Determinants of genetic structure of the Sub-Saharan parasitic wasp Cotesia sesamiae

2017 ◽  
Author(s):  
Antoine Branca ◽  
Bruno Le Ru ◽  
Paul-André Calatayud ◽  
Julius Obonyo ◽  
Boaz Muzyoka ◽  
...  
Keyword(s):  
Biological Control ◽  
Life History ◽  
Genetic Structure ◽  
Parasitic Wasp ◽  
Sub Saharan Africa ◽  
Host Specialization ◽  
Life History Strategies ◽  
Cotesia Sesamiae ◽  
Sub Saharan ◽  
Different Strains

AbstractParasitoid life style represents one of the most diversified life history strategies on earth. There are however very few studies on the variables associated with intraspecific diversity of parasitoid insects, especially regarding the relationship with spatial, biotic and abiotic ecological factors. Cotesia sesamiae is a Sub-Saharan stenophagous parasitic wasp that parasitizes several African stemborer species with variable developmental success. The different host-specialized populations are infected with different strains of Wolbachia, an endosymbiotic bacterium widespread in arthropods that is known for impacting life history traits notably reproduction, and consequently species distribution. In this study, first we analyzed the genetic structure of C. sesamiae across Sub-Saharan Africa, using 8 microsatellite markers, and 3 clustering software. We identified five major population clusters across Sub-Saharan Africa, which probably originated in East African Rift region and expanded throughout Africa in relation to host genus and abiotic factors such as climatic classifications. Using laboratory lines, we estimated the incompatibility between the different strains of Wolbachia infecting C. sesamiae. We observed an incompatibility between Wolbachia strains was asymmetric; expressed in one direction only. Based on these results, we assessed the relationships between direction of gene flow and Wolbachia infections in the genetic clusters. We found that Wolbachia-induced reproductive incompatibility was less influential than host specialization in the genetic structure. Both Wolbachia and host were more influential than geography and current climatic conditions. These results are discussed in the context of African biogeography, and co-evolution between Wolbachia, virus parasitoid and host, in the perspective of improving biological control efficiency through a better knowledge of the biodiversity of biological control agents.

scholarly journals Biological Control of a Phytosanitary Pest (Thaumatotibia leucotreta): A Case Study

2021 ◽  
Vol 18 (3) ◽  
pp. 1198
Author(s):  
Sean D. Moore
Keyword(s):  
Biological Control ◽  
Systems Approach ◽  
Microbial Control ◽  
Codling Moth ◽  
Environmental Safety ◽  
Control Measures ◽  
Sub Saharan Africa ◽  
The European Union ◽  
Thaumatotibia Leucotreta ◽  
Sub Saharan

Thaumatotibia leucotreta, known as the false codling moth, is a pest of citrus and other crops in sub-Saharan Africa. As it is endemic to this region and as South Africa exports most of its citrus around the world, T. leucotreta has phytosanitary status for most markets. This means that there is zero tolerance for any infestation with live larvae in the market. Consequently, control measures prior to exporting must be exemplary. Certain markets require a standalone postharvest disinfestation treatment for T. leucotreta. However, the European Union accepts a systems approach, consisting of three measures and numerous components within these measures. Although effective preharvest control measures are important under all circumstances, they are most critical where a standalone postharvest disinfestation treatment is not applied, such as within a systems approach. Conventional wisdom may lead a belief that effective chemical control tools are imperative to achieve this end. However, we demonstrate that it is possible to effectively control T. leucotreta to a level acceptable for a phytosanitary market, using only biological control tools. This includes parasitoids, predators, microbial control, semiochemicals, and sterile insects. Simultaneously, on-farm and environmental safety is improved and compliance with the increasing stringency of chemical residue requirements imposed by markets is achieved.

scholarly journals Fine scale human genetic structure in three regions of Cameroon reveals episodic diversifying selection

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kevin K. Esoh ◽  
Tobias O. Apinjoh ◽  
Steven G. Nyanjom ◽  
Ambroise Wonkam ◽  
Emile R. Chimusa ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Ethnic Groups ◽  
Genetic Association ◽  
Association Studies ◽  
Genetic Association Studies ◽  
Genomic Region ◽  
Sub Saharan Africa ◽  
Genome Wide Association Studies ◽  
Fine Scale ◽  
Sub Saharan

AbstractInferences from genetic association studies rely largely on the definition and description of the underlying populations that highlight their genetic similarities and differences. The clustering of human populations into subgroups (population structure) can significantly confound disease associations. This study investigated the fine-scale genetic structure within Cameroon that may underlie disparities observed with Cameroonian ethnicities in malaria genome-wide association studies in sub-Saharan Africa. Genotype data of 1073 individuals from three regions and three ethnic groups in Cameroon were analyzed using measures of genetic proximity to ascertain fine-scale genetic structure. Model-based clustering revealed distinct ancestral proportions among the Bantu, Semi-Bantu and Foulbe ethnic groups, while haplotype-based coancestry estimation revealed possible longstanding and ongoing sympatric differentiation among individuals of the Foulbe ethnic group, and their Bantu and Semi-Bantu counterparts. A genome scan found strong selection signatures in the HLA gene region, confirming longstanding knowledge of natural selection on this genomic region in African populations following immense disease pressure. Signatures of selection were also observed in the HBB gene cluster, a genomic region known to be under strong balancing selection in sub-Saharan Africa due to its co-evolution with malaria. This study further supports the role of evolution in shaping genomes of Cameroonian populations and reveals fine-scale hierarchical structure among and within Cameroonian ethnicities that may impact genetic association studies in the country.

Biological control of gramineous lepidopteran stem borers in sub-Saharan Africa.

2009 ◽  
pp. 131-144
Author(s):  
W. A. Overholt ◽  
D. E. Conlong ◽  
R. Kfir ◽  
F. Schulthess ◽  
M. Sétamou
Keyword(s):  
Biological Control ◽  
Sub Saharan Africa ◽  
Stem Borers ◽  
Sub Saharan

scholarly journals Three arenaviruses in three subspecific natal multimammate mouse taxa in Tanzania: same host specificity, but different spatial genetic structure?

2020 ◽  
Vol 6 (2) ◽  
Author(s):  
Laura N Cuypers ◽  
Stuart J E Baird ◽  
Alexandra Hánová ◽  
Tatjana Locus ◽  
Abdul S Katakweba ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Spatial Genetic Structure ◽  
First Record ◽  
Sub Saharan Africa ◽  
Lassa Virus ◽  
Large Area ◽  
Order Of Magnitude ◽  
Morogoro Virus ◽  
Test Specificity ◽  
Sub Saharan

Abstract Mastomys natalensis is widespread in sub-Saharan Africa and hosts several arenavirus species, including the pathogenic zoonotic Lassa virus in West Africa. Mitochondrial lineages sub-divide the range of M. natalensis and have been associated with cryptic structure within the species. To test specificity of arenaviruses to hosts carrying these lineages, we screened 1772 M. natalensis in a large area of Tanzania where three mitochondrial lineages meet. We detected fifty-two individuals that were positive for one of three arenaviruses: Gairo, Morogoro, and Luna virus. This is the first record of Luna virus in Tanzania. We confirmed the specificity of each arenavirus to a distinct host mitochondrial lineage except for three cases in one locality at the centre of a host hybrid zone. No arenaviruses were detected in a large part of the study area. Morogoro and Gairo virus showed differences in prevalence (Morogoro virus lower than Gairo virus) and in genetic structure (Morogoro virus more structured than Gairo virus). However, both viruses have genetic neighbourhood size estimates of the same order of magnitude as Lassa virus. While differences in arenavirus and/or host evolutionary and ecological dynamics may exist, Tanzanian arenaviruses could be suited to model Lassa virus dynamics in M. natalensis.

scholarly journals Life History of the Golden Puddle Frog, Phrynobatrachus auritus Boulenger 1900 (Anura: Phrynobatrachidae)

2016 ◽  
Vol 8 (3) ◽  
pp. 77
Author(s):  
Geraud Canis Tasse Taboue ◽  
Eric Bertrand Fokam
Keyword(s):  
Life History ◽  
Development Time ◽  
Captive Breeding ◽  
Sub Saharan Africa ◽  
Advertisement Call ◽  
Calling Behaviour ◽  
Number Of Factors ◽  
History Of ◽  
Sub Saharan

Frogs of the genus <em>Phrynobatrachus </em>Günther, 1862 are endemic to sub-Saharan Africa. These are increasingly threatened by a number of factors and are believed to be declining. We report on captive breeding experiments involving <em>Phrynobatrachus auritus</em> Boulenger, 1900. We provide a comprehensive life history for this frog with emphasize on tadpole development time, as well as a description of both the advertisement call and calling behaviour of the adult.

scholarly journals Spatially varying selection shapes life history clines among populations of Drosophila melanogaster from sub-Saharan Africa

2015 ◽  
Vol 28 (4) ◽  
pp. 826-840 ◽  
Author(s):  
D. K. Fabian ◽  
J. B. Lack ◽  
V. Mathur ◽  
C. Schlötterer ◽  
P. S. Schmidt ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Life History ◽  
Sub Saharan Africa ◽  
Sub Saharan ◽  
Spatially Varying ◽  
Spatially Varying Selection

scholarly journals Biological control of aflatoxins in Africa: current status and potential challenges in the face of climate change

2016 ◽  
Vol 9 (5) ◽  
pp. 771-789 ◽  
Author(s):  
R. Bandyopadhyay ◽  
A. Ortega-Beltran ◽  
A. Akande ◽  
C. Mutegi ◽  
J. Atehnkeng ◽  
...  
Keyword(s):  
Climate Change ◽  
Biological Control ◽  
Value Chain ◽  
Large Scale ◽  
Aflatoxin Contamination ◽  
Sub Saharan Africa ◽  
Current Status ◽  
Health Food ◽  
Carrier Distribution ◽  
Sub Saharan

Aflatoxin contamination of crops is frequent in warm regions across the globe, including large areas in sub-Saharan Africa. Crop contamination with these dangerous toxins transcends health, food security, and trade sectors. It cuts across the value chain, affecting farmers, traders, markets, and finally consumers. Diverse fungi within Aspergillus section Flavi contaminate crops with aflatoxins. Within these Aspergillus communities, several genotypes are not capable of producing aflatoxins (atoxigenic). Carefully selected atoxigenic genotypes in biological control (biocontrol) formulations efficiently reduce aflatoxin contamination of crops when applied prior to flowering in the field. This safe and environmentally friendly, effective technology was pioneered in the US, where well over a million acres of susceptible crops are treated annually. The technology has been improved for use in sub-Saharan Africa, where efforts are under way to develop biocontrol products, under the trade name Aflasafe, for 11 African nations. The number of participating nations is expected to increase. In parallel, state of the art technology has been developed for large-scale inexpensive manufacture of Aflasafe products under the conditions present in many African nations. Results to date indicate that all Aflasafe products, registered and under experimental use, reduce aflatoxin concentrations in treated crops by >80% in comparison to untreated crops in both field and storage conditions. Benefits of aflatoxin biocontrol technologies are discussed along with potential challenges, including climate change, likely to be faced during the scaling-up of Aflasafe products. Lastly, we respond to several apprehensions expressed in the literature about the use of atoxigenic genotypes in biocontrol formulations. These responses relate to the following apprehensions: sorghum as carrier, distribution costs, aflatoxin-conscious markets, efficacy during drought, post-harvest benefits, risk of allergies and/or aspergillosis, influence of Aflasafe on other mycotoxins and on soil microenvironment, dynamics of Aspergillus genotypes, and recombination between atoxigenic and toxigenic genotypes in natural conditions.

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