats of dengue vectors are hard to find and eliminate in urban communities. Therefore, this study evaluated a complementary approach that targeted cryptic habitats by utilizing mosquitoes themselves as vehicles to transfer an insect growth regulator, pyriproxyfen (PPF), to their breeding sites; the amount of PPF in breeding water was determined with ultra-performance liquid chromatography coupled with tandem mass spectrometry (UPLC–MS/MS). A bioassay conducted by introducing ten late-instar larvae into PPF solution was performed to assess emergence inhibition (EI). PPF was found at 0.56 ± 0.04 ng in 25 mL of water by dissemination via ten Aedes aegypti mosquitoes exposed to 0.01% PPF, leading to 100% EI. After the community-level source reduction, a field trial in Kaohsiung in Southern Taiwan showed that 30.8–31.5% of cryptic ovitraps reached EI ≥ 50% one month after spraying 0.01% PPF in microhabitats favored by mosquitoes. IVM in parallel with residual spraying of PPF on resting surfaces of mosquitoes could serve as a simple and complementary approach to reduce cryptic larval sources in urban communities in Southern Taiwan.


2017 ◽  
Vol 27 (4) ◽  
pp. 1155-1166 ◽  
Author(s):  
Christopher J. W. McClure ◽  
Benjamin P. Pauli ◽  
Julie A. Heath

1996 ◽  
Vol 31 (3) ◽  
pp. 277-285 ◽  
Author(s):  
R. R. Youngman ◽  
T. P. Kuhar ◽  
D. G. Midgarden

Field studies were conducted in Virginia cornfields in 1990 and 1991 to evaluate the effect of trap size on numbers of Diabrotica virgifera virgifera LeConte adults caught on unbaited Pherocon AM and Olson yellow sticky traps. No significant differences in trapping efficiency (i.e., catch per unit area) were detected on Pherocon AM traps whose sizes had been reduced by either 50% or 75% when compared with standard Pherocon AM no-bait traps. Likewise, no significant difference in trapping efficiency was detected between Olson traps whose sizes had been reduced 50% and full-size Olson traps (212.9 cm2). However, significantly more western corn rootworm adults per unit area were caught on Olson yellow sticky traps compared to Pherocon AM traps whose sizes had been reduced 50%. Comparative costs and precision values for reduced-size Pherocon AM and Olson yellow sticky traps are discussed.


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