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

Poster (2014, April 02)

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 corn 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. We discuss these results according to all environmental data available. [less ▲]

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See detailWill top-down interactions be affacted by climate change?
Boullis, Antoine ULg; Verheggen, François ULg; Francis, Frédéric ULg

Poster (2014, April 02)

Greenhouse gas emissions are rising since the beginning of the industrial era: atmospheric carbon dioxide now exceeds 400 ppm (30% increase since the mid-1800s) and tropospheric ozone has reached 40 ppb ... [more ▼]

Greenhouse gas emissions are rising since the beginning of the industrial era: atmospheric carbon dioxide now exceeds 400 ppm (30% increase since the mid-1800s) and tropospheric ozone has reached 40 ppb in industrialized areas. According to forecasting models, these concentrations are expected to double by the end of the 21st century. To date, impacts of elevated greenhouse gases have been extensively studied in plant-insect interactions, whereas interactions between herbivores and their natural enemies have been neglected. Because most interactions between herbivorous insects and their natural enemies are orchestrated by natural molecules produced as semiochemicals, we hypothesize that modification in atmospheric gas composition will alter chemical communication in insects, and affect the performance of natural enemies to locate their prey. In this project, we shall attempt to analyze the effect of increase in greenhouse gas concentrations on insect communication, particularly in top-down interactions. The study model will consist in the interactions between the pea aphids (Acyrthosiphon pisum (Harris)) and their natural enemies Harmonia axyridis (Pallas) and Episyrphus balteatus (DeGeer). Under elevated CO2 and/or O3 concentrations, we will quantify the production of several aphid semiochemicals that are currently used as kairomones by natural enemies, including the aphid alarm pheromone E-β-farnesene and honeydew volatile compounds. Olfactometry assays will then be set up to examine the ability of natural enemies to locate their prey in the predicted atmospheric conditions of the end of the 21st century. Finally, using an Ecotron structure to be built in Gembloux Agro-Bio Tech, we will simulate a future ecosystem with the possibility to control additional biotic and abiotic parameters. [less ▲]

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See detailFirst evidence of a volatile sex pheromone in the invasive Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae)
Fassotte, Bérénice ULg; Fischer, Christophe ULg; Durieux, Delphine ULg et al

Conference (2014, April 02)

Data about sex pheromones, or any semiochemicals that play a role in Coccinellid mating, remain limited. Since years, various studies and behavioral observations have hypothesized that such molecules are ... [more ▼]

Data about sex pheromones, or any semiochemicals that play a role in Coccinellid mating, remain limited. Since years, various studies and behavioral observations have hypothesized that such molecules are involved in sexual communication of ladybeetles. In this study, we collected volatile organic compounds released by virgin females of the multicolored Asian ladybeetle, Harmonia axyridis (Pallas), which were either allowed or not allowed to feed on aphids. In the presence of aphids, virgin females exhibited “calling behavior”, which has been associated with the emission of a sex pheromone in several Coleoptera species. Bioassays showed that these females released a blend of volatile compounds that is involved in the attraction of males. Gas Chromatography-Mass Spectrometry analyses highlighted specific volatile cues emanating from females, whereas males did not produce these compounds. Five components were identified: (–)-β-caryophyllene, β elemene, methyl-eugenol, α humulene, and α bulnesene. All compounds were produced after virgin females were fed aphids, and their quantity increased across the experimental period. The results confirm that female H. axyridis produce a volatile sex pheromone. Therefore, this study provides important biological information that could promote the development of efficient pest control management methods to manipulate the movements of this invasive ladybeetle, and to reduce its negative impacts on biodiversity. [less ▲]

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See detailA pheromone-based formulation against phytophagous pests
Fassotte, Bérénice ULg; Vandereycken, Axel ULg; Heuskin, Stéphanie ULg et al

Poster (2014, April 02)

Innovative integrated pest management methods are needed to overcome market withdrawal of synthetic pesticides. Therefore, the identification of environment-friendly bio-products carrying direct or ... [more ▼]

Innovative integrated pest management methods are needed to overcome market withdrawal of synthetic pesticides. Therefore, the identification of environment-friendly bio-products carrying direct or indirect biocide activity is one promising alternative option. Our researches focus on the identification of appropriate formulations releasing volatile organic compounds that are attractive for natural enemies of insect pests. However, the elaboration of slow-release devices that ensure stable and controlled release of active volatile compounds is quite challenging. Here, we developed a formulation based on E-β-farnesene and (–)-β-caryophyllene, these two semiochemicals having strong attractive potential on aphid natural enemies including ladybeetles and hoverflies. Both compounds were encapsulated together in alginate gel beads. The blend efficiency is currently being evaluated through laboratory and field assays. [less ▲]

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See detailMacrolophus pygmaeus (Rambur) as an efficient predator of the tomato leafminer Tuta absoluta (Meyrick) in Europe. A review
De Backer, Lara ULg; Caparros Megido, Rudy ULg; Haubruge, Eric ULg et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2014)

The tomato leafminer, Tuta absoluta (Meyrick), originates from South America, and remains one of the main tomato pests in this continent. Since its introduction to Europe in 2006, Mediterranean countries ... [more ▼]

The tomato leafminer, Tuta absoluta (Meyrick), originates from South America, and remains one of the main tomato pests in this continent. Since its introduction to Europe in 2006, Mediterranean countries have also been exposed to this pest. Because of the endophytic habits of the larvae and ability of adults to reproduce parthenogenetically, chemicals and sexual pheromone- based control methods generate poor results. Recently, the use of biocontrol agents, such as Macrolophus pygmaeus Rambur (Heteroptera: Miridae), has been investigated as an alternative means of control, the results of which are presented in this review. Macrolophus pygmaeus is a mirid bug that is widely used to control different phytophagous insects in integrated pest management strategies through Europe. Several studies have confirmed the high predation potential of M. pygmaeus on T. absoluta under laboratory and semi-field conditions. This predator spontaneously colonizes tomato greenhouses in the southern Mediterranean countries. The use of banker plants (i.e., plants that provide a habitat to the predator) improves the colonization ability of this natural enemy. Hence, if the local population size is low, an augmentative strategy could be adopted. Predators may be released before or after the onset of pest infestation, with recommendations varying depending on natural population densities of both the pest and predator. The efficiency of M. pygmaeus has also been evaluated when used in combination with other biocontrol agents or with chemicals. This work presents an overview of different types of control strategies using M. pygmaeus against the tomato leafminer, T. absoluta. [less ▲]

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See detailDepths and type of substrate influence the ability of Nasonia vitripennis Walker (Hymenoptera: Pteromalidae) to encounter host
Frederickx, Christine ULg; Dekeirsschieter, Jessica ULg; Verheggen, François ULg et al

in Journal of Insect Science [=JIS] (2014)

The foraging behaviour of a parasitoid insect species includes the host’s habitat and subsequent location of the host. Habitats-substrate, substrate moisture and light levels can affect the host location ... [more ▼]

The foraging behaviour of a parasitoid insect species includes the host’s habitat and subsequent location of the host. Habitats-substrate, substrate moisture and light levels can affect the host location made by different species of parasitoids. However, the depth at which parasitoids concentrate their search effort is an another important ecological characteristic and play an important role on the host location. Here, we have investigated the ability of a pupal parasitoid, Nasonia vitripennis Walker, to penetrate and kill fly pupae located at different depth of the substrate. Three different types of substrate were tested: loam soil, compost and vermiculite substrate. In both loam soil and compost, all of the parasitism activity was restricted to pupae placed directly on the surface. Parasitism activity in vermiculite showed that the average number of pupae parasitized was decreased with depth. These results suggest that fly pupae situated deeper in the substrate are less subjected to parasitism by N. vitripennis. [less ▲]

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See detailAggregation behavior of Harmonia axyridis under non-wintering conditions
Durieux, Delphine ULg; Fassotte, Bérénice ULg; Deneubourg, Jean-Louis et al

in Insect Science (2014)

The invasive multicolored Asian ladybeetle, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), aggregates inside dwellings during winter to avoid cold weather. This adaptive behavior disturbs ... [more ▼]

The invasive multicolored Asian ladybeetle, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), aggregates inside dwellings during winter to avoid cold weather. This adaptive behavior disturbs homeowners, because of the large numbers of individuals that aggregate, which induces allergic reactions. The migratory flight patterns of this species have been well documented, with individuals preferentially moving toward prominent and high color contrast elements. However, the factors involved in the selection of aggregation sites by this species have yet to be elucidated. Here, we evaluated the influence of (i) the density of individuals and (ii) the type of available shelters on decisions by H. axyridis to settle and aggregate under shelters. A dual choice bioassay conducted in the laboratory demonstrated the presence of mutual attraction to conspecifics. We also found that individuals preferentially settled under red covered shelters compared to transparent shelters, and that the type of shelter outweighed the effect of social interactions among conspecifics. Moreover, this experiment was performed under non-wintering conditions, providing the first evidence that aggregative behavior in this species can also occur under those specific conditions. [less ▲]

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See detailInfestation Level Influences Oviposition Site Selection in the Tomato Leafminer Tuta absoluta (Lepidoptera: Gelechiidae)
Bawin, Thomas ULg; De Backer, Lara ULg; Dujeu, David ULg et al

in Insects (2014), 5

The tomato leafminer, Tuta absoluta (Lepidoptera: Gelechiidae), is a devastating pest that develops principally on solanaceous plants throughout South and Central America and Europe. In this study, we ... [more ▼]

The tomato leafminer, Tuta absoluta (Lepidoptera: Gelechiidae), is a devastating pest that develops principally on solanaceous plants throughout South and Central America and Europe. In this study, we tested the influence of three levels of T. absoluta infestations on the attraction and oviposition preference of adult T. absoluta. Three infestation levels (i.e., non-infested plants, plants infested with 10 T. absoluta larvae, and plants infested with 20 T. absoluta larvae) were presented by pairs in a flying tunnel to groups of T. absoluta adults. We found no differences in terms of adult attraction for either level of infestations. However, female oviposition choice is influenced by larvae density on tomato plants. We discuss the underlying mechanisms and propose recommendations for further research [less ▲]

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See detailMicroorganism-associated semiochemicals reduce the size of aphid populations in potato fields
Alabi, Taofic ULg; Brostaux, Yves ULg; Grigorescu, Alina ULg et al

in Revue des Régions Arides (2014), 35

The chemical cues released by many insect species, including agricultural pests, are used by predators and parasitoids to locate their prey or host. For instance, aphids excrete honeydew, which contains ... [more ▼]

The chemical cues released by many insect species, including agricultural pests, are used by predators and parasitoids to locate their prey or host. For instance, aphids excrete honeydew, which contains bacteria that produce semiochemicals. Ladybeetles and hoverflies use these semiochemicals to locate the colonies of prey aphid species. One bacterium (Staphylococcus sciuri) has been identified in the honeydew of the pea aphid, Acyrthosiphon pisum. This bacterium is responsible for the production of kairomonal substances, which guide hoverflies to aphid colonies. In the present study, we cultivated S. sciuri, and used solid-phase microextraction (SPME) to confirm the ability of this bacterium to produce 3-methyl-2-butenal and 3-methyl-2-butenoic acid, which previous studies have demonstrated as being the two semiochemicals that exhibit kairomonal activity. We subsequently conducted field experiments to evaluate the efficiency of two solutions as biological products to control aphid populations inhabiting potato plants; the first solution contained a suspension of living S. sciuri, and the second solution contained a mixture of the two semiochemicals produced by this bacterium. While the semiochemical solution did not lead to a significant reduction in aphid number, potato plants treated with the S. sciuri solution were infested with 28% less aphids compared to untreated plants. This study demonstrates the potential of using naturally occurring bacteria as a form of biological control of aphid infestations in agricultural management. [less ▲]

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See detailEffet du mode de conservation d’huile de Jatropha curcas L. sur son efficacité dans la lutte contre les principaux insectes ravageurs du niébé (Vigna unguiculata (L.) Walp. au Niger
Abdoul Habou, zakari; Toudou, Adam; Haubruge, Eric ULg et al

in Tropicultura (2014), 32(4), 191-196

Jatropha curcas oil has an insecticidal activity harnessed by the farmers in Niger. In this study, we compared the insecticidal activity of two batches of oil conserved during 70 days, one exposed to ... [more ▼]

Jatropha curcas oil has an insecticidal activity harnessed by the farmers in Niger. In this study, we compared the insecticidal activity of two batches of oil conserved during 70 days, one exposed to light and the other kept in the dark. The insecticidal efficacy was evaluated in a field with three concentrations (5, 10 and 15%) trial on the main pests of Cowpea (Vigna unguiculata (L.) Walp) and in a laboratory test on Megalurothrips sjostedti Trybon (Thysanoptera: Thripidae) with different concentrations of crude oil (50; 100; 150 and 200 µl). No difference in insecticidal effect was found between the two modes of oil conservation, both in the laboratory and in the field. In the field, regardless of the mode of conservation, the concentrations of 10% of J. curcas oil enables a reduction of over than 80% of thrips, aphids, and bugs compared to the control. Its increased seeds yield more than 50%. The concentration of 15% gives an insecticidal effect comparable to that of the reference treatment (deltaméthrine) but induces phytotoxicity symptoms on the leaves of Cowpea. [less ▲]

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See detailInsecticidal effect of Jatropha curcas L. seed oil on Callosobruchus maculatus Fab and Bruchidius atrolineatus Pic (Coleoptera: Bruchidae) on stored cowpea seeds (Vigna unguiculata L. Walp.) in Niger
Abdoul Habou, Zakari; Haougui, Adamou; Basso, Adamou et al

in African Journal of Agricultural Research (2014), 9(32), 2506-2510

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See detailAVIS de l’Agence nationale de sécurité sanitaire de l’alimentation, de l’environnement et du travail relatif à « l’analyse de risques phytosanitaires portant sur Rhagoletis completa »
Verheggen, François ULg; Escobar, Abraham; Giordanengo, Philippe et al

Report (2014)

Rhagoletis completa est un insecte (Diptera : Tephritidae) nuisible listé à l’annexe I, partie A, chapitre I de la directive 2000/29/CE. À ce titre, cet organisme nuisible est également listé en annexe B ... [more ▼]

Rhagoletis completa est un insecte (Diptera : Tephritidae) nuisible listé à l’annexe I, partie A, chapitre I de la directive 2000/29/CE. À ce titre, cet organisme nuisible est également listé en annexe B de l’arrêté du 31 juillet 2000, ce qui en fait un organisme de lutte obligatoire sous certaines conditions sur tout le territoire français. En France métropolitaine, cet organisme nuisible est très largement répandu dans le bassin de production du grand sud-est où la stratégie de lutte mise en place visait à limiter sa pression. Il est également présent dans le bassin de production du grand sud-ouest (Aquitaine et Midi- Pyrénées), bien que le coeur de ce bassin de production de noix semble encore préservé. La stratégie mise en place dans cette région vise encore à limiter son extension et à protéger les zones encore exemptes. Au vu de la dispersion de R. completa dans le grand sud-est, l’Anses est saisie pour la réalisation d’une analyse de risques phytosanitaires (ARP) portant sur R. completa et ce, sur l’ensemble du territoire de l’Union Européenne. Cette ARP pourra servir de base aux discussions communautaires permettant la révision du statut de cet organisme au sein de la directive 2000/29/CE ainsi que la définition de mesures de gestion appropriées le cas échéant dans le cadre du dispositif passeport phytosanitaire européen (PPE). [less ▲]

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See detailInsects Associated With Jatropha curcas Linn. (Euphorbiaceae) in West Niger
Zakari, Abdoul Habou; Toudou, Adam; Haubruge, Eric ULg et al

in Journal of Insect Science [=JIS] (2014)

Jatropha curcas has been introduced into Niger since 2004 by International Crops Research Institute for the Semi-Arid Tropics (ICRISAT). This plant is cultivated for its oil, which can be used as a ... [more ▼]

Jatropha curcas has been introduced into Niger since 2004 by International Crops Research Institute for the Semi-Arid Tropics (ICRISAT). This plant is cultivated for its oil, which can be used as a Biofuel. Through direct and indirect insect collection methods, an inventory of the insect associated with J. curcas has been conducted in Western Niger during two rainy seasons (from June to October) in 2010 and 2011. We have identified insects belonging to the following families: Acrididae (Oedaleus senegalensis Krauss, 15 Oedaleus nigeriensis Uvarov, Heteracris leani Uvarov, Catantops stramineus Walker, Parga cyanoptera Uvarov, and Acanthacris ruficornis citrina Audinet-Serville), Pyrgomorphidae (Poekilocerus bufonius hieroglyphicus Klug), Cetoniidae (Pachnoda interrupta Olivier, Pachnoda marginata aurantia Herbst, Pachnoda sinuata Heinrich and McClain, and Rhabdotis sobrina Gory and Percheron), Meloidae (Decapotoma lunata Pallas), Pentatomidae (Agonoscelis versicoloratus Dallas, Nezara viridula Linn, and Antestia sp. Kirkaldy), Coreidae (Leptoglossus membranaceus Fabricius and Cletus trigonus Thunberg), and Scutelleridae (Calidea panaethiopica Kirkaldy). Origin and 20 potential impact on J. curcas of all these insect species are presented and discussed. The lower insect’s diversity indexes are observed in 2010 and 2011 for Niamey, Saga, and Gaya because of semi-arid character of the Sahelian area. [less ▲]

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See detailAphid honeydew: An arrestant and a contact kairomone for Episyrphus balteatus (Diptera: Syrphidae) larvae and adults
Leroy, Pascal; Almohamad, Raki; Attia, Sabrine et al

in European Journal of Entomology (2014), 111(2), 237-242

Predator searching efficiency increases in response to a variety of environmental cues associated with its prey. The sugary excretion of aphids (honeydew) has been found to act as a prey-associated cue ... [more ▼]

Predator searching efficiency increases in response to a variety of environmental cues associated with its prey. The sugary excretion of aphids (honeydew) has been found to act as a prey-associated cue for many aphid natural enemies. In the present study, the honeydew excreted by Acyrthosiphon pisum (Harris) was identified as an arrestant and a contact kairomone for young larvae and adults of a common predatory hoverfly, Episyrphus balteatus (De Geer) (Diptera: Syrphidae). First and second instar larvae increased their foraging behaviour in the honeydew-treated area. When plants were sprayed with crude honeydew, the speed of movement of female E. balteatus was significantly higher than in controls, resulting in a longer period of time spent on treated plants and laying eggs. We conclude that the honeydew excreted by A. pisum induces searching behaviour and acts as and arrestant not only for adults but also for young E. balteatus larvae. [less ▲]

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See detailRole of larval host plant experience and solanaceous plant volatile emissions in Tuta absoluta (Lepidoptera: Gelechiidae) host finding behavior
Caparros Megido, Rudy ULg; De Backer, Lara; Ettaïb, Refki et al

in Arthropod-Plant Interactions (2014)

The tomato leafminer, Tuta absoluta (Lepi- doptera: Gelechiidae), is considered to be a major pest that damages tomato (Solanum lycopersicum L; Solanaceae) crops in South American, European, and ... [more ▼]

The tomato leafminer, Tuta absoluta (Lepi- doptera: Gelechiidae), is considered to be a major pest that damages tomato (Solanum lycopersicum L; Solanaceae) crops in South American, European, and Mediterranean countries. This insect species is polyphagous (i.e., feeds on many types of food); hence, it could also develop on other cultivated host plants, principally solanaceous plants, such as potato (S. tuberosum L.; Solanaceae) and eggplant (S. melongena L.; Solanaceae). Therefore, we tested the hypothesis that host plant choice by adult T. absoluta is influenced by plant volatile organic compounds and larval host plant experience. One tomato cultivar (cv.) ‘Money- maker’ and three potato cv. ‘Charlotte’ ‘Bintje,’ and ‘Nicola’ were tested. Using a flying tunnel, we observed that females reared on tomato preferred flying toward tomato and, to a lesser extent, potato cv. ‘Charlotte.’ These preferences might be explained by the high release of terpenes by these two plants. When conducting oviposition choice assays, we found no preference between tomato and potato in the number of eggs laid by females that had been previously reared on either host plant. This study indicates that the host finding behavior of T. absoluta is mediated by solanaceous volatiles, while oviposition behavior appears to depend on additional stimuli. These results provide baseline information for use in the development of new control strategies against T. absoluta using semiochemicals and plant breeding. [less ▲]

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See detailÉvaluation du potentiel de dix accessions de Jatropha curcas L. (Euphorbiaceae) au Niger
Abdoul Habou, Zakari; Katkore, Boubacar; Abasse, Tougiani et al

in Journal of Applied Biosciences (2014), 77

Objective: A trial of the ten accessions for J curcas was carried out at regional Agricultural Research Center of Maradi in Niger, with aim to evaluate the performance of Jatropha curcas accessions ... [more ▼]

Objective: A trial of the ten accessions for J curcas was carried out at regional Agricultural Research Center of Maradi in Niger, with aim to evaluate the performance of Jatropha curcas accessions. Methodology and results: Each accession was represented by two rows and each row has 15 plant trees of J. curcas. Data on the rate of survival and growth parameters of each tree were collected. Results revealed that there is no significant difference between accessions tested for height and diameter. Accessions Katil 13 and GB 14 respectively originated from Mali and Bisseau Guinea were best adapted for the Niger conditions. The yield value of 511 and 445 kg per hectare respectively obtained from Katil 13 and GB 14 in 2012.Conclusion and application of results: The Government of Niger has drawn attention to this crop and has launched a J. curcas plantation for seed production of 150 ha at Guessalbodi. National Research Institution. NGOs are also involved in J. curcas plantation for biofuel use. [less ▲]

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See detailHost-habitat location by the parasitoid, Nasonia vitripennis Walker (Hymenoptera: Pteromalidae).
Frederickx, Christine ULg; Dekeirsschieter, Jessica ULg; Verheggen, François ULg et al

in Journal of Forensic Sciences (2014), 59

This study investigated the role of odorant cues used during host-habitat location by the generalist parasitoid, Nasonia vitripennis Walker. N vitripennis is a common parasitoid of Dipteran pupae found in ... [more ▼]

This study investigated the role of odorant cues used during host-habitat location by the generalist parasitoid, Nasonia vitripennis Walker. N vitripennis is a common parasitoid of Dipteran pupae found in association with decaying carrion. Behavioral assays were used to investigate the host-habitat searching behavior under different scenarios. First, we demonstrated N. vitripennis to be significantly attracted toward odorant cues associated with decaying meat. The biological activity of nine of the volatile molecules constituting the odor of decaying meat were tested on the searching behavior of parasitoid females through two complementary chemoecological approaches: electronantennography (EAG) and olfactometry bioassays. Butanoic acid and butan-1-ol elicited high olfactory responses, but no attraction was induced by these two chemicals. Behavioral assays showed that, among the VOCs tested, methyldisulfanylmethane (DMDS) was the only volatile chemical to induce attraction in N. vitripennis. [less ▲]

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See detailUn regard nouveau sur le mutualisme fourmis-pucerons
Verheggen, François ULg

Scientific conference (2014)

Un regard nouveau sur le mutualisme fourmis-pucerons Nombre d’homoptères producteurs de miellat ont développé des relations de mutualisme avec les fourmis. Depuis des décennies, le cas particulier des ... [more ▼]

Un regard nouveau sur le mutualisme fourmis-pucerons Nombre d’homoptères producteurs de miellat ont développé des relations de mutualisme avec les fourmis. Depuis des décennies, le cas particulier des fourmis et des pucerons est l'un des modèles de mutualisme les plus étudiés, et a captivé des générations d’entomologistes. Sans défense, les pucerons sont des proies faciles pour de nombreux ennemis naturels. Cependant, certaines espèces (dites myrmécophiles) sont observées associés à des fourmis, qui protègent leurs partenaires en échange de leur miellat, riche en sucres et acides aminés. Sédentarisme, absence de réaction agressive, omniprésence et habitudes grégaires, tous ces facteurs contribuent à faciliter leur découverte et leur contrôle par les fourmis. Mais la rencontre entre ces deux partenaires est facilitée par un troisième groupe d’organismes: des bactéries. Se développant dans le miellat, ces dernières guident, par les odeurs qu’elles produisent, les fourmis exploratrices vers la colonie de pucerons. Dans cette conférence nous présenterons les résultats de plusieurs années de recherche démontrant l’importance : (1) du rôle de protection des fourmis, (2) de la composition en sucre du miellat, (3) des phéromones aphidiennes et (4) des bactéries se développant dans le miellat, pour l’établissement et le maintien des relations de mutualisme entre fourmis et pucerons. [less ▲]

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See detailA volatile sex pheromone in the invasive ladybeetle Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae)
Fassotte, Bérénice ULg; Fischer, Christophe ULg; Durieux, Delphine ULg et al

in Communications in Agricultural and Applied Biological Sciences (2014), 79(1), 79-81

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