scholarly journals Effect of Larval Nutritional Regimes on Morphometry and Vectorial Capacity of Aedes aegypti for Dengue Transmission

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Nayana Gunathilaka ◽  
Hasini Upulika ◽  
Lahiru Udayanga ◽  
Deepika Amarasinghe
Keyword(s):  
Survival Rate ◽  
Sri Lanka ◽  
Aedes Aegypti ◽  
Adult Emergence ◽  
Bovine Liver ◽  
Vectorial Capacity ◽  
Head Width ◽  
Larval Diet ◽  
Larval Food ◽  
Emergence Rate

Background. Nutritional level in larval diet of mosquito vectors influence on life history traits and vectorial capacity (VC). Therefore, the present study was carried out to assess the effect of larval diet concentration on vector bionomic and VC of Aedes aegypti in Sri Lanka. Method. Three batches of 400 Ae. aegypti larvae (first instar) were reared under different concentrations of larval diet (6%, 8%, and 10%; Volume/Volume), which was prepared by mixing 12.5 g of tuna meal, 9.0 g of bovine liver powder, and 3.5 g of Brewer’s yeast, in 100 ml of distilled water. The effect of larval diet concentration on different morphometric and functional parameters of larvae (length and width of head, abdomen, survival rate, and pupation success), pupae (length and width of cephalothorax, survival rate, and adult emersion), adult (length and width of thorax, abdomen, survival rate, longevity, biting frequency and fecundity of adults) were examined. In addition, VC of Ae. aegypti was evaluated. The General Linear Model (GLM) was used for the statistical analysis. Results. Larval head length, head width, thoracic width, abdominal length, abdominal width, total length, and survival rate significantly increased with higher doses of larval diet (P<0.05). In case of pupae, length, and width of cephalothorax, survival rate and adult emergence rate denoted an increasing trend with the elevated larval diets. However, the variations of survival rate and adult emergence rate were statistically significant (P<0.05). In adults, all morphometric parameters (thoracic length, abdominal length, abdominal width, and wing length) significantly increased with elevating larval diets levels (except for thoracic width) along with the biting frequency, fecundity, and survival rate (P<0.05) of adult females. The VC also denoted significant variations (F4,14 = 24.048; P<0.05) with the larval diet concentration, whereby the highest VC of 196.37 was observed at 10% treatment. Conclusion. Larval food availability has a significant influence on the adult fitness and thus may affect the incidence of dengue due to variations in the VC of Ae. aegypti. Hence, this investigation highlights the requirement in accounting the environmental variation at the larval stages in order to understand transmission dynamics and control of dengue in Sri Lanka.

Development of an Alternative Low-Cost Larval Diet for Mass Rearing of Aedes aegypti Mosquitoes In Sri Lanka

2020 ◽  
Author(s):  
Umesha Senevirathna ◽  
Lahiru Udayanga ◽  
Mangala Ganehiarachchi ◽  
Menaka Hapugoda ◽  
Tharaka Ranathunge
Keyword(s):  
Sri Lanka ◽  
Aedes Aegypti ◽  
Low Cost ◽  
Mass Rearing ◽  
Head Width ◽  
Larval Diet ◽  
Larval Size ◽  
Energy Agency ◽  
Developmental Parameters ◽  
Adult Fitness

Abstract Background Aedes aegypti is a major vector of arboviruses that may be controlled on an area-wide basis using novel approaches such as Sterile Insect Technique (SIT) and Incompatible Insect Technique (IIT). Larval diet is a major factor in mass-rearing of Aedes mosquitoes for SIT and IIT programs. Therefore, current study aimed to evaluate the effects of two novel diets developed from dry fish powder on growth and development of immature stages and adult fitness-related characteristics of Ae. aegypti in Sri Lanka. Method: Three batches of 250 Ae. aegypti first instar larvae were exposed to three different larval diets as, standard dry fish powder (D1), dry fish powder meal and brewer’s yeast (D2) and International Atomic Energy Agency (IAEA) reccomanded diet (D3), separately. Morphometric and developmental parameters of 4th instar larvae, pupae and adult mosquitoes reared under different dietary treatments were measured. General Linear Model (GLM) was used for statistical analysis. Results Significant diet-based variations were observed in the head length, head width, thoracic length, thoracic width, abdominal length, abdominal width and total length (F2, 87>4.811; P < 0.05) of Ae. aegypti larvae. The highest pupation success and the larval size were observed from the larvae fed with D2 diet, while the lowest was reported from D1. All adult morphometric parameters of adult male and female Ae. aegypti mosquitoes also denoted significant dietary variations, reporting the best sized adults from D2 diet (F2, 87>3.54; P < 0.05). Further, significantly higher fecundity and male longevity were also shown by the adult Ae. aegypti (F2, 6>7.897; P < 0.01) reared under diet D2. Conclusion Based on all the growth and developmental parameters, D2 diet reported the best quality adult mosquitoes similar to the IAEA recomanded diet, while being more inexpensive. Therefore, larval diet D2 could be recomaded as the ideal diet for for mass-rearing of Ae. aegypti for IIT and SIT-based vector control in Sri Lanka.

scholarly journals Development of an Alternative Low-Cost Larval Diet for Mass Rearing of Aedes aegypti Mosquitoes

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Umesha Senevirathna ◽  
Lahiru Udayanga ◽  
G.A.S.M. Ganehiarachchi ◽  
Menaka Hapugoda ◽  
Tharaka Ranathunge ◽  
...  
Keyword(s):  
Sri Lanka ◽  
Aedes Aegypti ◽  
Low Cost ◽  
Critical Factor ◽  
Mass Rearing ◽  
Head Width ◽  
Larval Diet ◽  
Larval Size ◽  
Energy Agency ◽  
Developmental Parameters

Background. Aedes aegypti is a major vector of arboviruses that may be controlled on an area-wide basis, using novel approaches such as Sterile Insect Technique (SIT) and Incompatible Insect Technique (IIT). Larval diet is a critical factor to be considered in mass rearing of Aedes mosquitoes for SIT and IIT programs. Therefore, the current study is aimed at evaluating the effects of two novel diets developed from dry fish powder on the growth and development of immature stages and adult fitness-related characteristics of Ae. aegypti in Sri Lanka. Method. Three batches of the first instar Ae. aegypti larva, each containing 250 larvae, were exposed to three different larval diets as standard dry fish powder (D1), dry fish powder meal and brewer’s yeast (D2), and International Atomic Energy Agency- (IAEA-) recommended diet (D3), separately. Morphometric and developmental parameters of the 4th instar larvae, pupae, and adult mosquitoes reared under different dietary treatments were measured. The entire experimental setup was replicated thrice. A General Linear Model (GLM) in the form of two-way ANOVA was used for the statistical analysis. Results. Significant diet-based variations were observed in the head length, head width, thoracic length, thoracic width, abdominal length, abdominal width, and total length ( F 2 , 87 > 4.811 ; P < 0.05 ) of Ae. aegypti larvae. The highest pupation success and the larval size were observed from the larvae fed the D2 diet, while the lowest was reported from D1. All adult morphometric parameters of adult male and female Ae. aegypti mosquitoes also denoted significant dietary variations, reporting the best-sized adults from the D2 diet ( F 2 , 87 > 3.54 ; P < 0.05 ). Further, significantly higher fecundity and male longevity were also shown by the adult Ae. aegypti ( F 2 , 6 > 7.897 ; P < 0.01 ) mosquitoes reared under diet D2. Conclusion. Based on all the growth and developmental parameters, the D2 diet tends to perform similar to the IAEA-recommended diet in mass rearing of Ae. aegypti mosquitoes, while being more inexpensive. Therefore, larval diet D2 could be suggested as the ideal diet for mass rearing of Ae. aegypti for IIT and SIT-based vector control in Sri Lanka.

scholarly journals Larval Diet Abundance Influences Size and Composition of the Midgut Microbiota of Aedes aegypti Mosquitoes

2021 ◽  
Vol 12 ◽  
Author(s):  
Hannah J. MacLeod ◽  
George Dimopoulos ◽  
Sarah M. Short
Keyword(s):  
Aedes Aegypti ◽  
Bacterial Load ◽  
Amplicon Sequencing ◽  
Larval Diet ◽  
Microbiota Composition ◽  
Vector Species ◽  
Larval Food ◽  
Disease Vector ◽  
16S Amplicon Sequencing ◽  
The Impact

The midgut microbiota of the yellow fever mosquito Aedes aegypti impacts pathogen susceptibility and transmission by this important vector species. However, factors influencing the composition and size of the microbiome in mosquitoes are poorly understood. We investigated the impact of larval diet abundance during development on the composition and size of the larval and adult microbiota by rearing Aedes aegypti under four larval food regimens, ranging from nutrient deprivation to nutrient excess. We assessed the persistent impacts of larval diet availability on the microbiota of the larval breeding water, larval mosquitoes, and adult mosquitoes under sugar and blood fed conditions using qPCR and high-throughput 16S amplicon sequencing to determine bacterial load and microbiota composition. Bacterial loads in breeding water increased with increasing larval diet. Larvae reared with the lowest diet abundance had significantly fewer bacteria than larvae from two higher diet treatments, but not from the highest diet abundance. Adults from the lowest diet abundance treatment had significantly fewer bacteria in their midguts compared to all higher diet abundance treatments. Larval diet amount also had a significant impact on microbiota composition, primarily within larval breeding water and larvae. Increasing diet correlated with increased relative levels of Enterobacteriaceae and Flavobacteriaceae and decreased relative levels of Sphingomonadaceae. Multiple individual OTUs were significantly impacted by diet including one mapping to the genus Cedecea, which increased with higher diet amounts. This was consistent across all sample types, including sugar fed and blood fed adults. Taken together, these data suggest that availability of diet during development can cause lasting shifts in the size and composition of the microbiota in the disease vector Aedes aegypti.

Larvicidal Effect of Some Selected Salts Against the Dengue Vector Mosquito, Aedes aegypti (Diptera: Culicidae) in Bangladesh

2020 ◽  
Author(s):  
Mohammad Zaglul Haider Iqbal ◽  
Kabirul Bashar ◽  
Abdul Jabber Hawlader
Keyword(s):  
Aedes Aegypti ◽  
Larval Mortality ◽  
Aquatic Toxicity ◽  
Dengue Shock Syndrome ◽  
Adult Emergence ◽  
Hemorrhagic Fever ◽  
Larval Food ◽  
Larvicidal Effect ◽  
Vector Mosquito ◽  
Good Potential

Abstract Background The container breeding mosquito, Aedes aegypti is the major universal vector of dengue viruses capable of causing dengue fever (DF), dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). Vector control may have a potential role in reducing the morbidity and mortality of human by DHF/DSS. The purposes of this work were to evaluate the larvicidal effect of some salt solutions against the larvae of Ae. aegypti.Methods Freshly collected larvae were transferred to the laboratory and reared using rainwater as a rearing medium with yeast granules as larval food. Five salts i.e. AgNO3, HgCl2, CdCl2, CuSO4, and CuCl2 were tested to assess the larvicidal effect on both the 1st and 3rd instars larvae of Ae. aegypti. Serial concentrations (0, 1, 3, 5, 7 &10 ppm) of each salt were prepared by using distilled water as the solvent.Results Silver nitrate (AgNO3) was noted as the most effective larvicide followed by HgCl2, CdCl2, CuSO4 and CuCl2 against Ae. aegypti larvae. The LC50 of AgNO3 against 1st and 3rd instars larvae were 0.118 and 1.659 ppm, and the LC90 were 2 and 3.347 ppm, respectively. The LT50 of AgNO3(1 ppm) against 1st and 3rd instars larvae were 0.575 and 30.42hrs, and the LT90 was 6 and 67.49 hrs, respectively. All of the first instar larvae were killed and failed to pupate with every salt of each concentration (1–10 ppm) within 7 days. Whereas 3rd instar larvae were also unable to pupate entirely in AgNO3 and HgCl2 solutions but very few (5-36.66%) pupation was found at 7 ppm & higher concentrations of CdCl2, CuSo4, and CuCl2 salts. CdCl2, CuSo4 and CuCl2 prevented 66.66%, 57.14% and 50% adult emergences from pupae at 5 ppm concentration respectively. The order of decrease of toxicity for larval mortality was AgNO3 > HgCl2 > CdCl2 > CuSO4 > CuCl2 and for prevention of pupation & adult emergence was AgNO3 ≥ HgCl2 > CdCl2 > CuSO4 > CuCl2.Conclusions AgNO3 was found as a very good potential in the killing of Aedes aegypti larvae, prevention of pupae formation and adult emergence. Therefore, the results obtained could be considered a contribution to the search for eco-friendly larvicides of natural origin. Further studies are needed to understand the residual aquatic toxicity of this salt in the field.

scholarly journals Calculating the survival rate and estimated population density of gravid Aedes aegypti (Diptera, Culicidae) in Rio de Janeiro, Brazil

2008 ◽  
Vol 24 (12) ◽  
pp. 2747-2754 ◽  
Author(s):  
Rafael Maciel-de-Freitas ◽  
Álvaro E. Eiras ◽  
Ricardo Lourenço-de-Oliveira
Keyword(s):  
Survival Rate ◽  
Aedes Aegypti ◽  
Population Size ◽  
Rio De Janeiro ◽  
Gravid Female ◽  
Survival Rates ◽  
Vectorial Capacity ◽  
Basic Reproductive Number ◽  
Reproductive Number ◽  
Female Population

Population size and daily survival rates of disease vectors are important determinants of vectorial capacity. A mark-release-recapture experiment was conducted in a dengue endemic urban neighborhood of Rio de Janeiro, Brazil, to estimate population size, survival rate and vectorial capacity of Aedes aegypti females using back-pack aspirators and gravid sticky traps (MosquiTRAP). Estimations of the gravid female population size were different when using data gathered from just the MosquiTRAP (3,505 individuals) or aspirator (1,470). However Ae. aegypti survival rates and longevity were similar irrespective of the method of capture. Up to 26.3% of released females would be able to survive for more than 10 days, the length of time of the extrinsic incubation period. Vectorial capacity value ranged between 0.01567 and 0.4215 and the basic reproductive number (R0) was estimated to be between 0.0695 and 1.88.

scholarly journals Permethrin Resistance in Aedes aegypti Affects Aspects of Vectorial Capacity

Insects ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 71
Author(s):  
Tse-Yu Chen ◽  
Chelsea T. Smartt ◽  
Dongyoung Shin
Keyword(s):  
Aedes Aegypti ◽  
Sodium Channel ◽  
Mosquito Control ◽  
Vector Competence ◽  
Vectorial Capacity ◽  
Parental Population ◽  
Control Programs ◽  
Channel Gene ◽  
Sodium Channel Gene ◽  
Specific Pcr

Aedes aegypti, as one of the vectors transmitting several arboviruses, is the main target in mosquito control programs. Permethrin is used to control mosquitoes and Aedes aegypti get exposed due to its overuse and are now resistant. The increasing percentage of permethrin resistant Aedes aegypti has become an important issue around the world and the potential influence on vectorial capacity needs to be studied. Here we selected a permethrin resistant (p-s) Aedes aegypti population from a wild Florida population and confirmed the resistance ratio to its parental population. We used allele-specific PCR genotyping of the V1016I and F1534C sites in the sodium channel gene to map mutations responsible for the resistance. Two important factors, survival rate and vector competence, that impact vectorial capacity were checked. Results indicated the p-s population had 20 times more resistance to permethrin based on LD50 compared to the parental population. In the genotyping study, the p-s population had more homozygous mutations in both mutant sites of the sodium channel gene. The p-s adults survived longer and had a higher dissemination rate for dengue virus than the parental population. These results suggest that highly permethrin resistant Aedes aegypti populations might affect the vectorial capacity, moreover, resistance increased the survival time and vector competence, which should be of concern in areas where permethrin is applied.

scholarly journals Removal of Cyanide-Contaminated Water by Vetiver Grasses

2015 ◽  
Vol 9 (13) ◽  
pp. 252 ◽  
Author(s):  
Piyada Wachirawongsakorn ◽  
Tongsai Jamnongkan ◽  
Mohd Talib Latif
Keyword(s):  
Growth Rate ◽  
Survival Rate ◽  
Sri Lanka ◽  
Removal Efficiency ◽  
Water Samples ◽  
Low Cost ◽  
Contaminated Water ◽  
Vetiver Grass ◽  
Vetiveria Zizanioides ◽  
Concentration Levels

<p>Vetiver grass and it usages have been widely investigated in many researches as the preferred plant species due to its known efficiency, low cost, the ease of availability and spread. This research aimed to use four different vetiver grass (<em>Vetiveria zizanioides</em>) ecotypes to remove cyanide (CN<sup>-</sup>)-contaminated water for improve its quality. Growth capability, tolerance and removal efficiency were evaluated. The results showed that the vetiver grass had a 100% survival rate for one month after planting. Songkhlar3 had the longest leaves, followed by Surat-Thani, Sri Lanka and Monto, respectively. Root lengths of all ecotypes showed no significant differences (p ≤ 0.05). All vetiver grass ecotypes could potentially purify CN<sup>-</sup>-contaminated water at lower concentrations of ≤ 35 mg CN<sup>-</sup>/L. The Monto ecotype had the highest CN<sup>-</sup> removal efficiency at all CN<sup>-</sup> concentration levels, showing 100% CN<sup>-</sup> removal from the 5-45 mg CN<sup>-</sup>/L contaminated water samples within 2-5 weeks growth. The tolerance of vetiver grass to CN<sup>-</sup> was a more important factor than growth rate when selecting a vetiver grass ecotype for CN<sup>-</sup> phytoremediation.</p>

scholarly journals Corrigendum to “Larvicidal Potential of Five Selected Dragonfly Nymphs in Sri Lanka over Aedes aegypti (Linnaeus) Larvae under Laboratory Settings”

2019 ◽  
Vol 2019 ◽  
pp. 1-1
Author(s):  
Chathurika Samanmali ◽  
Lahiru Udayanga ◽  
Tharaka Ranathunge ◽  
Sandun J. Perera ◽  
Menaka Hapugoda ◽  
...  
Keyword(s):  
Sri Lanka ◽  
Aedes Aegypti ◽  
Dragonfly Nymphs
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