Гранитоиды обрамления Криворожской структуры. Проблемы корреляции геологических тел и комплексов

Current population genetic models fail to cope with genetic differentiation for species with large, contiguous and heterogeneous distribution. We show that in such a case, genetic differentiation can be predicted at equilibrium by circuit theory, where conductance corresponds to abundance in species distribution models (SDM). Circuit-SDM approach was used for the phylogeographic study of the lepidopteran cereal stemborer Busseola fusca Füller (Noctuidae) across sub-Saharan Africa. Species abundance was surveyed across its distribution range. SDM models were optimized and selected by cross validation. Relationship between observed matrices of genetic differentiation between individuals, and matrices of resistance distance was assessed through Mantel tests and redundancy discriminant analyses (RDA). A total of 628 individuals from 130 localities in 17 countries were genotyped at 7 microsatellite loci. Six population clusters were found based on a Bayesian analysis. The eastern margin of Dahomey Gap between East and West Africa was the main factor of genetic differentiation. The SDM projections at present, last interglacial and last glacial maximum periods were used for estimation of circuit resistance between locations of genotyped individuals. For all periods of time, when using either all individuals or only East-African individuals, partial Mantel r and RDA analyses conditioning on geographic distance were found significant. Under future projections (year 2080), partial r and RDA significance were different. From this study, it is concluded that analytical solutions provided by circuit theory are useful for the evolutionary management of populations and for phylogeographic analysis when coalescence times are not accessible by approximate Bayesian simulations

Blood feeding behaviour comparison and contribution of Anopheles coluzzii and Anopheles gambiae, two sibling species living in sympatry, to malaria transmission in Alibori and Donga region, northern Benin, West Africa

Background: The main goal of this study was to assess the blood feeding behaviour and the contribution Anopheles coluzzii and Anopheles gambiae, 2 sibling species of An. gambiae sensu stricto. present and living in sympatry in 2 regions of northern Benin targeted for indoor residual spraying (IRS).Methods: The study was carried out in 6 districts of 2 regions of Benin (Alibori and Donga). Human landing catches (HLC) performed inside and outside of the households and pyrethrum spray captures (PSC) carried out in bedrooms were used to sample vector populations (An. gambiae and An. coluzzii). Collected mosquitoes were analysed to esti-mate the human biting rate indoors and outdoors, the circumsporozoite antigen positivity, and the anthropophagic index using ELISA methodology. Polymerase chain reaction was used to estimate the frequency of the knockdown resistance (kdr) L1014F and the ace-1 mutations, 2 markers associated respectively with pyrethroids and carbamate/organophosphate insecticide resistance.Results: A higher blood feeding rate was observed in An. gambiae compared to An. coluzzii as well as, a non-pro-nounced outdoor biting behavior in both species. The latter showed similar anthropophagic and sporozoite rates. However the analysis indicates a seasonal difference in the contribution of each species to malaria transmission associated with shifts in resting behaviour. Anopheles coluzzii females accounted for most of the detected infections: 86% in Alibori and 79% in Donga, during the dry season versus 14.4% and 21.2%, respectively for An. gambiae during the same period. This relationship was reversed in Donga during the rainy season (66% for An. gambiae against 34% for An. coluzzii). Results also indicated lower frequencies of kdr L1014F and ace-1 in An. coluzzii versus An. gambiae.Conclusion: Despite similarity in some parameters related to malaria transmission in both surveyed species, An. coluzzii is potentially a more important malaria vector because of high density in the region. It is also charac-terized by lower frequencies of the ace-1 mutation than is An. gambiae. The ongoing use of pirimiphos methyl (organophosphate) for IRS should continue to show a good impact in Alibori and Donga because of the very low level of the ace-1 mutation in both species

Impact of three years of large scale Indoor Residual Spraying (IRS) and Insecticide Treated Nets (ITNs) interventions on insecticide resistance in Anopheles gambiae s.l. in Benin

<p>Abstract</p> <p>Background</p> <p>In Benin, Indoor Residual Spraying (IRS) and long-lasting insecticidal nets (LLINs) are the cornerstones of malaria prevention. In the context of high resistance of <it>Anopheles gambiae </it>to pyrethroids, The National Malaria Control Program (NMCP) has undertaken a full coverage of IRS in a no-flood zone in the Oueme region, coupled with the distribution of LLINs in a flood zone. We assessed the impact of this campaign on phenotypic resistance, <it>kdr </it>(knock-down resistance) and <it>ace-1^R</it>(insensitive acetylcholinesterase) mutations.</p> <p>Methods</p> <p>Insecticides used for malaria vector control interventions were bendiocarb WP (0.4 g/m²) and deltamethrin (55 mg/m²), respectively for IRS and LLINs. Susceptibility status of <it>An. gambiae </it>was assessed using World Health Organization bioassay tests to DDT, permethrin, deltamethrin and bendiocarb in the Oueme region before intervention (2007) and after interventions in 2008 and 2010. <it>An. gambiae </it>specimens were screened for identification of species, molecular M and S forms and for the detection of the West African <it>kdr </it>(L1014F) as well as <it>ace-1^R</it>mutations using PCR techniques.</p> <p>Results</p> <p>The univariate logistic regression performed showed that <it>kdr </it>frequency has increased significantly during the three years in the intervention area and in the control area. Several factors (LLINs, IRS, mosquito coils, aerosols, use of pesticides for crop protection) could explain the selection of individual resistant <it>An. gambiae</it>. The <it>Kdr </it>resistance gene could not be the only mechanism of resistance observed in the Oueme region. The high susceptibility to bendiocarb is in agreement with a previous study conducted in Benin. However, the occurrence of <it>ace-1^R</it>heterozygous individuals even on sites far from IRS areas, suggests other factors may contribute to the selection of resistance other than those exerted by the vector control program.</p> <p>Conclusion</p> <p>The results of this study have confirmed that <it>An.gambiae </it>have maintained and developed the resistance to pyrethroids, but are still susceptible to bendiocarb. Our data clearly shows that selection of resistant individuals was caused by other insecticides than those used by the IRS and LLINs.</p

Phylogéographie et génétique des populations du foreur de tiges de céréales Busseola fusca (Fuller) (Lepidoptera, Noctuidae) en Afrique subsaharienne (implications pour la lutte biologique contre cet insecte)

Busseola fusca (Fuller) (Lepidoptera, Noctuidae) est un ravageur majeur du maïs et du sorgho cultivé en Afrique Subsaharienne. Des différences observées dans les traits de vie et l'écologie de l'espèce entre les populations Est et Ouest africaines suggèrent l'existence de populations génétiquement différenciées selon la géographie ou les types de biotopes. Le rôle des plantes hôtes, et notamment celui des deux principales plantes cultivées consommées par l'insecte, dans l'éventuelle structuration génétique de ses populations est à déterminer. Une vaste étude phylogéographique basée sur l'utilisation d'un marqueur mitochondrial, le cytochrome b et sur l'analyse de nombreux échantillons (590 individus provenant de 112 localités incluant la majeure partie de l'aire de distribution de foreur), a été réalisée. Cette étude a révélé l'existence de trois clades principaux d'haplotypes (W, KI, KII) correspondant à des populations isolées à l'Ouest et à l'Est de l'Afrique au Pléistocène, il y a environ un million d'années. Le clade W localisé en Afrique de l'Ouest est isolé géographiquement des clades KI et KII qui sont partiellement sympatriques. Le clade KI voit sa distribution limitée à une partie de l'Afrique de l'Est alors que le clade KII présente une large distribution géographique couvrant l'Est, le Centre et le Sud de l'Afrique Subsaharienne. Les résultats des analyses phylogénétiques, les paramètres démographiques calculés, les statistiques de Wright ainsi que les analyses des clades emboîtés confirment que ces trois populations, après avoir été isolées dans des aires refuges différentes, ont connu une expansion démographique et géographique, même si les populations locales sont caractérisées par des phénomènes de restriction des flux géniques avec isolement par la distance. L'analyse de mismatch distribution et les valeurs négative de l'indice D de Tajima sont en accord avec l'hypothèse d'une expansion démographique des trois clades. Des différenciations génétiques significatives ont été mises en évidence à différents niveaux hiérarchiques par l'analyse moléculaire de la variance (AMOVA). La Ligne Volcanique du Cameroun et la Rift Valley seraient deux des facteurs qui ont modelé la structure génétique des populations de B. fusca. La plus grande diversité haplotypique et nucléotidique de B. fusca dans les régions ghanéenne (clade W), érythréenne (clade KI) et kenyane (clade KII) a permis de les identifier comme les centres probables d'origine géographique de chaque clade. L'histoire génétique des populations de B. fusca, telle que révélée par l'analyse du génome mitochondrial, apparaît indépendante de la domestication du sorgho et de l'introduction et de l'expansion des cultures de maïs. L'ancienne structure génétique est maintenue à travers les différentes époques avec un passage récurrent et local des individus de B. fusca des plantes hôtes sauvages aux cultivées. Un parallèle original a pu être fait entre les résultats de l'étude phylogéographique de cet insecte graminivore et ceux de plusieurs études portant sur des mammifères herbivores africains. Cette analyse parallèle montre que des facteurs paléo-climatiques similaires ont probablement modelé les populations des animaux de groupes éloignés associés aux milieux graminéens africains.Busseola fusca (Fuller) (Lepidoptera, Noctuidae) is a major pest of maize and cultivated sorghum in sub-Saharan Africa. The observed difference in the life features and the ecology of species among East and West African populations suggest the existence of populations genetically differentiated in accordance with the geography or biotope types. The role of host plant, particularly that related to two major cultivated plant consumed by insect, in possible of genetic structure of its populations is being established. A large phylogeographic study based on use of one mitochondrial marker, the cytochrome b and on analysis of numerous samplings (590 individuals from 112 localities including the major part of the spatial distribution of borer) has been performed. This study has showed the presence of three main haplotype clades (W, KI, KII) corresponding to populations isolated in West and East Africa in Pleistocene, around one million years ago. Clade W localized in West Africa split geographically from clade KI and clade KII that are partially sympatric. Clade KI is limited to one part of East Africa whereas clade KII shows a large geographical distribution covering well East, Central and Southern sub-Saharan Africa. Phylogenetic, F-statistics, calculated demographic parameters and nested clade phylogeographic analyses results confirmed that the clades, after their isolation in three different refuge areas, experienced geographic and demographic expansion even if local populations were characterized by the phenomena of restricted gene flow with isolation by distance. Mismatch distribution analysis and the negative values of Tajima D index are consistent with a demographic expansion hypothesis of three clades. Significant genetic differentiations have been highlighted at various hierarchical levels by analysis of molecular variance (AMOVA). The Cameroon Volcanic Line and the Rift Valley appear to be two factors contributing to the genetic structure of B. fusca populations. The highest haplotype and nucleotide diversity in Ghanaian (clade W), Eritrean (clade KI) and Kenyan (clade KII) regions has allowed identifying them as the likelihood geographic centres of origin of each clade. The population genetic history of B. fusca as revealed by mitochondrial genome analysis appears independent to sorghum domestication and introduction and expansion of maize. The ancient genetic structure is maintained through different periods with recurrent and local shift of B. fusca individuals from wild host plants to cultivated. An original parallel has been able to be performed with the results of phylogeographic study of this graminaceous insect and all those of many studies related on African mammalian herbivorous. This parallel analysis indicates that similar paleoclimatic factors have likely shaped animal populations from distant groups associated with African graminaceous environments.ORSAY-PARIS 11-BU Sciences (914712101) / SudocPARIS-Museum Hist.Naturelle (751052304) / SudocSudocFranceF

Decreased proportions of indoor feeding and endophily in <it>Anopheles gambiae s.l.</it> populations following the indoor residual spraying and insecticide-treated net interventions in Benin (West Africa)

Abstract Background In many parts of Africa as in Benin, the main strategies of vector control are based on the scaling-up of Long Lasting Insecticide Treated Nets (LLITNs) and indoor residual spraying (IRS). The need to understand the biological implications of IRS in large scale and full coverage of LLITNs is paramount. It is in this context that the present study was conducted. It aims to evaluate the effect of a large scale IRS using a non-pyrethroid insecticide and full coverage of deltamethrin treated nets on the behavior of An. gambiae s.l. in the intervention areas compared to untreated areas used as controls. Methods Mosquitoes were collected using human landing catches, pyrethrum spray catches and window exit traps to assess reduction of entry rate, endophily rate, endophagy rate and overall mortality rate in natural populations of An. gambiae s.l. before IRS and LLITNs intervention (2007) and after in 2008 and 2010. Results In the IRS arm, endophily rate was 67.13% before intervention and 4.5% after intervention, whereas in the control arm it was stable at 51.67% (P > 0 .05). In the LLITN arm endophily rates also decreased after intervention. After the IRS, no gravid mosquitoes were collected from all treated localities, but LLITN performance was not that spectacular. The proportion of mosquitoes biting indoors in the IRS arm decreased from 67.09% before intervention to 42.85% after intervention, compared to a low but significant decrease (71.31% to 57. 46%) in the LLITN arm. The use of vector control tools and behavior of the host would be the main factors that modify the behavior of taking a human blood meal observed on An. gambiae s.l. inside human dwellings. Conclusion The impact on the behavior of An. gambiae s.l. observed with the bendiocarb used in IRS was highly effective compared with the free distribution of LLITNs in terms of mortality and the decrease of proportions of indoor feeding. Despite this efficacy, there is a need for complementary tools and research of alternative strategy oriented on effective health education, and the use of powerful tools such as IRS, LLITNs, larviciding and repellents.</p

Phylogeography and population genetics of the maize stalk borer Busseola fusca (Lepidoptera, Noctuidae) in sub-Saharan Africa

The population genetics and phylogeography of African phytophagous insects have received little attention. Some, such as the maize stalk borer Busseola fusca, display significant geographic differences in ecological preferences that may be congruent with patterns of molecular variation. To test this, we collected 307 individuals of this species from maize and cultivated sorghum at 52 localities in West, Central and East Africa during the growing season. For all collected individuals, we sequenced a fragment of the mitochondrial cytochrome b. We tested hypotheses concerning the history and demographic structure of this species. Phylogenetic analyses and nested clade phylogeographic analyses (NCPA) separated the populations into three mitochondrial clades, one from West Africa, and two - Kenya I and Kenya II - from East and Central Africa. The similar nucleotide divergence between clades and nucleotide diversity within clades suggest that they became isolated at about the same time in three different refuges in sub-Saharan Africa and have similar demographic histories. The results of mismatch distribution analyses were consistent with the demographic expansion of these clades. Analysis of molecular variance (AMOVA) indicated a high level of geographic differentiation at different hierarchical levels. NCPA suggested that the observed distribution of haplotypes at several hierarchical levels within the three major clades is best accounted for by restricted gene flow with isolation by distance. The domestication of sorghum and the introduction of maize in Africa had no visible effect on the geographic patterns observed in the B. fusca mitochondrial genome

Phylogeny and systematics of the Acrapex apicestriata (Bethune-Baker, 1911) species complex (Lepidoptera, Noctuidae, Noctuinae, Apameini, Sesamiina) with the description of eight new species from the Afrotropics

International audienceTwelve morphologically similar species of Acrapex Hampson 1894, (Lepidoptera, Noctuidae, Noctuinae, Apameini, Sesamiina), from Western, Central and Eastern Africa are reviewed. Eight of these species are new to science and are described: Acrapex akunamatatan. sp. and A. incrassata n. sp. from Kenya; A. gracilis n. sp., A. iringa n. sp., A. lukumbura n. sp. and A. rungwe n. sp. from Tanzania; A. soyema n. sp. from Ethiopia; and A. zoutoi n. sp. from Benin. All 12 species belong to a species complex that we hereby define as the Acrapex apicestriata group. Host-plants for three of the new species are recorded: Setaria incrassata (Hochst.) Hack. for Acrapex incrassata; Cymbopogon pospishilii (K. Schum.) C.E. Hubb. for A. rungwe; and Andropogon perligulatus Stapf. for A. zoutoi. We also conducted molecular phylogenetic analyses (using maximum likelihood and Bayesian inference) on a six gene multimarker molecular dataset (four mitochondrial and two nuclear gene fragments; 4581 nucleotides in length) consisting of 15 Acrapex species (including seven species from the apicestriata group) and four outgroups species from the subtribe Sesamiina (from genera Busseola Thurau 1904, Sciomesa Tams & Bowden 1953, Pirateolea Moyal, Le Ru, Conlong, Cugala, Defabachew, Matama-Kauma, Pallangyo & Van den Berg 2010 and Sesamia Boisduval & Guenee 1852). Both maximum likelihood and Bayesian inference analyses yield a similar and well-supported topology, which supports the monophyly of the apicestriata group

Phylogeny and systematics of the Sesamia coniota Hampson species group (Lepidoptera: Noctuidae: Noctuinae: Apameini: Sesamiina), with the description of three new species from the Afrotropical region

In this study, we review six morphologically similar species of Sesamia Guenee, 1852 from Africa, including three new species that are described: Sesamia corymbosus Le Ru n. sp., S. schoenoplectus Le Ru n. sp. and S. temberma Le Ru n. sp. These six species belong to a species complex that we hereby define as the Sesamia coniota group. Host plants of four species are recorded: Schoenoplectus corymbosus (Roth ex Roem. & Schult.) J. Raynal. for S. corymbosus and S. schoenoplectus, Echinochloa pyramidalis (Lam.) Hitschc. & Chase, Eriochloa meyeriana (Nees) Pilg., Schoenoplectus corymbosus and Typha latifolia L. for S. jansei, Tams & Bowden, 1953 and Pennisetum sp. for S. temberma. We also conduct molecular phylogenetic analyses on a multimarker (four mitochondrial and two nuclear genes) molecular dataset encompassing 36 specimens (including 32 specimens belonging to the S. coniota group). Molecular analyses allow assessing the phylogenetic relationships of five out of six species of the group