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See detailIsolation and cultivation of xylanolytic and cellulolytic Sarocladium kiliense and Trichoderma virens from the gut of the termite Reticulitermes santonensis
Tarayre, Cédric ULg; Bauwens, Julien ULg; Brasseur, Catherine ULg et al

in Environmental Science and Pollution Research (2014)

The purpose of this work was the isolation and cultivation of cellulolytic and xylanolytic microorganisms extracted from the gut of the lower termite Reticulitermes santonensis. Microcrystalline cellulose ... [more ▼]

The purpose of this work was the isolation and cultivation of cellulolytic and xylanolytic microorganisms extracted from the gut of the lower termite Reticulitermes santonensis. Microcrystalline cellulose (with and without lignin) and beech wood xylan were used as diets instead of poplar wood in order to select cellulose and hemicellulose-degrading fungi. The strain Sarocladium kiliense (Acremonium kiliense) CTGxxyl was isolated from the termites fed on xylan, while the strain Trichoderma virens CTGxAviL was isolated from the termites fed on cellulose (with and without lignin). Both molds were cultivated in liquid media containing different substrates: agro-residues or purified polymers. S. kiliense produced maximal β-glucosidase, endo-1,4-β-D-glucanase, exo-1,4-β-D-glucanase and endo-1,4-β-D-xylanase activities of 0.103, 3.99, 0.53, and 40.8 IU/ml, respectively. T. virens produced maximal β-xylosidase, endo-1,4-β-D-glucanase, exo-1,4-β-D-glucanase, and endo-1,4-β-D-xylanase activities of 0.38, 1.48, 0.69, and 426 IU/ml. The cellulase and the xylanase of S. kiliense, less common than T. virens, were further investigated. The optimal activity of the xylanase was observed at pH 9–10 at 60 °C. The cellulase showed its maximal activity at pH 10, 70 °C. Zymography identified different xylanases produced by both molds, and some fragment sizes were highlighted: 35, 100, and 170 kDa for S. kiliense and 20, 40, 80, and 170 kDa for T. virens. In both cases, endo-1,4-β-D-xylanase activitieswere confirmed through mass spectrometry. [less ▲]

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See detailHarmonia axyridis population study in agroecosystems
Vandereycken, Axel ULg; Fassotte, Bérénice ULg; Durieux, Delphine ULg et al

Poster (2014, October)

The Multicoloured Asian ladybird, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), is one of these species which was intentionally introduced for biological control and has spread from its native ... [more ▼]

The Multicoloured Asian ladybird, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), is one of these species which was intentionally introduced for biological control and has spread from its native range in Central and Eastern Asia to large parts of North and South America, Europe, and Africa. The decline of native species is linked to the spread and the aggressive behaviour of H. axyridis. From 2009, we evaluated the population densities of aphids predator and predator diversities, with a special focus on H. axyridis in agroecosystems of Wallonia (South of Belgium). First, field crops preferences of H. axyridis were determined. Later, changes linked to aphid’s predator populations over time were evaluated. Finally, H. axyridis population changes between two crop farming methods were also evaluated. Samplings performed in agroecosystems highlighted that the community of aphid's predator is composed of few dominant species: three coccinellids (Coccinella septempunctata L., P. quatuordecimpunctata L., and H. axyridis), one syrphid (Episyrphus balteatus De Geer), and one chrysopid (Chrysoperla carnea Stephens). We demonstrated that H. axyridis do not invade all crops at the same rate, maize and broad bean being more infested than wheat and potato at both larval and adult stages. Moreover, H. axyridis populations in maize have strongly increased from 2009 to 2011. Finally, we showed that organic farming do not contribute to increase the abundance of H. axyridis but leads to increase the total abundance of aphid’s natural enemies. [less ▲]

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See detailStudy of sex ratio and morphotypes of the Multicoloured Asian Ladybird, Harmonia axyridis Pallas in Belgian maize
Vandereycken, Axel ULg; Fassotte, Bérénice ULg; Barsics, Fanny ULg et al

Poster (2014, October)

Several insect species are known to have different morphotypes, an adaptation to heterogeneities in changing environments. This phenotypic plasticity could be a factor used by the Multicoloured Asian ... [more ▼]

Several insect species are known to have different morphotypes, an adaptation to heterogeneities in changing environments. This phenotypic plasticity could be a factor used by the Multicoloured Asian Ladybird, which is considered as an invasive species in Europe since its introduction in the 80’s. Harmonia axyridis has four major morphotypes: 2 melanic forms, conspicua and spectabilis; and 2 non-melanic, succinea and axyridis. In Belgium, only the three first are observed. Literature reports variations in morphotype frequencies, across native and introduced strains. These variations seem to be linked to climate (geographical and seasonal variation), with non-melanic forms being the most abundant in hot and arid climate. This study focused on the variation of morphotype abundance in H. axyridis according to season, field and gender. Adult ladybirds were caught from mid-July to mid-October 2012 into 5 maize fields. The proportions of observed morphotypes were compared according to the sampling season. The abundance of morphotypes was not significantly different through the fields; the observed ratios were 81.6%, 15% and 3.4% for succinea, spectabilis and conspicua respectively. Succinea was the most observed morphotype (χ2=755.8; P<0.001). The total number of collected males and females was the same with ratios of 48.2% and 51.8%: (χ2=0.93; P=0.33). The sex ratio was also not significantly different for each morphotype. There was no evolution of melanic and non-melanic form ratio according to the season, with 25.6% of melanic form in summer and 20.6% in autumn (χ2=1.22; P=0.27). Our results seem to show that morphotype adaptation according to the climate is not observed for Belgian ladybirds. [less ▲]

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See detailUne phéromone sexuelle chez la coccinelle asiatique, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae)
Fassotte, Bérénice ULg; Fischer, Christophe ULg; Durieux, Delphine ULg et al

Conference (2014, October)

A ce jour, aucune phéromone sexuelle n’a pu être mise en évidence chez les Coccinellidae. Cependant, diverses études suggèrent que de telles molécules sont impliquées dans la communication sexuelle chez ... [more ▼]

A ce jour, aucune phéromone sexuelle n’a pu être mise en évidence chez les Coccinellidae. Cependant, diverses études suggèrent que de telles molécules sont impliquées dans la communication sexuelle chez les coccinelles. Afin de vérifier cette hypothèse, nous avons collecté les composés organiques volatils émis par la coccinelle asiatique, Harmonia axyridis (Pallas), en présence ou en absence de pucerons. En présence de pucerons, les femelles vierges présentent un « comportement d’appel » qui est notamment associé à l’émission d’une phéromone sexuelle volatile chez plusieurs espèces de Coléoptères. D’autre part, des tests éthologiques ont démontré que les femelles émettent des composés volatils qui attirent les mâles à distance. Enfin, les prélèvements ont été analysés par chromatographie en phase gazeuse couplée à la spectrométrie de masse. Les analyses ont mis en évidence cinq composés volatils spécifiques provenant des femelles, aucun d’entre eux n’étant émis pas les mâles. L’identification a révélé la présence de (–)-β-caryophyllène, de β-élémène, de méthyl-eugénol, d’α-humulène et d’α-bulnésène, exclusivement produits par les femelles nourries de pucerons et dont les quantités respectives augmentent progressivement au cours de la période de prélèvement. Les résultats confirment donc que les femelles H. axyridis produisent une phéromone sexuelle volatile. Ceux-ci devraient permettre de promouvoir le développement de méthodes de gestion plus efficaces afin de manipuler les mouvements de cette coccinelle invasive et de réduire les impacts négatifs qu’elle occasionne sur la biodiversité. [less ▲]

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See detailEvolution des populations de coccinelles indigènes et de l’espèce exotique, Harmonia axyridis Pallas, en Wallonie et en Région de Bruxelles-Capitale
Vandereycken, Axel ULg; Fassotte, Bérénice ULg; Durieux, Delphine ULg et al

Conference (2014, October)

Un inventaire des Coccinellidae provenant de la collection de l’unité d’Entomologie fonctionnelle et évolutive (ULg - Gembloux Agro-Bio Tech) a été réalisé sur une période s’étendant de 2001 à 2009. Cette ... [more ▼]

Un inventaire des Coccinellidae provenant de la collection de l’unité d’Entomologie fonctionnelle et évolutive (ULg - Gembloux Agro-Bio Tech) a été réalisé sur une période s’étendant de 2001 à 2009. Cette collection est essentiellement constituée de récoltes fournies par les étudiants de première Bachelier de Gembloux Agro-Bio Tech. A travers ce recensement, nous avons étudié l’évolution des espèces récoltées au sein de cette famille, en termes d’effectif relatif et de richesse spécifique. Notre étude s’est focalisée sur les données issues de Wallonie et de la Région de Bruxelles-Capitale, car trop peu de collectes ont été réalisées en Flandre. Parmi les individus identifiés, 27 espèces ont été observées, dont 21 appartiennent à la sous-famille des Coccinellinae, 2 à celle des Epilachninae et 4 à celle des Chilocorinae. La plupart des espèces sont communes à la Belgique. Cependant, Harmonia axyridis (Pallas 1773), espèce originaire du sud-est de l’Asie, a été introduite sur le territoire belge en 1997. Cette coccinelle exotique a fait son apparition dans les collectes de 2002 et son effectif ne cesse d’augmenter au fil des années prospectées. En parallèle à cette augmentation, une diminution de la richesse spécifique, ainsi que de l’effectif relatif d’Adalia bipunctata (L. 1758), de Propylea quatuordecimpunctata (L. 1758) et de Psyllobora vigintiduopunctata (L. 1758), est observée. [less ▲]

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See detailLarval development sites of the main Culicoides species (Diptera: Ceratopogonidae) in northern Europe and distribution of coprophilic species larvae in Belgian pastures
Zimmer, Jean-Yves ULg; Brostaux, Yves ULg; Haubruge, Eric ULg et al

in Veterinary Parasitology (2014), 205(3-4), 676-686

Some Culicoides species of biting midges (Diptera: Ceratopogonidae) are biological virus vectors worldwide and have indeed been associated with outbreaks of important epizoonoses in recent years, such as ... [more ▼]

Some Culicoides species of biting midges (Diptera: Ceratopogonidae) are biological virus vectors worldwide and have indeed been associated with outbreaks of important epizoonoses in recent years, such as bluetongue and Schmallenberg disease in northern Europe. These diseases, which affect domestic and wild ruminants, have caused considerable economic losses. Knowledge of substrates suitable for Culicoides larval development is important, particularly for the main vector temperate species. This study, realized during two years, aimed to highlight the larval development sites of these biting midge species in the immediate surroundings of ten Belgian cattle farms. Moreover, spatial distribution of the coprophilic Culicoides larvae (C. chiopterus and C. dewulfi) within pastures was studied with increasing distance from farms along linear transects (farm–pasture–woodland). A total of 4347 adult specimens belonging to 13 Culicoides species were obtained by incubation of 2131 soil samples belonging to 102 different substrates; 18 of these substrates were suitable for larval development. The Obsoletus complex (formed by two species) was observed in a wide range of substrates, including silage residues, components of a chicken coop, dung adhering to walls inside stables, leftover feed along the feed bunk, a compost pile of sugar beet residues, soil of a livestock trampling area, and decaying wood, while the following served as substrates for the other specimens: C. chiopterus, mainly cow dung; C. dewulfi, cow dung and molehill soil; C. circumscriptus, algae; C. festivipennis, algae and soil in stagnant water; C. nubeculosus, algae and silt specifically from the edge of a pond; C. punctatus, mainly wet soil between silage reserves; C. salinarius, algae; and C. stigma, algae and wet soil between silage reserves. We also recorded significantly higher densities of coprophilic larvae within pastures in cow dung located near forests, which is likely due to the localization of potential hosts; the presence of these larvae within cow dung is, however, uninfluenced by relative distance from farms. A better knowledge of the microhabitats of Culicoides biting midges and their spatial distribution may allow the development of targeted species-specific vector control strategies, and may help to prevent the creation of new larval development sites. [less ▲]

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See detailMultidisciplinary approaches and fractionations to study lower termite symbiotic system and ligno-cellulose digestion
Bauwens, Julien ULg; Brasseur, Catherine ULg; Tarayre, Cédric ULg et al

Poster (2014, August)

Wood-feeding termites are a considerable source of enzymes active on ligno-cellulosic compounds. These enzymes are produced by the termite host and some representatives of its symbiotic microbial ... [more ▼]

Wood-feeding termites are a considerable source of enzymes active on ligno-cellulosic compounds. These enzymes are produced by the termite host and some representatives of its symbiotic microbial community, and are of particular interest in regard second generation biofuel. However, the complexity of microbial interactions renders micro-organisms isolation very difficult. Culture-independent methods permitted to gather a large amount of data and to understand a little more the role of each microbial population, particularly the prokaryotes. Proteomics allows working on the final product of gene expression, and corresponds more to the real operation of the digestive system. In order to investigate such a complex system, it is necessary to use multidisciplinary approaches and to fractionate this system. Zymography or affinity chromatography are used in parallel of routine proteomics techniques such as two-dimensional gel electrophoresis associated to MALDI-TOF mass spectrometry and nano-LC ESI-MS/MS. We used an artificial-diet based rearing to induce changes in microbial population balance. We performed preliminary assay to investigate the glycosylated proteome in the hindgut of a lower termite, using Multi-Lectin Affinity Chromatography (M-LAC) and enzymatic activity of harvested fractions was assessed on cellulosic substrates. [less ▲]

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See detailInsect pests occurring on Dacryodes edulis (Burseraceae) in rural areas in Gabon
Poligui, René Noël ULg; MOUARAGADJA, ISAAC; Vandereycken, Axel ULg et al

in Neotropical Entomology (2014), 43(4), 322-334

The inventory of pests occurring on Dacryodes edulis (Burseraceae) was carried out in rural areas in Gabon during 2009 and 2010. Yellow traps and visual observations were used to record weekly pests ... [more ▼]

The inventory of pests occurring on Dacryodes edulis (Burseraceae) was carried out in rural areas in Gabon during 2009 and 2010. Yellow traps and visual observations were used to record weekly pests during the tree flowering stage, in five villages. Catches from yellow traps rose to 7,296 and 1,722 insect pests in 2009 and 2010, respectively, whereas records from visual observations corresponded to 1,812 and 171 insect pests in 2009 and 2010, respectively. During both years, abundance from traps and visual monitoring was significantly different between sampling sites (p<0.05). The difference in pests’ diversity between sampling sites was not significant (p>0.05) according to traps, but significant (p≤0.04) according to visual observations in 2010. Mecocorynus loripes Chevrolat (Coleoptera: Cucurlionidae) attacked the stem of D. edulis, while Oligotrophus sp. (Diptera: Cecidomyiidae), Pseudophacopteron serrifer Malenovsky and Burckhardt (Hemiptera: Phacopteronidae), and Selenothrips rubrocinctus Giard (Thysanopera: Thripidae) attacked leaves. Pseudonoorda edulis Maes and Poligui (Lepidoptera: Crambidae) and Lobesia aeolopa Meyrick (Lepidoptera: Tortricidae) infested fruits and inflorescences, respectively. These insects are specifically linked to plant patterns, and their identification provided the first basic information for developing suitable strategies to control pests of D. edulis in Gabon, as well as in neighboring central African countries. [less ▲]

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See detailEffects of tillage practices and crop residue exportation on earthworm communities and soil physico-­chemical properties in silt loam arable soil (Belgium)
Lemtiri, Aboulkacem ULg; Colinet, Gilles ULg; Alabi, Taofic ULg et al

Poster (2014, June 08)

Earthworms are known to play integral roles in soils, and are often referred to as vital soil and ecosystem engineers due to their capacity to influence a wide range of chemical, physical, and biological ... [more ▼]

Earthworms are known to play integral roles in soils, and are often referred to as vital soil and ecosystem engineers due to their capacity to influence a wide range of chemical, physical, and biological properties of soil environments. Therefore, it is important to understand how earthworm communities are impacted by tillage systems and crop management practices. In the present study, earthworm and soil samples were collected from wheat cultivated fields in Gembloux, Belgium under the following four experimental treatments: (1) conventional tillage with crop residues left in the soil (CT/IN); (2) conventional tillage with crop residues removed from the field (CT/OUT); (3) reduced tillage with crop residues left in the soil (RT/IN); and (4) reduced tillage with crop residues removed from the field (RT/OUT). The different tillage systems were applied for four consecutive years prior to the initiation of the current study. Results indicated soil compaction was significantly higher in RT compared with CT up to a depth of 6–49 cm. Significant differences were not detected between residue incorporation depth systems, where results showed mean earthworm abundance was respectively 182.25 and 180 individuals.m-2 in CT and RT. Mean earthworm biomass was similarly not significantly different between CT and RT, where results were respectively 48.52 and 57.27 g.m-2. However, a significant difference was observed between IN and OUT treatments, suggesting the exportation of wheat residues will limit earthworm abundance and biomass in CT and RT plots. Data showed high representation of the endogeic earthworm ecological category, notably N. c. caliginosus regardless of treatment. Despite tillage system and exportation of crop residues, N. c. caliginosus, L. terrestris, and A. r. rosea exhibited high abundance, indicating tolerance to soil environmental conditions. For each depth, measures of soil physico-chemical properties showed significant differences among treatments. Furthermore, soil chemical property attributes were significantly higher in the first soil centimetres compared to lower soil layers. These results were attributable to earthworm activity and wheat residues, suggesting earthworms contributed to nutrient dynamics, particularly at increased soil depths. Overall, the results emphasise the influence of exportation of crop residues on earthworm community and also, the important influence of earthworm activity on soil physico-chemical properties change, processes which are closely linked. [less ▲]

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See detailIs Contact Between Conspecifics Involved in the Cohesion of Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) Aggregations?
Durieux, Delphine ULg; Fassotte, Bérénice ULg; Fischer, Christophe ULg et al

in Journal of Insect Behavior (2014), 27(1), 1-13

The multicolored Asian ladybeetle, Harmonia axyridis (Pallas), exhibits a gregarious behavior during unfavorable winter conditions. Although this behavior is currently described as a phenomenon occurring ... [more ▼]

The multicolored Asian ladybeetle, Harmonia axyridis (Pallas), exhibits a gregarious behavior during unfavorable winter conditions. Although this behavior is currently described as a phenomenon occurring only during winter, aggregations can also be observed outside overwintering conditions. However, the substrate markings previously highlighted as being involved in the wintry aggregation of this exotic species do not seem to be used by non-overwintering individuals to aggregate. This fact suggests then that other cues are responsible for the induction of this behavior. In this work, we have tested the hypothesis that direct contact between non-overwintering individuals stimulates the establishment of clusters. Binary choice experiments highlighted the involvement of elytral cuticular compounds in this phenomenon. Chromatographic analyses showed that the active extracts contained mainly hydrocarbons, including saturated, mono-unsaturated, and di-unsaturated homologues. Physical contact also seems to be involved in the non-overwintering aggregative behavior of H. axyridis, but to a lesser extent than these natural compounds. These findings could eventually be used to develop new control methods of these pest populations and so, reduce the adverse impacts it causes on biodiversity. [less ▲]

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See detailInhibitors of glycosylhydrolases as potential insecticides : focus on aphid model
Bosquée, Emilie ULg; Vandermoten, Sophie; Richel, Aurore ULg et al

Poster (2014, June)

Beside conventional neurotoxic compounds, new kinds of insecticides are investigated and new specific targets are in current research. According to the energy metabolic pathway, several enzymes are ... [more ▼]

Beside conventional neurotoxic compounds, new kinds of insecticides are investigated and new specific targets are in current research. According to the energy metabolic pathway, several enzymes are interesting to bring potential specific control of arthropods. Indeed, glycosylhydrolase group is very diversified from glucanases to trehalases, until chitinases. Different kinds of inhibitors were here tested to determine their potential role as new targetted aphicides. After different assays using the selected inhibitors in artificial diets, the most efficient molecules at 50-100 μg ml-1were kept for further proteomic tasks. The proteome patterns of aphids related to different inhibitor treatments were determined by two dimension electrophoresis, 2D-Differencial In Gel Expression (2D-Dige) coupled with mass spectrometry (ESI-MS-MS and Maldi-Tof-MS-MS) and data bank investigations. Particular proteins of interest were selected and accurately characterised with both fundamental but also applied views. Not only the carbohydrate metabolic pathway was disturbed with the use of glycosylhydolases inhibitors, other primary functions were also modified (amino acid synthesis, stress response, etc). This proteomic approach was discussed as an interesting and reliable tool to study the biologically involved proteins from aphids in response to specific tested enzymatic inhibitors with further ideas to be promoted as new insecticides to control insect pests. [less ▲]

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See detailBelowground Chemical Ecology: The Case of Wireworms
Barsics, Fanny ULg; Delory, Benjamin ULg; Delaplace, Pierre ULg et al

Poster (2014, June)

Wireworms, clock-beetles' larvae (Coleoptera, Elateridae), are below ground pests of many crops. They cause dramatic yield losses worldwide. Research on their ecology is crucial to undertake innovative ... [more ▼]

Wireworms, clock-beetles' larvae (Coleoptera, Elateridae), are below ground pests of many crops. They cause dramatic yield losses worldwide. Research on their ecology is crucial to undertake innovative management strategies. In the field of chemical ecology, multitrophic interactions occurring in the rhizosphere are gaining increasing attention from entomologists and agronomists. Our research aims at unveiling the role of volatile organic compounds (VOC) involved in wireworms' foraging behavior, putatively leading to host localization and/or host recognition. [less ▲]

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See detailIs conspecific substrate marking a long-term external memory of previously colonized overwintering sites in Harmonia axyridis?
Durieux, Delphine ULg; Fassotte, Bérénice ULg; Vanderplanck, Maryse et al

in Journal of Applied Entomology (2014), 138(5), 338-345

The multicoloured Asian ladybeetle, Harmonia axyridis (Pallas), aggregates inside dwellings during winters to survive the cold. This beetle uses chemical cues coming from congeners to select an ... [more ▼]

The multicoloured Asian ladybeetle, Harmonia axyridis (Pallas), aggregates inside dwellings during winters to survive the cold. This beetle uses chemical cues coming from congeners to select an overwintering site. Recent research has shown that they preferentially gather at places where conspecifics previously laid a substrate marking made up of saturated and unsaturated hydrocarbons. Some authors have reported that H. axyridis colonizes the same overwintering sites from 1 year to another. Herein, the hypothesis that this substrate marking is used by H. axyridis to settle in the same aggregation sites from one winter to another was tested. To this aim, the temporal modification in the chemical profile of the hydrocarbon marking was studied by performing chromatographic analyses. After 1 year, the overall profile was modified qualitatively and quantitatively: the unsaturated hydrocarbons were no longer detected while some saturated hydrocarbons were still present in large quantities. In a behavioural assay conducted in the laboratory, the 12-month-old marking did not induce the aggregation of H. axyridis. This result indicates that the chemical markings left by conspecifics during a previous aggregation period in an overwintering site are not sufficient to induce the gathering of the newly arriving individuals. [less ▲]

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See detailSynthèse bibliographique : l'écologie larvaire des culicoïdes (Diptera : Ceratopogonidae)
Zimmer, Jean-Yves ULg; Haubruge, Eric ULg; Francis, Frédéric ULg

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2014), 18(2), 301-312

Cet article présente une synthèse de l’écologie larvaire des culicoïdes (Diptera : Ceratopogonidae) en vue de rassembler les connaissances, souvent très parsemées, des sites d’oviposition et des habitats ... [more ▼]

Cet article présente une synthèse de l’écologie larvaire des culicoïdes (Diptera : Ceratopogonidae) en vue de rassembler les connaissances, souvent très parsemées, des sites d’oviposition et des habitats larvaires actuellement identifiés à travers le monde pour les principales espèces de culicoïdes. Ces moucherons piqueurs hématophages sont impliqués dans la transmission de divers parasites (protozoaires et filaires) et virus aux animaux. Le développement larvaire des culicoïdes est généralement optimal dans les substrats humides et riches en débris organiques divers. Cependant, chaque espèce présente ses propres exigences écologiques et se trouve par conséquent dans des micro-habitats spécifiques. Dans cette synthèse, les gites larvaires sont répartis en substrats aquatiques et semi-aquatiques d’eau douce et d’eau salée ou saumâtre, substrats terrestres et substrats anthropiques liés à l’élevage. Les gites larvaires de nombreuses espèces appartenant au genre Culicoides Latreille demeurent cependant encore méconnus. La connaissance de ces derniers et leur caractérisation sont pourtant essentielles pour permettre la mise au point de stratégies de lutte efficaces contre ces insectes vecteurs, permettant ainsi de renforcer la vaccination du bétail et les autres moyens de lutte mis en oeuvre. Les habitats larvaires actuellement identifiés pourraient permettre d’orienter les investigations des recherches écologiques futures et les propositions de contrôle de ces moucherons vecteurs. [less ▲]

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See detailFive Years of aphidophagous species sampling in belgian corn
Vandereycken, Axel ULg; Fassotte, Bérénice ULg; Durieux, Delphine ULg et al

Poster (2014, May 20)

The community of aphidophagous species present in agroecosystems is disturbed since the introduction of an exotic species the Multicoloured Asian Ladybird, Harmonia axyridis Pallas (Coleoptera ... [more ▼]

The community of aphidophagous species present in agroecosystems is disturbed since the introduction of an exotic species the Multicoloured Asian Ladybird, Harmonia axyridis Pallas (Coleoptera: Coccinellidae). In this intensive agricultural area, five aphids predator species are commonly observed: three coccinellids H. axyridis, Coccinella septempunctata, Propylea quatuordecimpunctata, one hoverfly Episyrphus balteatus, and one lacewing Chrysoperla carnea. This study focuses on the occurrence of the five most abundant aphid predators and their seasonal abundance in corn. The abundance of adults and larvae of these species was evaluated over a five-year period, from 2009 to 2013. The sampling method consisted in the counting of aphids and all developmental stages of aphidophages present in quadrats of 1m² from April to November. Densities of aphid predators changed during five years studies. Since 2011, H. axyridis was the most abundant aphids predators in corn. H. axyridis numbers were found to increase over the first four inventoried year, reaching in 2012 86% for adult stage (119,7±7,8 adults/100m2) and 76% for larvae stages (242,8±14,2 larvae/100m2) of the aphid predators, while in 2009 these ratios were 14% and 23% respectively. For C. septempunctata and P. quatuordecimpunctata the population densities decrease at the end of the five years period. Population densities of C. carnea and E. balteatus were variable during the sampling period but increased in 2013. Phenology of the five studied species presents similar curves following the aphid abundance. The most abundant observed aphids were metopolophium dirhodum, rhopalosiphum padi, rhopalosiphum maidis, sitobion avenae and sitobion fragariae. H. axyridis starts reproducing after the peak in aphid population, suggesting that H. axyridis is able to complete its development by feeding on alternative prey such as larvae and pupae of conspecific and heterospecific. H. axyridis is a bivoltine species but the second generation was stop by the corn harvesting. [less ▲]

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See detailMealworms: Alternate Source of Lipids
Danthine, Sabine ULg; Blecker, Christophe ULg; Paul, Aman ULg et al

Scientific conference (2014, May 16)

The aim of present study was to determine the physicochemical properties of the oil obtained from Tenebrio molitor larvae (mealworms) and explore its potential as edible oil. Five batches of Tenebrio ... [more ▼]

The aim of present study was to determine the physicochemical properties of the oil obtained from Tenebrio molitor larvae (mealworms) and explore its potential as edible oil. Five batches of Tenebrio molitor larvae were investigated for their lipid content and physiochemical properties. Three batches were reared in lab (3 different productions) and two were purchased from a local supplier. The lipids were extracted using a cold extraction technique employing 2:1 ratio chloroform/methanol as solvent. The fatty acid profile was determined using gas chromatography and triacylglycerol profile using HPLC. The thermal properties of the lipid extracts were also analyzed using differential scanning calorimetry. All the samples contained high amount of unsaturated fatty acids. The chemical composition and the thermal properties of the samples varied with the source. With this quantity and quality of lipid content, mealworms offer potential as an important source of edible lipids. [less ▲]

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See detailBelgian Grasshoppers: A Nutritious Food Source
Paul, Aman ULg; Frederich, Michel ULg; Blecker, Christophe ULg et al

Poster (2014, May 14)

Rapid urbanization and rising economies are creating shifts in the composition of global food demand, so it is necessary to explore new sources of food with better nutritional profile. Among the ... [more ▼]

Rapid urbanization and rising economies are creating shifts in the composition of global food demand, so it is necessary to explore new sources of food with better nutritional profile. Among the alternative food that exists are the grasshoppers, about 80 species of which are consumed worldwide. Grasshoppers are not only rich source of proteins and lipids but also some important minor component like vitamins and minerals. Edible species of grasshopper in Belgium were identified and attempts were made for the lab rearing of meadow grasshopper (Chorthippus parallelus). The lipids as well as protein contents of meadow grasshopper (Chorthippus parallelus) & long winged conehead (Conocephalus discolor) were investigated. The fatty acid compositions of these two species were determined by gas chromatography. Some of the physicochemical properties of the lipids extracted were also analyzed. These two grasshopper species could be really nutritious source of food. [less ▲]

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See detailLocusts and Grasshoppers: Future Foods?
Paul, Aman ULg; Frederich, Michel ULg; Uyttenbroeck, Roel ULg et al

Scientific conference (2014, May 08)

Consuming locusts and grasshoppers as food is not a new concept, because some people have been doing it for a long time and there are many references in the religious literature to support this. About 80 ... [more ▼]

Consuming locusts and grasshoppers as food is not a new concept, because some people have been doing it for a long time and there are many references in the religious literature to support this. About 80 locust and grasshopper species are consumed worldwide, and the large majority of grasshopper species are edible. From the nutritional point of view they are an excellent source of proteins, lipids and other minor components like vitamins and minerals. They are an excellent source of amino acids and their lipids contain a large majority of unsaturated fatty acids. Environmentalists have supported human consumption of grasshoppers owing to the facts that they usually appear as pests. Using them as food could help reduce their population and result in limited application of harmful pesticides. Their production usually generates lesser amount of greenhouse gases & ammonia; a lower amount of water is required for their production in comparison to conventional proteins sources. Some species of grasshoppers usually feed on dead organic matter, this reduces the environmental load. In the developing world, catching of grasshoppers and selling them for human consumption has played a key role in improving the livelihood of women and underprivileged children. Eating grasshopper and locust is not a very common practice in temperate areas. However it is a very common practice in the tropical areas of world because of the higher density, bigger size of the insect and yearlong availability in such areas. To encourage their consumption in temperate areas, it is now necessary to perform accurate research regarding food safety (minor components, toxicity, allergens,…) but also to develop value added products to make it easier for people to adapt with entomophagy. Furthermore we have to develop methods for commercial production and organize awareness campaigns to explain about the nutritional and other benefits related to locust & grasshopper consumption as food to people. [less ▲]

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