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American Journal of Analytical chemistry 2012年第1期3卷 67-75页

作者： christophe Y.Fischer Pascal Laurent Stephanie Heuskin Delphine Durieux Eric Haubruge Francois J.Verheggen georges c.lognay Department of Analytical chemistry Gembloux Agro-Bio TechLiege UniversityLiegeBelgium Department of General and Organic chemistry Gembloux Agro-Bio TechLiege UniversityLiegeBelgium Department of Biological and Industrial chemistry Gembloux Agro-Bio TechLiege UniversityLiegeBelgium Department of Functional and Evolutionary Entomology Gembloux Agro-Bio TechLiege UniversityLiegeBelgium

These last few years the multicolored Asian ladybird, Harmonia axyridis (Pallas), previously introduced in Europe and North America as a biological control agent, has swiftly spread out on those territories and turns out to be a pest in several ways. In order to improve understanding of several key points of the biology of this ladybird, a novel fast-Gc method of quantification of harmonine, the main defense alkaloid of H. axyridis, has been designed and validated using the accuracy profile concept for concentrations ranging from 13 to 264 μg/individual. This method allows quantifying harmonine in a single insect with a maximal error risk of 20%. For ladybirds collected in spring, mean harmonine concentration observed was 106.6 μg/individual with a very high standard deviation of 80.2 μg/individual, which can easily be explained by the strong asymmetry of the results distribution. Males and females seem equally chemically protected as the harmonine concentration did not significantly differ between sexes. This method is currently used to improve our comprehension of several key points of H. axyridis biology including aggregation behavior and aposematism.

关键词： Alkaloid Harmonine Harmonia axyridis Fast-Gc Validation

Do aphids actively search for ant partners？

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Insect Science 2015年第2期22卷 283-288页

作者： christophe Y. Fischer Maryse Vanderplanck georges c. lognay claire Detrain Francois J. Verheggen Laboratory of Analytical chemistry University of Liege Gembloux Agro-Bio Tech Gembloux Research Institute of Biosciences Laboratory of Zoology University of Mons Mons Unit of Social Ecology Universit6 Libre de Bruxelles Brussels Department of Functional and Evolutionary Entomology University of Liege Gembloux Agro-Bio Tech Gembloux Belgium

The aphid-ant mutnalistic relationships are not necessarily obligate for neither partners but evidence is that such interactions provide them strong advantages in terms of global fitness. While it is largely assumed that ants actively search for their mutualistic partners namely using volatile cues; whether winged aphids （i.e., aphids＇ most mobile form） are able to select ant-frequented areas had not been investigated so far. Ant-frequented sites would indeed offer several advantages for these aphids including a lower predation pressure through ant presence and enhanced chances of establishing mutuaslistic interactions with neighbor ant colonies. In the field, aphid colonies are often observed in higher densities around ant nests, which is probably linked to a better survival ensured by ants＇ services. Nevertheless, this could also result from a preferential establishment of winged aphids in ant-frequented areas. We tested this last hypothesis through different ethological assays and show that the facultative myrmecophilous black bean aphid, Aphisfabae L., does not orientate its search for a host plant preferentially toward ant-frequented plants. However, our results suggest that ants reduce the number of winged aphids leaving the newly colonized plant. Thus, ants involved in facultative myrmecophilous interactions with aphids appear to contribute to structure aphid populations in the field by ensuring a better establishment and survival of newly established colonies rather than by inducing a deliberate plant selection by aphid partners based on the proximity of ant colonies.

关键词： ant aphid Aphisfabae Lasius niger mutualism partner research

Bacteria may contribute to distant species recognition in ant-aphid mutualistic relationships

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Insect Science 2017年第2期24卷 278-284页

作者： christophe Y. Fischer claire Detrain Philippe Thonart Eric Haubruge Frederic Francis Francois J. Verheggen georges c. lognay Laboratory of Analytical chemistry University of Liege Gembloux Agro-Bio Tech Passage des Deportes 2 5030 Gembloux Unit of Social Ecology Universite Libre de Bruxelles CP231 50 avenue F. Roosevelt B-1050 Brussels Walloon center of Industrial Biology University of Liege B40 Sart-Tilman 4000 Liege 4Functional and Evolutionary Entomology University of Liege Gembloux Agro-Bio Tech Passage des Deportes 2 5030 Gembloux Belgium

Mutualistic interactions between ant and aphid species have been the subject of considerable historical and contemporary investigations, the primary benefits being clean- ing and protection for the aphids and carbohydrate-rich honeydew for the ants. Questions remained, however, as to the volatile semiochemical factor influencing this relationship. A recent study highlighted the role of bacterial honeydew volatile compounds in ant at- traction. Here, ant＇s ability to distantly discriminate 2 aphid species was investigated based on bacterial honeydew semiochemicals emissions using a two-way olfactometer. Both the mutualistic aphid Aphis fabae L. and the nonmyrmecophilous aphid Acyrthosiphon pisum Harris were found to be attractive for the ant Lasius niger L. The level of attraction was similar in both assays （control vs. one of the aphid species）. However, when given a choice between these 2 aphid species, ants showed a significant preference for Aphis fabae. Honeydew volatiles, mostly from bacterial origins, are known to be a key element in ant attraction. Using the same olfactometry protocol, the relative attractiveness of volatiles emitted by honeydews collected from each aphid species and by bacteria isolated from each honeydew was investigated. Again, ants significantly preferred volatiles released by Aphis fabae honeydew and bacteria. This information suggests that microbial honeydew volatiles enable ants to distantly discriminate aphid species. These results strengthen the interest of studying the occurrence and potential impact of microorganisms in insect symbioses.

关键词： ant aphid bacteria honeydew mutualism recognition VOc

Is non-host pollen suitable for generalist bumblebees？

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Insect Science 2018年第2期25卷 259-272页

作者： Maryse Vanderplanck Sylvain Decleves Nathalie Roger corentin Decroo Guillaume caulier Gaetan Glauser Pascal Gerbaux georges lognay Aurore Richel Nathalie Escaravage Denis Michez Laboratory of Zoology Research Institute for Biosciences University of Mons--UMONS Mons Organic Synthesis and Mass Spectrom- etry Laboratory Interdisciplinary Center for Mass Spectrometry University of Mons--UMONS Mons Research Institute for Biosciences Biology of Marine Organisms and Biomimetics University of Mons--UMONS Mons Belgium Neuch＆tel Platform of Analytical chem- istry University of Neuch＆tel Neuchtel Switzerland Laboratory of Analytical chemistry University of Liege Gembloux Agro-Bio Tech Gembloux Unit of Biological and Industrial chemistry （cBI） University of Liege Gembloux Agro-Bio Tech Gembloux Belgium Laboratoire Evolution et Diversity Biologique （EDB） CNRS ENFA UMR 5174 University Toulouse 3 Paul Sabatier Toulouse France

current evidence suggests that pollen is both chemically and structurally protected. Despite increasing interest in studying bee-flower networks, the constraints for bee development related to pollen nutritional content, toxicity and digestibility as well as their role in the shaping of bee-flower interactions have been poorly studied. In this study we combined bioassays of the generalist bee Bombus terrestris on pollen of cirsium, Trifolium, Salix, and cistus genera with an assessment of nutritional content, toxicity, and digestibility of pollen. Microcolonies showed significant differences in their development, non-host pollen of cirsium being the most unfavorable. This pollen was characterized by the presence of quite rare 37-sterols and a low digestibility. cirsium consumption seemed increase syrup collection, which is probably related to a detoxification mixing behavior. These results strongly suggest that pollen traits may act as drivers of plant selection by bees and partly explain why Asteraceae pollen is rare in bee generalist diet.

关键词： bee-flower interactions generalist bees pollen defences

Testing semiochemicals from aphid, plant and conspecific： attraction of Harmonia axyridis

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Insect Science 2012年第3期19卷 372-382页

作者： Pascal D. Leroy Thomas Schillings Julien Farmakidis Stephanie Heuskin georges lognay Francois J. Verheggen Yves Brostaux Eric Haubruge Frederic Francis Departments of Functional and Evolutionary Entomology Departments of Analytical chemistry Departments of Applied Statistics Computer Science and Mathematics University of Liege Gembloux Agro-Bio Tech Gembloux Belgium

Harmonia axyridis Pallas （coleoptera： coccinellidae） is an invasive specie affecting the dynamics and composition of several guilds. Nowadays, no biological control method is available to reduce the populations of this harmful coccinellid. Attractants and semiochemicals seem to be the best alternative but only few studies have tested the impact of semiochemicals on this Asian lady beetle. In this work, through wind- tunnel experiments, semiochemicals from aphids （Z,E-nepetalactone, [E]-β-farnesene, a-pinene and β-pinene）, from coccinellids （[-]-β-earyophyllene） and from the nettle Urtica dioica L. were evaluated as potential attractants. The nettle volatile compounds （[Z]-3- hexenol and [E]-2-hexenal） were extracted using a clevenger Apparatus and identified by headspace gas chromatography-mass spectroscopy. In the wind-tunnel experiments, the main components of the aphid alarm pheromone as well as a component of the aphid sexual pheromone strongly attracted both sexes of the Asian lady beetle while （-）-β- caryophyllene only attracted few individuals and had no impact on the males. The nettle extract as well as the （Z）-3-hexenol oriented both males and females to the odor source. The （E）-2-hexenal was shown to have no effect on females even if this green leaf volatile attracted males. Because Z,E-nepetalactone was identified as the most efficient attractant in the wind-tunnel experiments, this volatile was also tested in a potato field where H. axyridis has been showed to respond to this semiochemical. This study highlighted that Z,E-nepetalactone orientated the Asian lady beetle H. axyridis under natural condi- tions, indicating that this volatile compound could certainly help for an efficient biological control approach against this invasive specie.

关键词： aphids attractant Harmonia axyridis plant semiochemicals wind-tunnel

Honeydew volatile emission acts as a kairomonal message for the Asian lady beetle Harmonia axyridis （coleoptera： coccinellidae）

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Insect Science 2012年第4期19卷 498-506页

作者： Pascal D. Leroy Stephanie Heuskin Ahmed Sabri Fran( ois J. Verheggen Julien Farmakidis georges lognay Philippe Thonart Jean-Paul Wathelet Yves Brostaux Eric Haubruge Departments of Functional and Evolutionary Entomology Departments of Analytical chemistry University of Liege Gembloux Agro-BioTech Walloon center of Industrial Biology University of Liege B40 4000 Sart-Tilman Departments of General and Organic chemistry Departments of Appfied Statistics Computer Science and Mathematics University of Liege Gembloux Agro-Bio Tech Gembloux Belgium

The Asian lady beetle Harmonia axyridis Pallas is considered as an invasive species in most territories where it has been introduced. Because aphid honeydew acts as an attraetant for many aphid predators and parasitoids, the objectives of this work were to collect and identify the volatile compounds released from the aphid excretory product to evaluate how these semiochemicals could affect the H. axyridis foraging behavior. Twelve volatile chemicals were identified from the Megoura viciae Buckton honeydew including four alcohols, three ketones, three aldehydes, a pyrazine and a monoterpene. The volatiles 3-methyl-l-butanol and 3-methyl-butanal were highlighted as the two most abundant semiochemicals released from the M. viciae honeydew. Vieia faba L. plants treated with crude honeydew attracted more than 80% of the tested individuals with 40% of attracted beetles located on the plant. Four volatile compounds （3-hydroxy-2-butanone, 3-methyl-butanal, 3-methyl-1-butanol and limonene） were also highlighted to attract more than 75% of the coccinellids toward the odor source and to locate about 35% of them on the plants. Limonene was the most efficient attractant since 89% of the H. axyridis responded to this odor. The use of the identified semiochemicals as well as the composition of an artificial honeydew could certainly be helpful to control the dispersal of the Asian lady beetle H. axyridis.

关键词： aphid honeydew attractant Harmonia axyridis kairomone semiochemicals

Larvicidal activity of Neem oil and three plant essential oils from Senegal against chrysodeixis chalcites(Esper, 1789)

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Asian Pacific Journal of Tropical Biomedicine 2018年第1期8卷 67-72页

作者： Saliou Ngom Raimundo cabrera Perez Ma Anta Mbow Rokhaya Fall Saliou Niassy Andreea cosoveanu Serigne Mbacké Diop El Hadji Barka Ndiaye Moussoukhoye Diop georges lognay Institut Sénégalais de Recherches Agricoles Unidad de Fitopatologia Facultad de Biología Universidad de la Laguna Département de chimie Faculté des Sciences et Techniques Université Cheikh Anta Diop de Dakar Development University of Pretoria Gembloux Agro-Bio Tech Université de Liège Chimie Analytique Department Agro Bio Tech

Objective: To evaluate the insecticide, larvicidal and repellent activity of the essential oils from callistemon viminalis, Melaleuca leucadendron, and Hyptis suaveolens against chrysodeixis chalcites and to compare it with neem oil(Azadirachta indica). Methods: The essential oils of the leaves of these aromatiques plants were extracted by steam distillation and contacts tests were carried out. Results: Essential oils in ethanol from callistemon viminalis showed a higher biological activity than the neem with 100% larval mortality at the concentration of 2 μg/m L for 6 h, 100% and 90% in ethanol from Melaleuca leucadendron and Hyptis suaveolens, respectively at the concentration of 4 μg/m L for 24 h. By inhalation, the essential oils from Melaleuca leucadendron and of Hyptis suaveolens were more effective with mortality rates of larvae 100% and 50% respectively at 2 μg/L air applied after 24 h. Nevertheless, the neem has shown to be a repulsive plant and anti-nutritional plant. A significant difference in the percentages of consumption between leaves treated with neem oil and the control samples was observed(Newman-Keuls test) except for Melaleuca leucadendron. conclusions: The results of the study highlight remarkable biocide, properties of tested extracts, which provides important opportunities for the development of biopesticides.

关键词： Plant extracts chemical constituents Insecticidal activity chrysodeixis

A discrete-time susceptible-infectious-recovered-susceptible model for the analysis of influenza data

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Infectious Disease Modelling 2023年第2期8卷 471-483页

作者： georges Bucyibaruta c.B.Dean Mahmoud Torabi Department of Statistics and Actuarial Science University of Waterloo200 University Ave WWaterlooONN2L 3G1Canada Department of community Health Sciences University of ManitobaWinnipegManitobaR3E 0W3Canada

We develop a discrete time compartmental model to describe the spread of seasonal influenza *** time and disease state variables are assumed to be discrete,this model is considered to be a discrete time,stochastic,Susceptible-Infectious-RecoveredSusceptible(DT-SIRS)model,where weekly counts of disease are assumed to follow a Poisson *** allow the disease transmission rate to also vary over time,and the disease can only be reintroduced after extinction if there is a contact with infected individuals from other host *** capture the variability of influenza activities from one season to the next,we define the seasonality with a 4-week period effect that may change over *** examine three different transmission rates and compare their performance to that of existing *** though there is limited information for susceptible and recovered individuals,we demonstrate that the simple models for transmission rates effectively capture the behaviour of the disease *** use a Bayesian approach for *** framework is applied in an analysis of the temporal spread of influenza in the province of Manitoba,canada,2012e2015.

关键词： Discrete-time epidemic model Infectious diseases Influx process Non-linear stochastic dynamics Seasonal influenza SIRS model Transmission parameter

A New Method for the Determination of cyanide Ions and Their Quantification in Some Senegalese cassava Varieties

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American Journal of Analytical chemistry 2014年第3期5卷 181-187页

作者： Younoussa Diallo Momar Talla Gueye cheikh Ndiaye Mama Sakho Amadou Kane Jean Paul Barthelemy georges lognay Département Génie chimique et Biologie Appliquée Ecole Supérieure Polytechnique Université Cheikh Anta Diop de Dakar Dakar Sénégal Institut de Technologie Alimentaire Route des Pères Maristes Dakar Sénégal Unité Analyses Qualité Risques et Laboratoire de Chimie Analytique Gembloux Agro-Bio Tech Université de Liège Gembloux Belgique

cassava (Manihot esculenta crantz) is a starchy staple food that previous researches have showed to contain cyanogenic compounds, precursors of hydrocyanic acid, undoubtedly toxic for humans. With the aim to determine food security in cassava, this study developed a simple, fast and less expensive step for quantifying cyanide ions by using micro-diffusion with modified conway cells. After an enzymatic degradation, the cyanide ions were quantified by electrochemical procedures. The validation of this method is estimated. The concentration of cyanide ions at different part of the samples was determined. The results showed high toxicity in some fresh Senegalese consumed cassava varieties (>100 mg HcN·kg﹣1). However, in the processed cassava products, less than 10 mg HcN·kg﹣1 was found in the different varieties studied except for the chips where the levels of cN﹣ contents were important (>49 mg HcN·kg﹣1).

关键词： cassava cyanogenic Glycosides cyanide Ion Micro-Diffusion Toxicity

EFFEcT OF A PROPELLER AND GAS DIFFUSION ON BUBBLE NUcLEI DISTRIBUTION IN A LIQUID

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Journal of Hydrodynamics 2012年第6期24卷 809-822页

作者： HSIAO chao-Tsung cHAHINE georges L. DYNAFLOW INC.

A multi-bubble dynamics code accounting for gas diffusion in the liquid and through the bubble wall was developed and used to study the modification of a bubble nuclei population dynamics by a propeller. The propeller flow field was obtained using a Reynolds-Averaged Navier-Stokes （RANS） solver and bubble nuclei populations were propagated in this field. The numerical procedure enabled establishment of the possibility of production behind the propeller of relatively large visible bubbles starting from typical ocean nuclei size distributions. The resulting larger bubbles are seen to cluster in the blade wakes and tip vortices. Parametric investigations of the initial nuclei size distribution, the dissolved gas concentration, and the cavitation number were conducted to ide- ntify their effects on bubble entrainment and the resultant void fractions and bubble distribution modifications downstream from the propeller. Imposed synthetic turbulence-like fluctuations unto the average RANS flow field were also used to study the effect averaging in the RANS procedure has on the results.

关键词： gas diffusion bubble entrainment propeller