References of "Nguyen, Bach Kim"
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See detailParasitisme d’Apis mellifera adansonii (Latreille 1804) et de Meliponula bocandei (Spinola 1853) par Aethina tumida (Murray 1867): premier recensement au Gabon et impact sur la domestication
Fabre Anguilet, Edgard ULg; Alabi, Taofic ULg; Haubruge, Eric ULg et al

in Entomologie Faunistique = Faunistic Entomology (2017), 70

The small hive beetle, Aethina tumida (Murray 1867), has been reported in many countries in sub-Saharan Africa. This parasite is considered as a minor threat to strong Apis mellifera (Linnaeus 1758 ... [more ▼]

The small hive beetle, Aethina tumida (Murray 1867), has been reported in many countries in sub-Saharan Africa. This parasite is considered as a minor threat to strong Apis mellifera (Linnaeus 1758) colonies in Africa and as a major threat during the transfer of wild colonies of Meliponula bocandei (Spinola 1853) in hives. There is no data for Gabon and the state of wild colonies is still poorly known. Then, this study aims (1) to make a first prevalence assessment of A. tumida in wild colonies of A. mellifera and M. bocandei in Gabon; (2) to verify the effectiveness of quarantine implementation during the transfer of M. bocandei in hives against A. tumida. For that, 59 nests of A. mellifera and 25 nests of M. bocandei were inspected in two locations. Twelve nests of M. bocandei were transferred in hives with a quarantine for 4 days while 12 nests were transferred without quarantine. Aethina tumida was observed in more than 70 % of A. mellifera nests and in a single nest of M. bocandei. No damage was observed in nests of A. mellifera. More than 60 % of brood sections in quarantine or not were destroyed by A. tumida in hives. This study provided first evidence of the presence of A. tumida in Gabon and the need to develop a more effective method to domesticate M. bocandei in hives. [less ▲]

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See detailExtraction of honey polyphenols: Method development and evidence of cis isomerization
Istasse, Thibaut ULg; Jacquet, Nicolas ULg; Berchem, Thomas ULg et al

in Analytical Chemistry Insights (2016), 11

Honey polyphenols have been studied with the objective of relating honeys to their floral sources. Initially synthesized by plant, these polyphenols can be found in the plant’s nectar, where they are ... [more ▼]

Honey polyphenols have been studied with the objective of relating honeys to their floral sources. Initially synthesized by plant, these polyphenols can be found in the plant’s nectar, where they are collected by bees which convert the nectar into honey. Consequently, polyphenols constitute minor honey components. The development of a solid phase extraction method for honey polyphenols is presented herein. The technique employs Amberlite XAD-2 adsorbent and was tested on monofloral honeys from six different plants: acacia, chestnut, eucalyptus, thyme, sunflower and wild carrot. Analyses were performed using high performance liquid chromatography coupled with UV detection and mass spectrometry. Several phenolic acids and flavonoids were identified: caffeic and p-coumaric acids, quercetin, kaempferol, naringenin, chrysin and pinocembrin. Generally, the quantity of a given polyphenol in the honey was around 0.2 mg/100g of honey, except for chestnut honey which contained around 3.0 mg of p-coumaric acid/100g of honey. Analyses highlighted significant formation of cis isomers for phenolic acids during the extraction despite protection from light. [less ▲]

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See detailCaractérisation et étude du potentiel de valorisation des composés phénoliques de miels monofloraux
Istasse, Thibaut ULg; Nguyen, Bach Kim ULg; Richel, Aurore ULg

Conference (2016, January 20)

Présentation des recherches effectuées dans le cadre du travail de fin d'étude sur les composés phénoliques présents dans les miels monofloraux. Ces composés ont été extraits par extraction en phase ... [more ▼]

Présentation des recherches effectuées dans le cadre du travail de fin d'étude sur les composés phénoliques présents dans les miels monofloraux. Ces composés ont été extraits par extraction en phase solide et analysés par chromatographie liquide avec détection UV et spectrométrie de masse. [less ▲]

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See detailFirst survey on prevalence and infestation rates of Varrroa mite in Gabon
Fabre Anguilet, Edgard ULg; Alabi, Taofic ULg; Bengone Ndong, Toussaint et al

in Communications in Agricultural and Applied Biological Sciences (2016), 81(3), 299-305

Varroa mites cause considerable damage to Apis mellifera Linnaeus colonies in North America, Europe and Asia. To control this parasite, beekeepers in these parts of world have to use chemical acaricides ... [more ▼]

Varroa mites cause considerable damage to Apis mellifera Linnaeus colonies in North America, Europe and Asia. To control this parasite, beekeepers in these parts of world have to use chemical acaricides. In Africa, this pest has been identified, and survey of Varroa infestation rates showed a lot of variation across honey bee sub-species. Generally, African colonies seemed to be resistant or tolerant to the presence of Varroa mite. The objective of our study is to explore the presence, prevalence and infestation rates of Varroa mite in Gabon. The presence and quantitative assessment of Varroa mites were performed in 55 wild colonies of Apis mellifera adansonii Latreille in two locations. Our results showed that: (1) 70% and 48% of the wild colonies studied were infested with Varroa destructor according to locations, (2) Varroa infestation rate was lower than 0.5 mite per 100 bees regardless location. The infestation rates obtained were still very low compared to those observed in various other regions in Africa. In perspective, it would be interesting to explore the reasons that could explain the low infestation rates which were observed. [less ▲]

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See detailResidues in beeswax: a health risk for the consumer of honey and beeswax ?
Wilmart, O; Legrève, A; Scippo, Marie-Louise ULg et al

in Journal of Agricultural and Food Chemistry (2016), 64(44), 84258434

A scenario analysis in regard to the risk of chronic exposure of consumers to residues through the consumption of contaminated honey and beeswax was conducted. Twenty-two plant protection products and ... [more ▼]

A scenario analysis in regard to the risk of chronic exposure of consumers to residues through the consumption of contaminated honey and beeswax was conducted. Twenty-two plant protection products and veterinary substances of which residues have already been detected in beeswax in Europe were selected. The potential chronic exposure was assessed by applying a worst-case scenario based on the addition of a “maximum” daily intake through the consumption of honey and beeswax to the theoretical maximum daily intake through other foodstuffs. For each residue, the total exposure was finally compared to the acceptable daily intake. It is concluded that the food consumption of honey and beeswax contaminated with these residues considered separately does not compromise the consumer’s health, provided proposed action limits are met. In regard to residues of flumethrin in honey and in beeswax, “zero tolerance” should be applied. [less ▲]

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See detailAssessment of the species richness of highly eusocial bees according with habitat in Gabon
Fabre Anguilet, Edgard ULg; Bengone Ndong, Toussaint; Nguyen, Bach Kim ULg et al

Poster (2015, May 18)

Bees are among the most e ective pollinators. These insects include honeybee and stin- gless bee. In Africa, habitat loss is the main threat to these insects. This loss of habitat is largely due to ... [more ▼]

Bees are among the most e ective pollinators. These insects include honeybee and stin- gless bee. In Africa, habitat loss is the main threat to these insects. This loss of habitat is largely due to various human activities. An evaluation of the richness of social bees in three locaties in Gabon (Central Africa) was conducted from October 2013 to March 2014: Kougouleu who underwent deforestation and implantation of food crops, forest area Mas- sengalini in bu er zone of protected area of Lope and Lekokodiba in logging concession of Preccious Woods Gabon. For this, a collection was conducted using yellow traps lled with a mixture of water and honey and using a hand vacuum in 20 sites in each area. The number of species was compared to that estimated there are about thirty years. Eleven species of social bees (Apis mellifera adansonii and ten stingless bee species) were collected, of which 5 to Kougouleu, 8 to Massengalini and 11 to L ekokodiba. Honeybee has been collected in all localities. Forest localities are distinguished from Kougouleu by higher species diversity. This di erence is highly signi cant (Kruskal-Wallis 2 = 45.362, df = 2 and p-value<0.001). A decrease of approximately 50% of the number of stingless bee species in 30 years was found to Kougouleu, while the number of social bee species varies little in forest localities. Our study shows that the loss of forest habitat causes a decline in the species richness of social bees and stingless bees are more sensitive to this loss as the honeybee. [less ▲]

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See detailMeliponini and Apini in Africa (Apidae: Apinae): a review on the challenges and stakes bound to their diversity and their distribution
Fabre Anguilet, Edgard ULg; Nguyen, Bach Kim ULg; Bengone Ndong, Toussaint et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2015), 19(4),

Introduction. Meliponini and Apini contribute to the pollination of flowering plants and to improving agricultural yields. These bees’ diversity, distribution and abundance depend on the ecosystem in ... [more ▼]

Introduction. Meliponini and Apini contribute to the pollination of flowering plants and to improving agricultural yields. These bees’ diversity, distribution and abundance depend on the ecosystem in which they evolve. The present work aims to summarize the diversity, distribution, abundance, potential threats, challenges and issues faced with respect to these social bees in Africa. Literature. In Africa, there were 21 species of Meliponini and 2 species of Apini (Apis). Aspects related to the species diversity, distribution, biology, ecology and abundance of nests are poorly documented, especially for Meliponini. This deficit could be related to a lack of interest of the authors or the various difficulties in performing these studies in Africa. With regard to the difficulties, there is a need to clarify the taxonomy of Meliponini, and the observation of nests in certain forest environments is difficult. Nest predation and habitat loss are the main threats that could cause the depopulation of certain social bee species in Africa. If there is currently new evidence that diseases and pests did not endanger these bees, then there is a need for further studies for better assessment of the risks that are associated with these potential threats. Conclusions. Work on the diversity, distribution and abundance of the social bees must be strengthened to address the challenges that are related to these insects in Africa. Indeed, this approach will contribute to answering the challenges of sustainable management of the biodiversity and economic and agricultural issues. [less ▲]

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See detailEvaluation of two capture methods in the assessment of species richness of eusocial bees in Gabon
Fabre Anguilet, Edgard ULg; Bengone Ndong, Toussaint; Francis, Frédéric ULg et al

Poster (2014, December 13)

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See detailHoney bee colony strength - Assessing accuracy of the Liebefeld estimation method
Leclercq, Gil ULg; Gengler, Nicolas ULg; Francis, Frédéric ULg et al

Poster (2014, December 12)

Honey bee colony strength (number of adult bees in a colony) is a crucial character used for both breeding and research. In breeding programs a rough estimate is usually sufficient to select strong ... [more ▼]

Honey bee colony strength (number of adult bees in a colony) is a crucial character used for both breeding and research. In breeding programs a rough estimate is usually sufficient to select strong colonies. On the other hand, the accuracy of this character can deeply affect the quality of several studies in both fundamental and applied research. For example these studies are related to the assessment of low demographic variations following a stress, or the estimate of a host-parasite ratio (e.g. involving the mite Varroa destructor Anderson & Trueman). The “Liebefeld estimation method” is extensively used in these studies while its accuracy remains weakly documented. Our goal is to provide more information on the accuracy of this method. [less ▲]

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See detailPhysico-chemical properties and aroma profile of Acacia Honey produced in Romania
Madas, Mariana-Niculina ULg; Francis, Frédéric ULg; Marghitas, L.A. et al

in Communications in Agricultural and Applied Biological Sciences (2014, February 07), 79(1), 133-135

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See detailLa mortalité de l'abeille domestique : entre communication médiatique et scientifique
Leclercq, Gil ULg; Francis, Frédéric ULg; Haubruge, Eric ULg et al

Conference given outside the academic context (2013)

A l’heure actuelle, plus personne n’ignore que nos populations d’abeilles domestiques subissent de lourdes pertes, chez nous comme dans de nombreux autres pays. Les médias ont axés leur communication sur ... [more ▼]

A l’heure actuelle, plus personne n’ignore que nos populations d’abeilles domestiques subissent de lourdes pertes, chez nous comme dans de nombreux autres pays. Les médias ont axés leur communication sur des messages très simples. On en retient surtout que les pesticides tuent nos abeilles. La conclusion au problème est dès lors évidente : il faut interdire les pesticides. Mais cette problématique est-elle si simple ? Ce message est-il le même que celui communiqué par les scientifiques ? Cette conférence permettra de faire le point sur les pertes en colonies d’abeilles domestiques. On s’intéressera plus particulièrement aux pertes de ces dernières années en Belgique, cartes et chiffres à l’appui. On y verra aussi comment chacun, qu’il soit citoyen, apiculteur, agriculteur,… peut aider à enrayer cette mortalité effrayante. [less ▲]

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See detailStandard epidemiological methods to understand and improve Apis mellifera health
vanEngelsdorp, D; Lengerich, E; Spleen, A et al

in Journal of Apicultural Research (2013), 52(1),

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See detailHydroxymethylfurfural: a possible emergent cause of honey bee mortality?
Zirbes, Lara ULg; Nguyen, Bach Kim ULg; de Graaf, DC et al

in Journal of Agricultural and Food Chemistry (2013), 61(49), 11865-11870

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See detailDiversité de l’abeille & sélection de souches tolérantes à Varroa destructor
Leclercq, Gil ULg; Francis, Frédéric ULg; Haubruge, Eric ULg et al

Conference given outside the academic context (2012)

Présentation des 2 volets de recherche du projet "Selapis" (D31-1280) : la diversité de l'abeille et la sélection de souches tolérantes au Varroa

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See detailEvaluation of the genetic diversity of honey bees, Apis mellifera L. in the Walloon Region and selection of strains tolerant to the mite Varroa destructor Anderson and Trueman
Leclercq, Gil ULg; Nguyen, Bach Kim ULg; Gengler, Nicolas ULg et al

Poster (2012, February 10)

For more than a decade, high losses of honey bee colonies have been noticed in several countries, including Belgium. Currently often the mite Varroa destructor is considered a main threat for beekeeping ... [more ▼]

For more than a decade, high losses of honey bee colonies have been noticed in several countries, including Belgium. Currently often the mite Varroa destructor is considered a main threat for beekeeping. In view of the inefficiency of the current chemical treatments, one of the solutions is to select honey bees tolerant to this parasite using genomic selection. To reach this objective the genetic diversity of honey bees needs first to be studied using mainly ‘Single Nucleotide Polymorphisms’ (SNP). Records and samples will be collected all over the Walloon Region in order to create an informative phenotypic and genomic data base that will be used for ‘Genome Wide Association Studies’ (GWAS) to detect associations between SNPs and tolerance, and to select bees tolerant to Varroa destructor. [less ▲]

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See detailCalculating and Reporting Managed Honey Bee Colony Losses
vanEngelsdorp, Dennis; Brodschneider, Robert; Brostaux, Yves ULg et al

in Yoder, Jay (Ed.) Honey Bee Colony Health (2011)

Detailed reference viewed: 97 (5 ULg)