scholarly journals Bulk‐up synchronization of successive larval cohorts of Anopheles gambiae and Anopheles coluzzii through temperature reduction at early larval stages: effect on emergence rate, body size and mating success

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Qaswa Zubair ◽  
Holly Matthews ◽  
Seynabou Sougoufara ◽  
Fatima Mujeeb ◽  
Simon Ashall ◽  
...  
Keyword(s):  
Body Size ◽  
Anopheles Gambiae ◽  
Mating Success ◽  
Mass Rearing ◽  
Alternative Methods ◽  
Mosquito Vector ◽  
Anopheles Coluzzii ◽  
Simple Method ◽  
Cooling Period ◽  
Larval Stages

Abstract Background Malaria persists as a huge medical and economic burden. Although the number of cases and death rates have reduced in recent years, novel interventions are a necessity if such gains are to be maintained. Alternative methods to target mosquito vector populations that involve the release of large numbers genetically modified mosquitoes are in development. However, their successful introduction will require innovative strategies to bulk-up mosquito numbers and improve mass rearing protocols for Anopheles mosquitoes. Methods The relationship between mosquito aquatic stage development and temperature was exploited so that multiple cohorts of mosquitoes, from separate egg batches, could be synchronized to ‘bulk-up’ the number of mosquitoes released. First instar larvae were separated into two cohorts: the first, maintained under standard insectary conditions at 27oC, the second subjected to an initial 5-day cooling period at 19oC. Results Cooling of 1st instars slowed the mean emergence times of Anopheles coluzzii and Anopheles gambiae by 2.4 and 3.5 days, respectively, compared to their 27oC counterparts. Pupation and emergence rates were good (> 85 %) in all conditions. Temperature adjustment had no effect on mosquito sex ratio and adult fitness parameters such as body size and mating success. Conclusions Bulk-up larval synchronization is a simple method allowing more operational flexibility in mosquito production towards mark-release-recapture studies and mass release interventions.

scholarly journals Bulk-up synchronization of successive larval cohorts of Anopheles gambiae and Anopheles coluzzii through temperature reduction at early larval stages: effect on emergence rates, body size and mating successss

2021 ◽  
Author(s):  
Qaswa Zubair ◽  
Holly Matthews ◽  
Seynabou Sougoufara ◽  
Fatima Mujeeb ◽  
Simon Ashall ◽  
...  
Keyword(s):  
Body Size ◽  
Anopheles Gambiae ◽  
Mass Rearing ◽  
Alternative Methods ◽  
Mosquito Vector ◽  
Anopheles Coluzzii ◽  
Simple Method ◽  
Cooling Period ◽  
Larval Stages ◽  
Fitness Parameters

Abstract Background Malaria persists as a huge medical and economic burden. Although the number of cases and death rates have reduced in recent years, novel interventions are a necessity if such gains are to be maintained. Alternative methods to target mosquito vector populations that involve the release of large numbers genetically modified mosquitoes are in development. However, their successful introduction will require innovative strategies to bulk-up mosquito numbers and improve mass rearing protocols for Anopheles mosquitoes.Methods The relationship between mosquito aquatic stage development and temperature was exploited so that multiple cohorts of mosquitoes, from separate egg batches, could be synchronized to ‘bulk-up’ the number of mosquitoes released. First instar larvae were separated into two cohorts: the first, maintained under standard insectary conditions at 27oC, the second subjected to an initial 5-day cooling period at 19oC. Results Cooling of 1st instars slowed the mean emergence times of Anopheles coluzzii and Anopheles gambiae by 2.4 and 3.5 days, respectively, compared to their 27oC counterparts. Pupation and emergence rates were good (> 85%) in all conditions. Temperature adjustment had no effect on mosquito sex ratio and adult fitness parameters such as body size and mating success were also comparable with the control cohort. Conclusions Bulk-up larval synchronization is a simple method allowing more operational flexibility in mosquito production towards mark-release-recapture studies and mass release interventions.

scholarly journals Bulk-up synchronisation of successive larval cohorts of Anopheles gambiae sensu stricto and Anopheles coluzzii through temperature reduction at early larval stages: effect on emergence rates, body size and mating success

2021 ◽  
Author(s):  
Qaswa Zubair ◽  
Holly Matthews ◽  
Seynabou Sougoufara ◽  
Fatima Mujeeb ◽  
Simon Ashall ◽  
...  
Keyword(s):  
Body Size ◽  
Mating Success ◽  
Mass Rearing ◽  
Sensu Stricto ◽  
Alternative Methods ◽  
Mosquito Vector ◽  
Anopheles Coluzzii ◽  
Simple Method ◽  
Cooling Period ◽  
Larval Stages

Abstract Background: Malaria persists as a huge medical and economic burden. Although the number of cases and death rates have reduced in recent years, novel interventions are a necessity if such gains are to be maintained. Alternative methods to target mosquito vector populations that involve the release of large numbers genetically modified mosquitoes are in development. However, their successful introduction will require innovative strategies to bulk-up mosquito numbers and improve mass rearing protocols for Anopheles mosquitoes. Methods: Here we aimed to exploit the relationship between mosquito aquatic stage development and temperature so that multiple cohorts of mosquitoes, from separate egg batches, could be synchronised for a ‘bulk-up’ of the number of mosquitoes released. First instar larvae were separated into two cohorts: the first, maintained under standard insectary conditions at 27 o C, the second subjected to an initial 5-day cooling period at 19 o C. Results: Cooling of 1 st instars slowed the mean emergence times of An. coluzzii and An. gambiae by 2.4 and 3.5 days, respectively, compared to their 27 o C counterparts. Pupation and emergence rates were good (> 85%) in all conditions. Temperature adjustment had no effect on mosquito sex ratio and adult fitness parameters such as body size and mating success were also comparable with the control cohort. Conclusions: Bulk-up larval synchronization is a simple method allowing more operational flexibility in mosquito production towards mark-release-recapture studies and mass release interventions.

scholarly journals Bulk-up Synchronisation of Successive Larval Cohorts of Anopheles Gambiae Sensu Stricto and Anopheles Coluzzii Through Temperature Reduction at Early Larval Stages: Effect on Emergence Rates, Body Size and Mating Success

2020 ◽  
Author(s):  
Qaswa Zubair ◽  
Holly Matthews ◽  
Seynabou Sougoufara ◽  
Fatima Mujeeb ◽  
Simon Ashall ◽  
...  
Keyword(s):  
Body Size ◽  
Mating Success ◽  
Mass Rearing ◽  
Sensu Stricto ◽  
Alternative Methods ◽  
Mosquito Vector ◽  
Anopheles Coluzzii ◽  
Simple Method ◽  
Cooling Period ◽  
Larval Stages

Abstract Background: Malaria persists as a huge medical and economic burden. Although the number of cases and death rates have reduced in recent years, novel interventions are a necessity if such gains are to be maintained. Alternative methods to target mosquito vector populations that involve the release of large numbers genetically modified mosquitoes are in development. However, their successful introduction will require innovative strategies to bulk-up mosquito numbers and improve mass rearing protocols for Anopheles mosquitoes.Methods: Here we aimed to exploit the relationship between mosquito aquatic stage development and temperature so that multiple cohorts of mosquitoes, from separate egg batches, could be synchronised for a ‘bulk-up’ of the number of mosquitoes released. First instar larvae were separated into two cohorts: the first, maintained under standard insectary conditions at 27oC, the second subjected to an initial 5-day cooling period at 19oC. Results: Cooling of 1st instars slowed the mean emergence times of An. coluzzii and An. gambiae by 2.4 and 3.5 days, respectively, compared to their 27oC counterparts. Pupation and emergence rates were good (> 85%) in all conditions. Temperature adjustment had no effect on mosquito sex ratio and adult fitness parameters such as body size and mating success were also comparable with the control cohort. Conclusions: Bulk-up larval synchronization is a simple method allowing more operational flexibility in mosquito production towards mark-release-recapture studies and mass release interventions.

Role of nutritional reserves and body size in Anopheles gambiae males mating success

Acta Tropica ◽  
2014 ◽  
Vol 132 ◽  
pp. S102-S107 ◽  
Author(s):  
Hamidou Maïga ◽  
Abdoulaye Niang ◽  
Simon P. Sawadogo ◽  
Roch K. Dabiré ◽  
Rosemary Susan Lees ◽  
...  
Keyword(s):  
Body Size ◽  
Anopheles Gambiae ◽  
Mating Success

scholarly journals Local adaptation and colonization are potential factors affecting sexual competitiveness and mating choice in Anopheles coluzzii populations

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Charles Nignan ◽  
Bèwadéyir Serge Poda ◽  
Simon Péguédwindé Sawadogo ◽  
Hamidou Maïga ◽  
Kounbobr Roch Dabiré ◽  
...  
Keyword(s):  
Local Adaptation ◽  
Mating Success ◽  
Mating Behaviour ◽  
Mass Rearing ◽  
Anopheles Coluzzii ◽  
Extrinsic Factors ◽  
Factors Affecting ◽  
Reproduction Biology ◽  
Potential Factors ◽  
Mating Choice

AbstractThe mating behaviour of the malaria vector Anopheles gambiae complex is an important aspect of its reproduction biology. The success of mosquito release programmes based on genetic control of malaria crucially depends on competitive mating between both laboratory-reared and wild individuals, and populations from different localities. It is known that intrinsic and extrinsic factors can influence the mating success. This study addressed some of the knowledge gaps about factors influcencing mosquito mating success. In semi-field conditions, the study compared the mating success of three laboratory-reared and wild allopatric An. coluzzii populations originating from ecologically different locations in Burkina Faso. Overall, it was found that colonization reduced the mating competitiveness of both males and females compared to that of wild type individuals. More importly, females were more likely to mate with males of their own population of origin, be it wild or colonised, suggesting that local adaptation affected mate choice. The observations of mating behaviour of colonized and local wild populations revealed that subtle differences in behaviour lead to significant levels of population-specific mating. This is the first study to highlight the importance of local adaptation in the mating success, thereby highlighting the importance of using local strains for mass-rearing and release of An. coluzzii in vector control programmes.

scholarly journals Laboratory and microcosm experiments reveal contrasted adaptive responses to ammonia and water mineralisation in aquatic stages of the sibling species Anopheles gambiae (sensu stricto) and Anopheles coluzzii

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Nwamaka Oluchukwu Akpodiete ◽  
Frédéric Tripet
Keyword(s):  
West Africa ◽  
Anopheles Gambiae ◽  
Emerging Adults ◽  
Sibling Species ◽  
Adult Emergence ◽  
Ecological Speciation ◽  
Sensu Stricto ◽  
Rice Fields ◽  
Anopheles Coluzzii ◽  
Phenotypic Quality

Abstract Background The sibling species of the malaria mosquito, Anopheles gambiae (sensu stricto) and Anopheles coluzzii co-exist in many parts of West Africa and are thought to have recently diverged through a process of ecological speciation with gene flow. Divergent larval ecological adaptations, resulting in Genotype-by-Environment (G × E) interactions, have been proposed as important drivers of speciation in these species. In West Africa, An. coluzzii tends to be associated with permanent man-made larval habitats such as irrigated rice fields, which are typically more eutrophic and mineral and ammonia-rich than the temporary rain pools exploited by An. gambiae (s.s.) Methods To highlight G × E interactions at the larval stage and their possible role in ecological speciation of these species, we first investigated the effect of exposure to ammonium hydroxide and water mineralisation on larval developmental success. Mosquito larvae were exposed to two water sources and increasing ammonia concentrations in small containers until adult emergence. In a second experiment, larval developmental success was compared across two contrasted microcosms to highlight G × E interactions under conditions such as those found in the natural environment. Results The first experiment revealed significant G × E interactions in developmental success and phenotypic quality for both species in response to increasing ammonia concentrations and water mineralisation. The An. coluzzii strain outperformed the An. gambiae (s.s.) strain under limited conditions that were closer to more eutrophic habitats. The second experiment revealed divergent crisscrossing reaction norms in the developmental success of the sibling species in the two contrasted larval environments. As expected, An. coluzzii had higher emergence rates in the rice paddy environment with emerging adults of superior phenotypic quality compared to An. gambiae (s.s.), and vice versa, in the rain puddle environment. Conclusions Evidence for such G × E interactions lends support to the hypothesis that divergent larval adaptations to the environmental conditions found in man-made habitats such as rice fields in An. coluzzii may have been an important driver of its ecological speciation.

scholarly journals Anopheles gambiae Genome Conservation as a Resource for Rational Gene Drive Target Site Selection

Insects ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 97
Author(s):  
Nace Kranjc ◽  
Andrea Crisanti ◽  
Tony Nolan ◽  
Federica Bernardini
Keyword(s):  
Anopheles Gambiae ◽  
Data Storage ◽  
Genomic Variation ◽  
Malaria Vectors ◽  
Anopheles Coluzzii ◽  
Structural Constraints ◽  
Gene Drive ◽  
Genetic Traits ◽  
A Genome ◽  
Insight Into

The increase in molecular tools for the genetic engineering of insect pests and disease vectors, such as Anopheles mosquitoes that transmit malaria, has led to an unprecedented investigation of the genomic landscape of these organisms. The understanding of genome variability in wild mosquito populations is of primary importance for vector control strategies. This is particularly the case for gene drive systems, which look to introduce genetic traits into a population by targeting specific genomic regions. Gene drive targets with functional or structural constraints are highly desirable as they are less likely to tolerate mutations that prevent targeting by the gene drive and consequent failure of the technology. In this study we describe a bioinformatic pipeline that allows the analysis of whole genome data for the identification of highly conserved regions that can point at potential functional or structural constraints. The analysis was conducted across the genomes of 22 insect species separated by more than hundred million years of evolution and includes the observed genomic variation within field caught samples of Anopheles gambiae and Anopheles coluzzii, the two most dominant malaria vectors. This study offers insight into the level of conservation at a genome-wide scale as well as at per base-pair resolution. The results of this analysis are gathered in a data storage system that allows for flexible extraction and bioinformatic manipulation. Furthermore, it represents a valuable resource that could provide insight into population structure and dynamics of the species in the complex and benefit the development and implementation of genetic strategies to tackle malaria.

scholarly journals The regulatory genome of the malaria vector Anopheles gambiae: integrating chromatin accessibility and gene expression

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
José L Ruiz ◽  
Lisa C Ranford-Cartwright ◽  
Elena Gómez-Díaz
Keyword(s):  
Gene Expression ◽  
Transcriptional Regulation ◽  
Anopheles Gambiae ◽  
Mosquito Control ◽  
Regulatory Elements ◽  
Chromatin Accessibility ◽  
Malaria Vectors ◽  
Specific Gene ◽  
Mosquito Vector ◽  
Human Malaria

Abstract Anopheles gambiae mosquitoes are primary human malaria vectors, but we know very little about their mechanisms of transcriptional regulation. We profiled chromatin accessibility by the assay for transposase-accessible chromatin by sequencing (ATAC-seq) in laboratory-reared A. gambiae mosquitoes experimentally infected with the human malaria parasite Plasmodium falciparum. By integrating ATAC-seq, RNA-seq and ChIP-seq data, we showed a positive correlation between accessibility at promoters and introns, gene expression and active histone marks. By comparing expression and chromatin structure patterns in different tissues, we were able to infer cis-regulatory elements controlling tissue-specific gene expression and to predict the in vivo binding sites of relevant transcription factors. The ATAC-seq assay also allowed the precise mapping of active regulatory regions, including novel transcription start sites and enhancers that were annotated to mosquito immune-related genes. Not only is this study important for advancing our understanding of mechanisms of transcriptional regulation in the mosquito vector of human malaria, but the information we produced also has great potential for developing new mosquito-control and anti-malaria strategies.

scholarly journals Effect of naturally occurring Wolbachia in Anopheles gambiae s.l. mosquitoes from Mali on Plasmodium falciparum malaria transmission

2017 ◽  
Vol 114 (47) ◽  
pp. 12566-12571 ◽  
Author(s):  
Fabio M. Gomes ◽  
Bretta L. Hixson ◽  
Miles D. W. Tyner ◽  
Jose Luis Ramirez ◽  
Gaspar E. Canepa ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Anopheles Gambiae ◽  
Malaria Transmission ◽  
Deleterious Effect ◽  
Plasmodium Falciparum Malaria ◽  
Anopheles Coluzzii ◽  
Naturally Occurring ◽  
Anopheles Gambiae S.L ◽  
Cat Fleas ◽  
Sporozoite Infection

A naturally occurring Wolbachia strain (wAnga-Mali) was identified in mosquitoes of the Anopheles gambiae complex collected in the Malian villages of Dangassa and Kenieroba. Phylogenetic analysis of the nucleotide sequence of two 16S rRNA regions showed that wAnga-Mali clusters with Wolbachia strains from supergroup A and has the highest homology to a Wolbachia strain isolated from cat fleas (Ctenocephalides). wAnga-Mali is different from two Wolbachia strains previously reported in A. gambiae from Burkina Faso (wAnga_VK5_STP and wAnga_VK5_3.1a). Quantitative analysis of Wolbachia and Plasmodium sporozoite infection in field-collected mosquitoes indicates that the prevalence and intensity of Plasmodium falciparum sporozoite infection is significantly lower in Wolbachia-infected females. The presence of Wolbachia in females from a laboratory Anopheles coluzzii (A. gambiae, M form) colony experimentally infected with P. falciparum (NF54 strain) gametocyte cultures slightly enhanced oocyst infection. However, Wolbachia infection significantly reduced the prevalence and intensity of sporozoite infection, as observed in the field. This indicates that wAnga-Mali infection does not limit early stages of Plasmodium infection in the mosquito, but it has a strong deleterious effect on sporozoites and reduces malaria transmission.

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