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Articles 811 - 840 of 1443

Full-Text Articles in Life Sciences

Genetic Divergence Of Chikungunya Virus Plaque Variants From The Comoros Island (2005), Caroline Wasonga, Shingo Inoue, Cecilia Rumberia, George Michuki, James Kimotho, Juliette R. Ongus, Rosemary Sang, Lillian Musila Dec 2015

Genetic Divergence Of Chikungunya Virus Plaque Variants From The Comoros Island (2005), Caroline Wasonga, Shingo Inoue, Cecilia Rumberia, George Michuki, James Kimotho, Juliette R. Ongus, Rosemary Sang, Lillian Musila

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Chikungunya virus (CHIKV) from a human sample collected during the 2005 Chikungunya outbreak in the Comoros Island, showed distinct and reproducible large (L2) and small (S7) plaques which were characterized in this study. The parent strain and plaque variants were analysed by in vitro growth kinetics in different cell lines and their genetic similarity assessed by whole genome sequencing, comparative sequence alignment and phylogenetic analysis. In vitro growth kinetic assays showed similar growth patterns of both plaque variants in Vero cells but higher viral titres of S7 compared to L2 in C6/36 cells. Amino acids (AA) alignments of the CHIKV …

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Characteristics Of Soils In Selected Maize Growing Sites Along Altitudinal Gradients In East African Highlands, Elijah Njuguna, Mary Gathara, Stanley Nadir, Sizah Mwalusepo, David Williamson, Pierre Etienne Mathé, Jackson Kimani, Tobias Landmann, Gerald Juma, George Ong'amo, Erastus Gatebe, Bruno Le Ru, Paul André Calatayud Dec 2015

Characteristics Of Soils In Selected Maize Growing Sites Along Altitudinal Gradients In East African Highlands, Elijah Njuguna, Mary Gathara, Stanley Nadir, Sizah Mwalusepo, David Williamson, Pierre Etienne Mathé, Jackson Kimani, Tobias Landmann, Gerald Juma, George Ong'amo, Erastus Gatebe, Bruno Le Ru, Paul André Calatayud

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Maize is the main staple crop in the East African Mountains. Understanding how the edaphic characteristics change along altitudinal gradients is important for maximizing maize production in East African Highlands, which are the key maize production areas in the region. This study evaluated and compared the levels of some macro and micro-elements (Al, Ca, Fe, K, Mg, Mn, Na and P) and other soil parameters (pH, organic carbon content, soil texture [i.e. % Sand, % Clay and % Silt], cation exchange capacity [CEC], electric conductivity [EC], and water holding capacity [HC]). Soil samples were taken from maize plots along three …

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Discrete Davydov's Soliton In Α-Helical Protein Molecule With Anharmonic Hydrogen Bond And Thermal Noise, Frank T. Ndjomatchoua, Clément Tchawoua, Joël D.T. Tchinang, Bruno P. Lerü, Henri E.Z. Tonnang Dec 2015

Discrete Davydov's Soliton In Α-Helical Protein Molecule With Anharmonic Hydrogen Bond And Thermal Noise, Frank T. Ndjomatchoua, Clément Tchawoua, Joël D.T. Tchinang, Bruno P. Lerü, Henri E.Z. Tonnang

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An improvement of the Davydov's model for energy transfer in α-helix protein is proposed. Using hyperbolic cosine potential type to model hydrogen bond potential, we have obtained from the adiabatic approximation, a discrete nonlinear Schrödinger equation with inverse hyperbolic sine nonlinearity. Using the two-dimensional discrete map approach, we have found a linearly stable intrinsic localized mode of the corresponding developed equation. Mobility of the intrinsic localized mode was achieved by moving the local impurity hypothesized as the anomalous band energy. The reactivity of the discrete breather under thermal noise was studied numerically with the Langevin's approach. It was shown that …

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An Improved Odor Bait For Monitoring Populations Of Aedes Aegypti-Vectors Of Dengue And Chikungunya Viruses In Kenya, Eunice A. Owino, Rosemary Sang, Catherine L. Sole, Christian Pirk, Charles Mbogo, Baldwyn Torto Dec 2015

An Improved Odor Bait For Monitoring Populations Of Aedes Aegypti-Vectors Of Dengue And Chikungunya Viruses In Kenya, Eunice A. Owino, Rosemary Sang, Catherine L. Sole, Christian Pirk, Charles Mbogo, Baldwyn Torto

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Abstract Background: Effective surveillance and estimation of the biting fraction of Aedes aegypti is critical for accurate determination of the extent of virus transmission during outbreaks and inter-epidemic periods of dengue and chikungunya fever. Here, we describe the development and use of synthetic human odor baits for improved sampling of adult Ae. aegypti, in two dengue and chikungunya fevers endemic areas in Kenya; Kilifi and Busia counties. Methods: We collected volatiles from the feet and trunks of two female and two male volunteers aged between 25 and 45 years. We used coupled gas chromatography- electroantennographic detection (GC/EAD) analysis to screen …

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Olfactory Associative Learning In Two African Stingless Bee Species (Meliponula Ferruginea And M. Bocandei, Meliponini), J. Henske, K. Krausa, F. A. Hager, K. Nkoba, W. H. Kirchner Nov 2015

Olfactory Associative Learning In Two African Stingless Bee Species (Meliponula Ferruginea And M. Bocandei, Meliponini), J. Henske, K. Krausa, F. A. Hager, K. Nkoba, W. H. Kirchner

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Worldwide only a few of the more than 500 stingless bee species has been studied in any detail. Most studies on stingless bees have been conducted in the Neotropics, whereas a very few have been undertaken in Africa. Foraging success is dependent to a greater or lesser extent on olfactory cues or signals. A prerequisite to effective foraging via odors is that the bees are able to associate odors with a nectar reward and memorize this information. In the context of olfactory learning, only five species of stingless bees have been studied using classical conditioning of the proboscis extension reflex …

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A New Species Of Alhajarmyia Stuckenberg (Diptera: Vermileonidae), The First Wormlion Fly Described From East Africa And Its Biogeographical Implications, Vaughn R. Swart, Ashley H. Kirk-Spriggs, Robert S. Copeland Nov 2015

A New Species Of Alhajarmyia Stuckenberg (Diptera: Vermileonidae), The First Wormlion Fly Described From East Africa And Its Biogeographical Implications, Vaughn R. Swart, Ashley H. Kirk-Spriggs, Robert S. Copeland

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A second species of the genus Alhajarmyia Stuckenberg (A. stuckenbergi Swart, Kirk-Spriggs & Copeland, sp. n.), is described and figured, from the Eastern Arc Mountains of Kenya (Kasigau Mountain and Taita Hills), being the first vermileonid recorded from East Africa. The species is shown to differ from its congener, A. umbraticola (Stuckenberg & Fisher), described from Oman in the Arabian Peninsula, based on external characters including male and female terminalia. An identification key is provided together with distribution maps for the two species, and biogeographical aspects are discussed.

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Linalool Oxide: Generalist Plant Based Lure For Mosquito Disease Vectors, Vincent O. Nyasembe, David P. Tchouassi, Charles M. Mbogo, Catherine L. Sole, Christian Pirk, Baldwyn Torto Nov 2015

Linalool Oxide: Generalist Plant Based Lure For Mosquito Disease Vectors, Vincent O. Nyasembe, David P. Tchouassi, Charles M. Mbogo, Catherine L. Sole, Christian Pirk, Baldwyn Torto

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Background: Lack of effective vaccines and therapeutics for important arboviral diseases such as Rift Valley fever (RVF) and dengue, necessitates continuous monitoring of vector populations for infections in them. Plant-based lures as surveillance tools has the potential of targeting mosquitoes of both sexes and females of varied physiological states; yet such lures are lacking for vectors of these diseases. Here, we present evidence of the effectiveness of linalool oxide (LO), a single plant-based lure previously developed for malaria vectors in trapping RVF vectors, Aedes mcintoshi and Aedes ochraceus, and dengue vector, Aedes aegypti. Methods: For RVF vectors, we used CDC …

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Effects Of Agroforestry On Pest, Disease And Weed Control: A Meta-Analysis, Lorena Pumariño, Gudeta Weldesemayat Sileshi, Sofia Gripenberg, Riikka Kaartinen, Edmundo Barrios, Mary Nyawira Muchane, Charles Midega, Mattias Jonsson Nov 2015

Effects Of Agroforestry On Pest, Disease And Weed Control: A Meta-Analysis, Lorena Pumariño, Gudeta Weldesemayat Sileshi, Sofia Gripenberg, Riikka Kaartinen, Edmundo Barrios, Mary Nyawira Muchane, Charles Midega, Mattias Jonsson

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Agroforestry practices may influence pest incidence and abundance both through increased top-down regulation by natural enemies and via bottom-up factors such as moderation of microclimate, soil nutrients and water content. We conducted a meta-analysis of the effects of agroforestry on the abundance of invertebrate pests, weeds, natural enemies and plant damage due to pests and diseases. We also tested whether effects of agroforestry were dependent on crop type (annual or perennial), type of pest association (above or belowground) and weed type (parasitic Striga weeds or non-parasitic weeds).Agroforestry practices resulted in lower abundances of both parasitic and non-parasitic weeds, and in …

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High Quality Draft Genomes Of The Mycoplasma Mycoides Subsp. Mycoides Challenge Strains Afadé And B237, Anne Fischer, Ivette Santana-Cruz, Jan Hegerman, Hadrien Gourlé, Elise Schieck, Mathieu Lambert, Suvarna Nadendla, Hezron Wesonga, Rachel A. Miller, Sanjay Vashee, Johann Weber, Jochen Meens, Joachim Frey, Joerg Jores Oct 2015

High Quality Draft Genomes Of The Mycoplasma Mycoides Subsp. Mycoides Challenge Strains Afadé And B237, Anne Fischer, Ivette Santana-Cruz, Jan Hegerman, Hadrien Gourlé, Elise Schieck, Mathieu Lambert, Suvarna Nadendla, Hezron Wesonga, Rachel A. Miller, Sanjay Vashee, Johann Weber, Jochen Meens, Joachim Frey, Joerg Jores

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Members of the Mycoplasma mycoides cluster' represent important livestock pathogens worldwide. Mycoplasma mycoides subsp. mycoides is the etiologic agent of contagious bovine pleuropneumonia (CBPP), which is still endemic in many parts of Africa. We report the genome sequences and annotation of two frequently used challenge strains of Mycoplasma mycoides subsp. mycoides, Afadé and B237. The information provided will enable downstream 'omics' applications such as proteomics, transcriptomics and reverse vaccinology approaches. Despite the absence of Mycoplasma pneumoniae like cyto-adhesion encoding genes, the two strains showed the presence of protrusions. This phenotype is likely encoded by another set of genes.

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The Biosynthesis Of Allelopathic Di-C-Glycosylflavones From The Roots Of Desmodium Incanum (G. Mey.) Dc, Bing Hao, John C. Caulfield, Mary L. Hamilton, John A. Pickett, Charles A.O. Midega, Zeyaur R. Khan, Junru R. Wang, Antony M. Hooper Oct 2015

The Biosynthesis Of Allelopathic Di-C-Glycosylflavones From The Roots Of Desmodium Incanum (G. Mey.) Dc, Bing Hao, John C. Caulfield, Mary L. Hamilton, John A. Pickett, Charles A.O. Midega, Zeyaur R. Khan, Junru R. Wang, Antony M. Hooper

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The allelopathic root exudate of the drought-tolerant subsistence cereal intercrop D. incanum, protecting against the parasitic weed Striga hermonthica, comprises a number of di-C-glycosylflavones specifically containing C-glucosyl, C-galactosyl and C-arabinosyl moieties. Here we demonstrate that the biosynthesis of all compounds containing a C-glucose involves C-glucosylation of 2-hydroxynaringenin with subsequent C-galactosylation, C-glucosylation or C-arabinosylation. In addition, the crude soluble enzyme extract converts two fluorinated 2-hydroxyflavanone analogues to corresponding mono- and di-C-glycosylflavones demonstrating that some differences in C-ring substitution can be tolerated by the plant enzymes. Elucidating the biosynthesis of these C-glycosylflavones (CGFs) has the potential to open up opportunities for transferring …

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Differential Expression Of The Chemosensory Transcriptome In Two Populations Of The Stemborer Sesamia Nonagrioides, Nicolas Glaser, Aurore Gallot, Fabrice Legeai, Myriam Harry, Laure Kaiser, Bruno Le Ru, Paul André Calatayud, Emmanuelle Jacquin-Joly Oct 2015

Differential Expression Of The Chemosensory Transcriptome In Two Populations Of The Stemborer Sesamia Nonagrioides, Nicolas Glaser, Aurore Gallot, Fabrice Legeai, Myriam Harry, Laure Kaiser, Bruno Le Ru, Paul André Calatayud, Emmanuelle Jacquin-Joly

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Among the proposed mechanisms of local adaptation to different ecological environments, transcriptional changes may play an important role. In this study, we investigated whether such variability occurred within the chemosensory organs of a herbivorous insect, for which chemosensation guides most of its host preferences. A European and an African population of the noctuid Sesamia nonagrioides that display significant differences in their ecological preferences were collected on Zea mays and Typha domingensis, respectively. RNAseq were used between the two populations for digital expression profiling of chemosensory organs from larval antennae and palps. Preliminary data on adult female antennae and ovipositors were …

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Evaluating The Sequential Masking Classification Approach For Improving Crop Discrimination In The Sudanian Savanna Of West Africa, Gerald Forkuor, Christopher Conrad, Michael Thiel, Tobias Landmann, Boubacar Barry Oct 2015

Evaluating The Sequential Masking Classification Approach For Improving Crop Discrimination In The Sudanian Savanna Of West Africa, Gerald Forkuor, Christopher Conrad, Michael Thiel, Tobias Landmann, Boubacar Barry

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Classification of remotely sensed data to reveal the spatial distribution of crop types has high potential for improving crop area estimates and supporting decision making. However, remotely sensed crop maps still demand improvements as e.g. variations in farm management practices (e.g. planting and harvesting dates), soil and other environmental factors cause overlaps in features available for classification and thus confusion in error matrices. In this study, a variant of the sequential masking classification technique was applied to multi-temporal optical and microwave remote sensing data (RapidEye, Landsat, TerraSAR-X) to improve the accuracy of crop discrimination in West Africa. This approach employs …

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Farmers' Control Practices Against The Invasive Red Spider Mite, Tetranychus Evansi Baker & Pritchard In Benin, Ginette Y. Azandémè-Hounmalon, Hippolyte D. Affognon, Françoise Assogba Komlan, Manuele Tamò, Komi K.M. Fiaboe, Serge Kreiter, Thibaud Martin Oct 2015

Farmers' Control Practices Against The Invasive Red Spider Mite, Tetranychus Evansi Baker & Pritchard In Benin, Ginette Y. Azandémè-Hounmalon, Hippolyte D. Affognon, Françoise Assogba Komlan, Manuele Tamò, Komi K.M. Fiaboe, Serge Kreiter, Thibaud Martin

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In 2008, the invasive tomato red spider mite Tetranychus evansi (Acari: Tetranychidae), a pest of solanaceous crops, was identified for the first time as the cause of serious damage on tomato (. Solanum lycopersicum L.; Solanaceae) crops in Benin. Since then, frequent outbreaks have been observed on Solanaceae and other leafy vegetables such as purple amaranth (. Amaranthus cruentus L.; Amaranthaceae) and bitter leaf (. Vernonia amygdalina D.; Asteraceae) in all growing areas in southern Benin. The objective of this study was to evaluate the intensity of damage by this invasive pest and the impact of farmers' control practices on …

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Distribution Of Indigenous Strains Of Atoxigenic And Toxigenic Aspergillus Flavus And Aspergillus Parasiticus In Maize And Peanuts Agro-Ecological Zones Of Kenya, Daniel O. Okun, Fathiya M. Khamis, Geoffrey M. Muluvi, Joseph J. Ngeranwa, Fidelis O. Ombura, Moses O. Yongo, Eucharia U. Kenya Sep 2015

Distribution Of Indigenous Strains Of Atoxigenic And Toxigenic Aspergillus Flavus And Aspergillus Parasiticus In Maize And Peanuts Agro-Ecological Zones Of Kenya, Daniel O. Okun, Fathiya M. Khamis, Geoffrey M. Muluvi, Joseph J. Ngeranwa, Fidelis O. Ombura, Moses O. Yongo, Eucharia U. Kenya

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Background: Grains of important food and export crops in Africa are susceptible to contamination by toxin-producing moulds. Aflatoxins are mycotoxins associated with liver damage and cancer in humans and animals. These toxic substances are produced by fungi (such as Aspergillus flavus and Aspergillus parasiticus) in food and feed exposed to poor conditions during crop cultivation, storage or processing of harvest. The presence of aflatoxins in especially maize and peanuts in Kenya is of great concern. Recent developments in the application of atoxigenic strains of these fungi as biological control agents against toxigenic strains could be a solution to the problem. …

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The Invasive American Weed Parthenium Hysterophorus Can Negatively Impact Malaria Control In Africa, Vincent O. Nyasembe, Xavier Cheseto, Fatma Kaplan, Woodbridge A. Foster, Peter E.A. Teal, James H. Tumlinson, Christian Borgemeister, Baldwyn Torto Sep 2015

The Invasive American Weed Parthenium Hysterophorus Can Negatively Impact Malaria Control In Africa, Vincent O. Nyasembe, Xavier Cheseto, Fatma Kaplan, Woodbridge A. Foster, Peter E.A. Teal, James H. Tumlinson, Christian Borgemeister, Baldwyn Torto

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The direct negative effects of invasive plant species on agriculture and biodiversity are well known, but their indirect effects on human health, and particularly their interactions with disease-transmitting vectors, remains poorly explored. This study sought to investigate the impact of the invasive Neotropical weed Parthenium hysterophorus and its toxins on the survival and energy reserves of the malaria vector Anopheles gambiae. In this study, we compared the fitness of An. gambiae fed on three differentially attractive mosquito host plants and their major toxins; the highly aggressive invasive Neotropical weed Parthenium hysterophorus (Asteraceae) in East Africa and two other adapted weeds, …

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Sternal Gland Structures In Males Of Bean Flower Thrips, Megalurothrips Sjostedti, And Poinsettia Thrips, Echinothrips Americanus, In Comparison With Those Of Western Flower Thrips, Frankliniella Occidentalis (Thysanoptera: Thripidae), Stephanie Krueger, Sevgan Subramanian, Saliou Niassy, Gerald B. Moritz Sep 2015

Sternal Gland Structures In Males Of Bean Flower Thrips, Megalurothrips Sjostedti, And Poinsettia Thrips, Echinothrips Americanus, In Comparison With Those Of Western Flower Thrips, Frankliniella Occidentalis (Thysanoptera: Thripidae), Stephanie Krueger, Sevgan Subramanian, Saliou Niassy, Gerald B. Moritz

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Sternal pores are important features for identification of male thrips, especially within the subfamily Thripinae. They vary in shape, size and distribution even between species of one genus. Their functional role is speculated to be that of sex- and/or aggregation pheromone production. Yet, sexual aggregations are not reported in Echinothrips americanus, known to have sternal pores, while we observed aggregations in Megalurothrips sjostedti, previously reported to lack them. We examined the sternal glands and pores of the thripine species E. americanus and M. sjostedti males, in comparison with those of Frankliniella occidentalis using light microscopy, as well as scanning and …

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Influence Of Dietary Experience On The Induction Of Preference Of Adult Moths And Larvae For A New Olfactory Cue, Christophe Petit, Bruno Le Ru, Stéphane Dupas, Brigitte Frérot, Peter Ahuya, Laure Kaiser-Arnauld, Myriam Harry, Paul André Calatayud Aug 2015

Influence Of Dietary Experience On The Induction Of Preference Of Adult Moths And Larvae For A New Olfactory Cue, Christophe Petit, Bruno Le Ru, Stéphane Dupas, Brigitte Frérot, Peter Ahuya, Laure Kaiser-Arnauld, Myriam Harry, Paul André Calatayud

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In Lepidoptera, host plant selection is first conditioned by oviposition site preference of adult females followed by feeding site preference of larvae. Dietary experience to plant volatile cues can induce larval and adult host plant preference. We investigated how the parent's and self-experience induce host preference in adult females and larvae of three lepidopteran stem borer species with different host plant ranges, namely the polyphagous Sesamia nonagrioides, the oligophagous Busseola fusca and the monophagous Busseola nairobica, and whether this induction can be linked to a neurophysiological phenotypic plasticity. The three species were conditioned to artificial diet enriched with vanillin from …

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Climate-Adapted Companion Cropping Increases Agricultural Productivity In East Africa, Charles A.O. Midega, Toby J.A. Bruce, John A. Pickett, Jimmy O. Pittchar, Alice Murage, Zeyaur R. Khan Aug 2015

Climate-Adapted Companion Cropping Increases Agricultural Productivity In East Africa, Charles A.O. Midega, Toby J.A. Bruce, John A. Pickett, Jimmy O. Pittchar, Alice Murage, Zeyaur R. Khan

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Production of cereals, the main staple and cash crops for millions of farmers in sub-Saharan Africa (SSA) is severely constrained by parasitic striga weed Striga hermonthica, stemborers and poor soil fertility. A companion cropping system known as 'push-pull' overcomes these constraints while providing additional soil fertility and forage grass benefits to smallholder farmers. To ensure the technology's long-term sustainability in view of the current and further potential aridification as a consequence of climate change, drought-tolerant crops, Brachiaria cv mulato (border crop) and greenleaf desmodium (intercrop), have been identified and incorporated into a 'climate-adapted push-pull'. The aims of the current study …

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Evolution Of Spermophagus Seed Beetles (Coleoptera, Bruchinae, Amblycerini) Indicates Both Synchronous And Delayed Colonizations Of Host Plants, Gael J. Kergoat, Bruno P. Le Ru, Seyed E. Sadeghi, Midori Tuda, Chris A.M. Reid, Zoltán György, Gwenaëlle Genson, Cibele S. Ribeiro-Costa, Alex Delobel Aug 2015

Evolution Of Spermophagus Seed Beetles (Coleoptera, Bruchinae, Amblycerini) Indicates Both Synchronous And Delayed Colonizations Of Host Plants, Gael J. Kergoat, Bruno P. Le Ru, Seyed E. Sadeghi, Midori Tuda, Chris A.M. Reid, Zoltán György, Gwenaëlle Genson, Cibele S. Ribeiro-Costa, Alex Delobel

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Seed beetles are a group of specialized chrysomelid beetles, which are mostly associated with plants of the legume family (Fabaceae). In the legume-feeding species, a marked trend of phylogenetic conservatism of host use has been highlighted by several molecular phylogenetics studies. Yet, little is known about the evolutionary patterns of association of species feeding outside the legume family. Here, we investigate the evolution of host use in Spermophagus, a species-rich seed beetle genus that is specialized on two non-legume host-plant groups: morning glories (Convolvulaceae) and mallows (Malvaceae: Malvoideae). Spermophagus species are widespread in the Old World, especially in the Afrotropical, …

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Unraveling Host-Vector-Arbovirus Interactions By Two-Gene High Resolution Melting Mosquito Bloodmeal Analysis In A Kenyan Wildlife-Livestock Interface, David Omondi, Daniel K. Masiga, Yvonne Ukamaka Ajamma, Burtram C. Fielding, Laban Njoroge, Jandouwe Villinger Jul 2015

Unraveling Host-Vector-Arbovirus Interactions By Two-Gene High Resolution Melting Mosquito Bloodmeal Analysis In A Kenyan Wildlife-Livestock Interface, David Omondi, Daniel K. Masiga, Yvonne Ukamaka Ajamma, Burtram C. Fielding, Laban Njoroge, Jandouwe Villinger

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The blood-feeding patterns of mosquitoes are directly linked to the spread of pathogens that they transmit. Efficient identification of arthropod vector bloodmeal hosts can identify the diversity of vertebrate species potentially involved in disease transmission cycles. While molecular bloodmeal analyses rely on sequencing of cytochrome b (cyt b) or cytochrome oxidase 1 gene PCR products, recently developed bloodmeal host identification based on high resolution melting (HRM) analyses of cyt b PCR products is more cost-effective. To resolve the diverse vertebrate hosts that mosquitoes may potentially feed on in sub-Saharan Africa, we utilized HRM profiles of both cyt b and 16S …

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Isolation And Identification Of Desmodium Root Exudates From Drought Tolerant Species Used As Intercrops Against Striga Hermonthica, A. M. Hooper, J. C. Caulfield, B. Hao, J. A. Pickett, C. A.O. Midega, Z. R. Khan Jul 2015

Isolation And Identification Of Desmodium Root Exudates From Drought Tolerant Species Used As Intercrops Against Striga Hermonthica, A. M. Hooper, J. C. Caulfield, B. Hao, J. A. Pickett, C. A.O. Midega, Z. R. Khan

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Abstract Plants from the genus Desmodium, in particular D. uncinatum, are used on sub-Saharan small-holder farms as intercrops to inhibit parasitism of cereal crops by Striga hermonthica and Striga asiatica via an allelopathic mechanism. The search for Desmodium species which are adapted to more arid conditions, and which show resilience to increased drought stress, previously identified D. intortum, D. incanum and D. ramosissimum as potential drought tolerant intercrops. Their potential as intercrops was assessed for resource poor areas of rain-fed cereal production where drought conditions can persist through normal meteorological activity, or where drought may have increasing impact through climate …

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Genome-Wide Analysis Of Signatures Of Selection In Populations Of African Honey Bees (Apis Mellifera) Using New Web-Based Tools, Zachary L. Fuller, Elina L. Niño, Harland M. Patch, Oscar C. Bedoya-Reina, Tracey Baumgarten, Elliud Muli, Fiona Mumoki, Aakrosh Ratan, John Mcgraw, Maryann Frazier, Daniel Masiga, Stephen Schuster, Christina M. Grozinger, Webb Miller Jul 2015

Genome-Wide Analysis Of Signatures Of Selection In Populations Of African Honey Bees (Apis Mellifera) Using New Web-Based Tools, Zachary L. Fuller, Elina L. Niño, Harland M. Patch, Oscar C. Bedoya-Reina, Tracey Baumgarten, Elliud Muli, Fiona Mumoki, Aakrosh Ratan, John Mcgraw, Maryann Frazier, Daniel Masiga, Stephen Schuster, Christina M. Grozinger, Webb Miller

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Background: With the development of inexpensive, high-throughput sequencing technologies, it has become feasible to examine questions related to population genetics and molecular evolution of non-model species in their ecological contexts on a genome-wide scale. Here, we employed a newly developed suite of integrated, web-based programs to examine population dynamics and signatures of selection across the genome using several well-established tests, including F ST, pN/pS, and McDonald-Kreitman. We applied these techniques to study populations of honey bees (Apis mellifera) in East Africa. In Kenya, there are several described A. mellifera subspecies, which are thought to be localized to distinct ecological regions. …

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Grower Adoption Of An Integrated Pest Management Package For Management Of Mango-Infesting Fruit Flies (Diptera: Tephritidae) In Embu, Kenya, J. K. Korir, H. D. Affognon, C. N. Ritho, W. S. Kingori, P. Irungu, S. A. Mohamed, S. Ekesi Jun 2015

Grower Adoption Of An Integrated Pest Management Package For Management Of Mango-Infesting Fruit Flies (Diptera: Tephritidae) In Embu, Kenya, J. K. Korir, H. D. Affognon, C. N. Ritho, W. S. Kingori, P. Irungu, S. A. Mohamed, S. Ekesi

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Mango (Mangifera indica L.) is a well-recognized fruit of economic and nutritional importance to smallholder farmers across Africa. Production and marketing of this fruit is, however, severely hampered by fruit fly infestation that is responsible for enormous fruit losses. In Kenya, control of this pest is primarily dependent on the use of chemical pesticides, a strategy that has been shown to be ineffective. Although the recently introduced fruit fly integrated pest management (IPM) package developed by the International Centre of Insect Physiology and Ecology (icipe) has proved to be effective against this pest, there is little demonstrable investigation on its …

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Adoption Of Modern Beekeeping And Its Impact On Honey Production In The Former Mwingi District Of Kenya: Assessment Using Theory-Based Impact Evaluation Approach, Hippolyte D. Affognon, W. S. Kingori, A. I. Omondi, M. G. Diiro, B. W. Muriithi, S. Makau, S. K. Raina Jun 2015

Adoption Of Modern Beekeeping And Its Impact On Honey Production In The Former Mwingi District Of Kenya: Assessment Using Theory-Based Impact Evaluation Approach, Hippolyte D. Affognon, W. S. Kingori, A. I. Omondi, M. G. Diiro, B. W. Muriithi, S. Makau, S. K. Raina

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This study used the theory-based impact evaluation approach to understand as to how promotion of beekeeping by the Commercial Insects Programme (CIP) of the International Centre of Insect Physiology and Ecology (icipe) has had an impact on honey production in the former Mwingi District of Kenya (now merged into Kitui County). We examined the adoption of modern hives promoted by icipe and applied data envelopment analysis (DEA) to assess the technical efficiency (TE) of participants in CIP. CIP participants had an average TE of 0.56, which was significantly higher than that of non-participants in the former Kitui District (average TE …

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Predicting The Impact Of Temperature Change On The Future Distribution Of Maize Stem Borers And Their Natural Enemies Along East African Mountain Gradients Using Phenology Models, Sizah Mwalusepo, Henri E.Z. Tonnang, Estomih S. Massawe, Gerphas O. Okuku, Nancy Khadioli, Tino Johansson, Paul André Calatayud, Bruno Pierre Le Ru Jun 2015

Predicting The Impact Of Temperature Change On The Future Distribution Of Maize Stem Borers And Their Natural Enemies Along East African Mountain Gradients Using Phenology Models, Sizah Mwalusepo, Henri E.Z. Tonnang, Estomih S. Massawe, Gerphas O. Okuku, Nancy Khadioli, Tino Johansson, Paul André Calatayud, Bruno Pierre Le Ru

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Lepidopteran stem borers are among the most important pests of maize in East Africa. The objective of the present study was to predict the impact of temperature change on the distribution and abundance of the crambid Chilo partellus, the noctuid Busseola fusca, and their larval parasitoids Cotesia flavipes and Cotesia sesamiae at local scale along Kilimanjaro and Taita Hills gradients in Tanzania and Kenya, respectively. Temperature-dependent phenology models of pests and parasitoids were used in a geographic information system for mapping. The three risk indices namely establishment, generation, and activity indices were computed using current temperature data record from local …

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Mosquito Attraction: Crucial Role Of Carbon Dioxide In Formulation Of A Five-Component Blend Of Human-Derived Volatiles, Joop J.A. Van Loon, Renate C. Smallegange, Gabriella Bukovinszkiné-Kiss, Frans Jacobs, Marjolein De Rijk, Wolfgang R. Mukabana, Niels O. Verhulst, David J. Menger, Willem Takken Jun 2015

Mosquito Attraction: Crucial Role Of Carbon Dioxide In Formulation Of A Five-Component Blend Of Human-Derived Volatiles, Joop J.A. Van Loon, Renate C. Smallegange, Gabriella Bukovinszkiné-Kiss, Frans Jacobs, Marjolein De Rijk, Wolfgang R. Mukabana, Niels O. Verhulst, David J. Menger, Willem Takken

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Behavioral responses of the malaria mosquito Anopheles coluzzii (An. gambiae sensu stricto molecular ‘M form’) to an expanded blend of human-derived volatiles were assessed in a dual-port olfactometer. A previously documented attractive three-component blend consisting of NH3, (S)-lactic acid, and tetradecanoic acid served as the basis for expansion. Adding 4.5 % CO2 to the basic blend significantly enhanced its attractiveness. Expansion of the blend with four human-derived C4-volatiles was then assessed, both with and without CO2. Only when CO2 was offered simultaneously, did addition of a specific concentration of 3-methyl-1-butanol or 3-methyl-butanoic acid significantly enhance attraction. The functional group at …

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Electrophysiological And Behavioral Characterization Of Bioactive Compounds Of The Thymus Vulgaris, Cymbopogon Winterianus, Cuminum Cyminum And Cinnamomum Zeylanicum Essential Oils Against Anopheles Gambiae And Prospects For Their Use As Bednet Treatments, Emilie Deletre, Fabrice Chandre, Livy Williams, Claire Duménil, Chantal Menut, Thibaud Martin Jun 2015

Electrophysiological And Behavioral Characterization Of Bioactive Compounds Of The Thymus Vulgaris, Cymbopogon Winterianus, Cuminum Cyminum And Cinnamomum Zeylanicum Essential Oils Against Anopheles Gambiae And Prospects For Their Use As Bednet Treatments, Emilie Deletre, Fabrice Chandre, Livy Williams, Claire Duménil, Chantal Menut, Thibaud Martin

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Background: Laboratory and field studies showed that repellent, irritant and toxic actions of common public health insecticides reduce human-vector contact and thereby interrupt disease transmission. One of the more effective strategies to reduce disease risk involves the use of long-lasting treated bednets. However, development of insecticide resistance in mosquito populations makes it imperative to find alternatives to these insecticides. Our previous study identified four essential oils as alternatives to pyrethroids: Thymus vulgaris, Cymbopogon winterianus, Cuminum cyminum, Cinnamomum zeylanicum. The objectives of this study were to identify active compounds of these essential oils, to characterize their biological activity, and to examine …

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New Directions For Improving Crop Resistance To Insects By Breeding For Egg Induced Defence, Amanuel Tamiru, Zeyaur R. Khan, Toby J.A. Bruce Jun 2015

New Directions For Improving Crop Resistance To Insects By Breeding For Egg Induced Defence, Amanuel Tamiru, Zeyaur R. Khan, Toby J.A. Bruce

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Plant defence responses to insect oviposition, including tritrophic interactions with natural enemies of herbivores, have rarely been targeted in crop breeding programmes. Emission of herbivore induced plant volatiles (HIPVs) that attract natural enemies early on at the egg-laying stage of herbivore attack could provide timely biological control of pests and deter subsequent oviposition. This is needed in an agroecological context where the third trophic level often does not keep pace with the growth rate of pests. Our very recent data, using maize as an example, show that herbivore egg induced volatile emission is very rare in commercial hybrids but common …

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Analysing Chemical Attraction Of Gravid Anopheles Gambiae Sensu Stricto With Modified Bg-Sentinel Traps, Michael N. Okal, Manuela Herrera-Varela, Paul Ouma, Baldwyn Torto, Steven W. Lindsay, Jenny M. Lindh, Ulrike Fillinger Jun 2015

Analysing Chemical Attraction Of Gravid Anopheles Gambiae Sensu Stricto With Modified Bg-Sentinel Traps, Michael N. Okal, Manuela Herrera-Varela, Paul Ouma, Baldwyn Torto, Steven W. Lindsay, Jenny M. Lindh, Ulrike Fillinger

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Background: Cues that guide gravid Anopheles gambiae sensu lato to oviposition sites can be manipulated to create new strategies for monitoring and controlling malaria vectors. However, progress towards identifying such cues is slow in part due to the lack of appropriate tools for investigating long-range attraction to putative oviposition substrates. This study aimed to develop a relatively easy-to-use bioassay system that can effectively analyse chemical attraction of gravid Anopheles gambiae sensu stricto. Methods: BG-Sentinel™ mosquito traps that use fans to dispense odourants were modified to contain aqueous substrates. Choice tests with two identical traps set in an 80 m2 screened …

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Regulating Edible Insects: The Challenge Of Addressing Food Security, Nature Conservation, And The Erosion Of Traditional Food Culture, A. Halloran, P. Vantomme, Y. Hanboonsong, S. Ekesi Jun 2015

Regulating Edible Insects: The Challenge Of Addressing Food Security, Nature Conservation, And The Erosion Of Traditional Food Culture, A. Halloran, P. Vantomme, Y. Hanboonsong, S. Ekesi

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Entomophagy is a common practice in many regions of the world but there are few examples of national regulations that govern insects for human consumption. Where entomophagy is not common, the current regulatory discourse focuses primarily on food safety and consumer protection. In countries where insects contribute to local diets, nature conservation is often an issue of high importance. This paper investigates the variation in the ways in which entomophagy and its related activities are currently regulated in Thailand, Switzerland, Kenya and Canada. Authoritative bodies who are responsible and the roles they play are discussed. Insects have only recently entered …

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