References of "Lorge, Stéphanie"
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See detailThe taste of origin in a lady beetle: do males discriminate between females based on cuticular hydrocarbons?
Legrand, Pauline; Vanderplanck, Maryse ULiege; Marko, Istvan et al

in Physiological Entomology (2019)

The Asian lady beetle Harmonia axyridis originates from Asia and has established invasive populations at a worldwide scale. Recent population genetic studies have traced their invasion routes and ... [more ▼]

The Asian lady beetle Harmonia axyridis originates from Asia and has established invasive populations at a worldwide scale. Recent population genetic studies have traced their invasion routes and demonstrated that bottlenecks in population size have reduced their genetic diversity. As a consequence, phenotypical differences were highlighted between native and invasive populations. Among phenotypical traits, cuticular hydrocarbons (CHCs) might reflect geographical origin of a lady beetle, especially because of their genetic basis. Here, we investigated whether (i) the CHC profiles qualitatively and quantitatively differ between females of H. axyridis from native and invasive populations; and (ii) males discriminate females from native and invasive populations using CHC profiles. CHCs were solvent-extracted before being quantified and identified by gas chromatography and mass spectrometry. We detected a total of 17 CHCs from female elytra including six alkanes, three polyunsaturated and eight monounsaturated alkenes. The total quantity of CHCs differed among the populations with lady beetles from Tai’an (China) displaying a higher CHCs concentration than lady beetles from Gembloux (Belgium) and from Beijing (China) populations. Multivariate analyses detected differences in CHCs qualitative profiles, with females from Tai’an being different from the two other populations. Finally, our behavioural assays showed that females originating from the native Tai’an population were less preferred by males, while females from the invasive population were mounted more often. Our behavioural assays suggest that CHCs are not involved in discrimination of mating partners based on their origin. [less ▲]

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See detailCuticular hydrocarbon composition does not allow Harmonia axyridis males to identify the mating status of sexual partners
Legrand, Pauline ULiege; Vanderplanck, Maryse ULiege; Lorge, Stéphanie ULiege et al

in Entomologia Generalis (2019), 38(3), 211-224

Males of polyandrous species have to overcome sperm competition. They should select their mate based on the reproductive status of the female to increase their own fitness. Because the sexual behavior of ... [more ▼]

Males of polyandrous species have to overcome sperm competition. They should select their mate based on the reproductive status of the female to increase their own fitness. Because the sexual behavior of lady beetles relies on semiochemicals, with cuticular hydrocarbons (CHCs) being used for mate recognition, we developed and tested two hypotheses. First, we hypothesized that the cuticular hydrocarbon profile qualitatively and quantitatively differs between virgin and mated Harmonia axyridis females, regardless of the color morph. Second, we hypothesized that males discriminate virgin and mated females, preferring copulating with virgin females, rather than previously mated ones, to avoid sperm competition and subsequently increase their fitness. CHCs were solvent-extracted before being quantified and identified by gas chromatography. We found no qualitative differences between mated and unmated females irrespective of the morph; however, quantitative differences were detected. Specifically, the CHC profiles of mated females presented higher concentrations of alkenes, including 9-pentacosene, 9-heptacosene, and 9-hentriacontene. During dual-choice behavioral assays, males equally copulated with virgin and mated females. Our results suggest that there is no CHC-based discrimination strategy in virgin males of H. axyridis between virgin and once-mated females. We discuss alternative strategies that might be used in this lady beetle species. [less ▲]

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See detailThree Methods to Assess Levels of Farmers’ Exposure to Pesticides in the Urban and Peri-urban Areas of Northern Benin
Lawson, Armel Joël; Akohou, Hermine; Lorge, Stéphanie ULiege et al

in Tunisian Journal of Plant Protection (2017), 12(1), 91-108

Small farmers in urban and peri-urban areas of Northern Benin use pesticides without respect of hygiene rules and any personal protective equipment (PPE). Based on observation of the local practices in ... [more ▼]

Small farmers in urban and peri-urban areas of Northern Benin use pesticides without respect of hygiene rules and any personal protective equipment (PPE). Based on observation of the local practices in Djougou, Gogounou and Parakou,field trials have been carried out under similar conditions to evaluate contamination and exposure levels of farmers, using three usual sampling methods (Visual Method, Patch Method and Whole Body Method). Both Visual and Patch Methods used dye and ghost ink as tracers. In the Whole Body trials, deltamethrin (PLAN D 25 EC) was used as insecticide treatment. Deposits were observed on the protective equipment and on the collectors. Tartrazine was determined by colorimetry and deltamethrin by gas chromatography with ECD detector (GC-ECD). The examination of protective equipment (Visual Method) showed that the whole body could be potentially exposed to pesticides. Hands were contaminated during the preparation and the loading of mixture up to sprayer rinsing. The Patch Method was not perfectly able to predict the contamination pattern on the farmers’ body. The Whole Body Method results appeared to be more variable and influenced by the skill of each operator compared to the Patch Method. The contamination levels observed were rather higher than the value estimated with a theoretical model (from 368 to 2867 mg of deltamethrin at the total/body). With PPE, the average exposure reached 3.25 mg/kg bw/day. Without PPE, the potential exposure was equal to 32.52 mg/kg bw/day. Both values far exceed the AOEL of deltamethrin (0.0075 mg/kg bw/day) indicating a high risk level for the operator. The theoretical used model (UK-POEM) was unable to predict the potential exposure outcomes measured in these trials. [less ▲]

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See detailImpact of climatic factors on the release of E-β-caryophyllene from alginate beads
Daems, Frédéric ULiege; Bera, François ULiege; Lorge, Stéphanie ULiege et al

in Biotechnologie, Agronomie, Société et Environnement (2016), 20(2),

Description of the subject. Alginate beads that release semiochemical compounds are interesting biological control devices used to attract the natural enemies of aphids in infested crops. Little ... [more ▼]

Description of the subject. Alginate beads that release semiochemical compounds are interesting biological control devices used to attract the natural enemies of aphids in infested crops. Little information, however, is available about the impact of climatic factors on the release of semiochemicals from this diffusive system. Objectives. The objective of this scoping study was to investigate the impact of temperature, relative humidity and wind speed, on the release of E-β-caryophyllene from alginate beads. Method. The impact of the three climatic factors on the release of E-β-caryophyllene from alginate beads was evaluated using a Box-Behnken experimental design and a laboratory scale volatile collection system. The influence of relative humidity on bead water content and size, with and without this semiochemical, was also investigated using a gravimetric method and an easy-to-use photographic device, respectively. Results. The results showed that an increase in temperature caused a significant increase in the E-β¬-caryophyllene release rate. Neither relative humidity nor airflow, however, had a significant effect on the release of this semiochemical when relative humidity and wind speed ranged from 33% to 75% and from 6.61 x10-4 m.s-1 to 2.05 x10-2 m.s-1, respectively. The isotherm curves obtained were characteristic of food products and biopolymer materials. The isotherm shapes were not modified by the incorporation of the semiochemical into alginate beads, and showed an important increase in water content when relative humidity values exceeded 85%. Fortunately, this water content increase did not affect bead size, which facilitates the calculation of E-β-caryophyllene release. Conclusion. The present study shows for the first time the impact of the three main climatic factors on the release of E-β-caryophyllene from alginate beads. It allows learning more about how these biological control devices operate in order to optimize future field trials. [less ▲]

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See detailDevelopment of semiochemical slow-release formulations as biological control devices
Heuskin, Stéphanie ULiege; Lorge, Stéphanie ULiege; Leroy, Pascal ULiege et al

Poster (2012, July)

Semiochemicals have been widely considered within various integrated pest management (IPM) strategies. In the present work, two sesquiterpenoids, E-β-farnesene and E-β-caryophyllene, were formulated for ... [more ▼]

Semiochemicals have been widely considered within various integrated pest management (IPM) strategies. In the present work, two sesquiterpenoids, E-β-farnesene and E-β-caryophyllene, were formulated for their related properties as aphid enemy attractants. E-β-farnesene, the alarm pheromone of many aphid species, was also identified as a kairomone of aphid predators (Episyrphus balteatus De Geer (Diptera: Syrphidae)) and parasitoids (Aphidius ervi Haliday (Hymenoptera: Braconidae)). E-β-caryophyllene was identified as a potential component of the aggregation pheromone of the Asian ladybird, Harmonia axyridis Pallas, another aphid predator. The two products were purified from essential oils of Matricaria chamomilla L. (Asteraceae) and Nepeta cataria L. (Lamiaceae) for E-β-farnesene and E-β-caryophyllene, respectively. Natural and biodegradable slow-release formulations were then investigated in order to deliver these molecules on crop fields for a long period of time as biological control devices. Due to their sensitivity to oxidation, both sesquiterpenes needed to be protected from degradation. For this purpose, alginate – hydrophilic matrix with low oxygen permeability – was used as polymer for the formulations: the main objective was to deliver semiochemical substances in the air in a controlled way. Consequently, a careful selection of alginates was realised. Formulated beads showed different structural and encapsulation properties depending on various formulation factors. Alginate formulations were characterized by texturometry and by confocal microscopy in order to observe the distribution of semiochemicals in alginate network. The last step of alginate bead characterisation consisted in studying release rate of semiochemicals in laboratory-controlled conditions by optimised trapping and validated Fast-GC procedures. Finally, the efficiency of formulations as aphid predator (Syrphidae) and parasitoid (A. ervi) attractants was demonstrated by field trapping and olfactometry experiments. [less ▲]

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See detailA Semiochemical Slow-release Formulation in a Biological Control Approach to Attract Hoverflies
Heuskin, Stéphanie ULiege; Lorge, Stéphanie ULiege; Leroy, Pascal ULiege et al

in Journal of Environment and Ecology (2012), 3(1), 72-85

E-β-Farnesene, the alarm pheromone of many aphid species, and E-β-caryophyllene are considered as two sesquiterpenes attractive for aphid predators, among which Syrphidae species. Both compounds were ... [more ▼]

E-β-Farnesene, the alarm pheromone of many aphid species, and E-β-caryophyllene are considered as two sesquiterpenes attractive for aphid predators, among which Syrphidae species. Both compounds were formulated in alginate gel beads as slow-release devices in a biological control approach against aphids. Semiochemical diffusion from beads was studied in the laboratory according to abiotic parameters. Efficiency of formulations as hoverfly attractant was demonstrated in field experiments from June to August 2009. The diffusion of semiochemicals from alginate bead formulations was principally limited by high values (>85%) of relative humidity in the air. Temperature also impacts the release of volatile compounds. In field experiments, these two abiotic factors were supposed to highly condition the trapping of hoverflies. These field trappings demonstrated the efficiency of both semiochemical formulations compared to control (formulation without semiochemical) to catch females of Syrphidae during three months. [less ▲]

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See detailDevelopment of natural semiochemical slow-release formulations as biological control devices
Heuskin, Stéphanie ULiege; Lorge, Stéphanie ULiege; Leroy, Pascal ULiege et al

in Ioannou, Efstathia; Roussis, Vassilios (Eds.) Trends in natural products research : a PSE young scientists' meeting, June 12-15, 2011, Kolymvari - Crete. Book of abstracts (2011, June 12)

Semiochemicals – informative molecules used in insect-insect or plant-insect interactions – have been widely considered within various integrated pest management (IPM) strategies. In the present work, two ... [more ▼]

Semiochemicals – informative molecules used in insect-insect or plant-insect interactions – have been widely considered within various integrated pest management (IPM) strategies. In the present work, two sesquiterpenoids, E-β-farnesene and E-β-caryophyllene, were formulated for their properties as aphid enemy attractants. E-β-farnesene, the alarm pheromone of many aphid species, was also identified as a kairomone by attracting aphid predators and parasitoids. E-β-caryophyllene was identified as a potential component of the aggregation pheromone of the Asian ladybird, Harmonia axyridis Pallas, another aphid predator. The two products were purified from essential oils of Matricaria chamomilla L. (Asteraceae) and Nepeta cataria L. (Lamiaceae), respectively. Natural and biodegradable formulations were then investigated in order to deliver these molecules on crop fields for a long period of time as biological control devices. Due to their sensitivity to oxidation, both sesquiterpenes needed to be protected from oxygen degradation. For this purpose, alginate – hydrophilic matrix with low oxygen permeability – was used as polymer for the formulations: the main objective was to deliver semiochemicals in the air in a controlled way. Consequently, a careful selection of alginates was realised. Formulated beads showed different structural and encapsulation properties depending on various formulation factors. Alginate formulations were characterised by texturometry and by confocal microscopy in order to observe the distribution of semiochemicals in alginate network. The last step of alginate bead characterisation consisted in studying release rate of semiochemicals in laboratory-controlled conditions by optimised volatile collection system and validated fast GC analytical procedures Finally, the efficiency of formulations as aphid predator (Syrphidae species) and parasitoid (Aphidius ervi) attractants was demonstrated by field trapping and olfactometry experiments. [less ▲]

Detailed reference viewed: 116 (22 ULiège)