References of "Heuskin, Stéphanie"
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See detailDoes the facultative bacteria Serratia symbiotica influence the foraging strategies of aphid parasitoids?
Attia, Sabrine; Louâpre, Philippe; Foray, Vincent et al

Poster (2014)

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See detailLa validation de méthodes d'analyse
Heuskin, Stéphanie ULg

Scientific conference (2013, December)

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See detailL'étude des sémiochimiques. Applications en écologie chimique
Heuskin, Stéphanie ULg

Scientific conference (2013, November 21)

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See detailFumigant toxicity of Mentha pulegium and Citrus aurantium essential oils to Tetranychus urticae (Acari: Tetranychidae) and Phytoseiulus persimilis (Acari: Phytoseiidae)
Attia, Sabrine; Grissa, K.L.; Lognay, Georges ULg et al

in Boeckx; Bossier, Peter; Smagghe, Guy (Eds.) et al Proceedings of the 65th international symposium on crop protection (2013, May 21)

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See detailDéveloppements analytiques appliqués à une thématique d'écologie chimique
Heuskin, Stéphanie ULg

Scientific conference (2013, February)

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See detailThe scent of inbreeding: a male sex pheromone betrays inbred males
Van Bergen, E.; Brakefield, P.; Heuskin, Stéphanie ULg et al

Poster (2013)

Inbreeding depression results from mating among genetically related individuals and impairs reproductive success. The decrease in male mating success is usually attributed to an impact on multiple fitness ... [more ▼]

Inbreeding depression results from mating among genetically related individuals and impairs reproductive success. The decrease in male mating success is usually attributed to an impact on multiple fitness-related traits that reduce the general condition of inbred males. However, the reduced mating success of inbred males could also be a consequence of strong selection on females to avoid mating with an inbred male. This is especially relevant if females gain direct benefits through appropriate mate choice (parental care, territory defences, nuptial gifts) or if they suffer direct costs should they mate with an inbred male (decreased offspring viability and fertility). Here we find that the production of the male sex pheromone is reduced significantly by inbreeding in the butterfly Bicyclus anynana. Other traits indicative of the general condition, including flight performance, are also negatively affected in male butterflies by inbreeding. Yet we unambiguously show that only the production of male pheromones affects mating success. Thus, this pheromone signal informs females about the inbreeding status of their mating partners. We also identify the specific chemical component, hexadecanal, likely responsible for the decrease in male mating success. Our results advocate giving increased attention to olfactory communication as a major causal factor of mate-choice decisions and sexual selection. [less ▲]

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See detailThe scent of inbreeding: male sex pheromones betray inbred males
Nieberding, C.; Van Bergen, E.; Brakefield, P. et al

in Chem. Senses (2013)

Inbreeding depression results from mating among genetically related individualsand impairs reproductive success. The decrease in male matingsuccess is usually attributed to an impact on multiple fitness ... [more ▼]

Inbreeding depression results from mating among genetically related individualsand impairs reproductive success. The decrease in male matingsuccess is usually attributed to an impact on multiple fitness-related traitsthat reduce the general condition of inbred males. Here, we find that the productionof the male sex pheromone is reduced significantly by inbreeding inthe butterfly Bicyclus anynana. Other traits indicative of the general condition,including flight performance, are also negatively affected in malebutterflies by inbreeding. Yet, we unambiguously show that only the productionof male pheromones affects mating success. Thus, this pheromonesignal informs females about the inbreeding status of their mating partners.We also identify the specific chemical component, hexadecanal, probablyresponsible for the decrease in male mating success. Our results advocategiving increased attention to olfactory communication as a major causalfactor of mate-choice decisions and sexual selection.Published in the Proceedings of the Royal Society of London (2013) in press. [less ▲]

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See detailDissecting the mechanisms underlying old male mating advantage in a butterfly
Karl, Isabell; Heuskin, Stéphanie ULg; Fischer, Klaus

in Behavioral Ecology and Sociobiology (2013)

Selection is expected to maximize an individual’s own genetic reward regardless of the potential fitness consequences for its sexual partners, which may cause sexual conflict. Although performance in ... [more ▼]

Selection is expected to maximize an individual’s own genetic reward regardless of the potential fitness consequences for its sexual partners, which may cause sexual conflict. Although performance in holometabolous insects typically diminishes with age, old male mating advantage has been documented in a few species. Whether this pattern arises from female preference for older males based on, e.g., pheromone blends (intersexual selection), or from increased eagerness to mate in older compared to younger males is currently debated. We explore the mechanistic basis of old male mating advantage, using a series of experiments including behavioral as well as manipulative approaches, in the tropical butterfly Bicyclus anynana. Consistent with the residual reproductive value hypothesis, old male mating advantage was associated with a greater eagerness to mate, evidenced by a two times higher flying and courting activity in older than in younger males. In contrast, we found only limited support for a contribution of female preference for older males based on pheromone composition, although male sex pheromones clearly do play a role in mating success. Our results suggest that male behavior may play a primary role in old male mating advantage, and that pheromones are likely of secondary importance only. Male mating success was related to higher overall pheromone titers rather than variation in a single component. A dominant importance of male behavior in determining mating success may result in sexual conflict. [less ▲]

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See detailThe scent of inbreeding: male sex pheromones betray inbred males
van Bergen, Erik; Brakefield, Paul M.; Heuskin, Stéphanie ULg et al

in Proceedings of the Royal Society B : Biological Sciences (2013)

Inbreeding depression results from mating among genetically related individuals and impairs reproductive success. The decrease in male mating success is usually attributed to an impact on multiple fitness ... [more ▼]

Inbreeding depression results from mating among genetically related individuals and impairs reproductive success. The decrease in male mating success is usually attributed to an impact on multiple fitness-related traits that reduce the general condition of inbred males. Here, we find that the production of the male sex pheromone is reduced significantly by inbreeding in the butterfly Bicyclus anynana. Other traits indicative of the general condition, including flight performance, are also negatively affected in male butterflies by inbreeding. Yet, we unambiguously show that only the production of male pheromones affects mating success. Thus, this pheromone signal informs females about the inbreeding status of their mating partners. We also identify the specific chemical component, hexadecanal, probably responsible for the decrease in male mating success. Our results advocate giving increased attention to olfactory communication as a major causal factor of mate-choice decisions and sexual selection. [less ▲]

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See detailAnalysis of the diastereoisomers of alliin by HPLC
DETHIER, Bérénice ULg; Laloux, Morgan ULg; Hanon, Emilien et al

in Talanta (2012), 101

Garlic has been known for its therapeutic effects for centuries and is used worldwide as a functional food. The concentration of the active molecules could be enhanced by a better knowledge of their ... [more ▼]

Garlic has been known for its therapeutic effects for centuries and is used worldwide as a functional food. The concentration of the active molecules could be enhanced by a better knowledge of their biosynthesis. The precursor of these compounds, alliin (a sulfur amino-acid) has been obtained by chemical synthesis. However, this synthesis route also leads to a diastereoisomer as co-product. This work describes the development of an analytical method which allows the separation and quantification of the two diastereoisomers in order to determine in which proportion the natural form can be produced. The HPLC method which was optimized and validated by accuracy profile exploits an original stationary phase consisting of porous graphitic carbon (PGC). Furthermore, the developped method was used to separate the diastereoisomers of methiin, another garlic cysteine sulfoxide, and to analyse and aqueous extract of garlic. The ability to quantify the amount of natural alliin is valuable for further work on garlic molecules and their application for health protection. [less ▲]

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See detailHoneydew volatile emission acts as a kairomonal message for the Asian lady beetle Harmonia axyridis (Coleoptera: Coccinellidae)
Leroy, Pascal; Heuskin, Stéphanie ULg; Sabri, Ahmed ULg et al

in Insect Science (2012), 19(4), 498-506

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 attractant for many aphid predators ... [more ▼]

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 attractant 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-1-butanol and 3-methyl-butanal were highlighted as the two most abundant semiochemicals released from the M. viciae honeydew. Vicia 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. Limonenewas the most efficient attractant since 89% of the H. axyridis responded to this odor. The use of the identified semiochemicals aswell as the composition of an artificial honeydew could certainly be helpful to control the dispersal of the Asian lady beetle H. axyridis. [less ▲]

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See detailDevelopment of semiochemical slow-release formulations as biological control devices
Heuskin, Stéphanie ULg; Lorge, Stéphanie ULg; Leroy, Pascal ULg 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 detailExpanding on olfactory communication in a butterfly: cuticular chemicals indicate sex and age in Bicyclus anynana
Heuskin, Stéphanie ULg; Kaltenpoth, M.; Engl, T. et al

in International Society of Chemical Ecology, 28th Annual Meeting. Abstracts (2012, July)

Chemical (olfactory or gustatory) communication is fundamental to most living organisms but widely understudied compared to other channels of communication such as vision and audition, principally in ... [more ▼]

Chemical (olfactory or gustatory) communication is fundamental to most living organisms but widely understudied compared to other channels of communication such as vision and audition, principally in sexual selection . Here we present the first extensive analysis of cuticular chemical diversity in a butterfly, and investigate whether molecules inform potential mating partners about sex and age. Bicyclus anynana was chosen for its well-known potentialities as a lab model in eco-evo-devo studies , . Chemical interactions have been investigated so far in this species with focus on volatile olfactory components: male sexual pheromones composition and their roles in sexual selection , , their change in ratio with male age, inbreeding coefficient, and other factors . Here we aim completing the picture fully and focus on gustatory non-volatile cuticular chemical diversity in this model species. Indeed, as for Drosophila, the courtship of this butterfly is composed of a series of steps that include short-range interactions during which various chemicals may be involved in mate-choice, through olfactory but also gustatory channels of communication (Nieberding et al., data not published). More than hundred cuticular chemicals were identified and quantified by GC-MS analyses on different parts (abdomen, antennae, head, legs and wings) of B. anynana individuals (n=42, 210 GC-MS analyses) of each sex and at different ages (from 1 to 21 days old). The analysis of the chemical distribution was realised by multivariate statistical analyses (perMANOVA). The results led to the conclusion that some cuticular chemicals are indicative for the body parts and can inform about sex and age. [less ▲]

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See detailA Semiochemical Slow-release Formulation in a Biological Control Approach to Attract Hoverflies
Heuskin, Stéphanie ULg; Lorge, Stéphanie ULg; Leroy, Pascal ULg 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 detailUtilisation d'une composition comme attractant d'auxiliaires
Leroy, Pascal; Sabri, Ahmed; Heuskin, Stéphanie ULg et al

Patent (2012)

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See detailA new HPLC method to quantify alliin, the major sulfur compound in garlic
DETHIER, Bérénice ULg; Laloux, Morgan ULg; Hanon, Emilien et al

Poster (2012, February 10)

Garlic is recognized for centuries for its health benefits, mostly linked to its sulfur- components. Among the products extracted from the cloves, alliin retained our attention. Alliin was synthesized ... [more ▼]

Garlic is recognized for centuries for its health benefits, mostly linked to its sulfur- components. Among the products extracted from the cloves, alliin retained our attention. Alliin was synthesized. This process leads to two stereoisomers. Their HPLC separation was the aim of this work. The method described in the literature (amino column, detection at 210 nm) showed a resolution of 1,1 between the isomers. A second method was developed: the stationary phase was porous graphitic carbon and a water-ACN gradient was used for the elution. It provided a resolution of 3,2, was shorter and underwent the validation process. The method leads to satisfying results. The separation is excellent, and the validation criteria are fulfilled. This may be valuable for future research on garlic. [less ▲]

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See detailDéveloppements analytiques appliqués à une thématique d'écologie chimique
Heuskin, Stéphanie ULg

Scientific conference (2012, February)

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See detailMicroorganisms from aphid honeydew attract natural enemies and tending ants
Verheggen, François ULg; Leroy, Pascal; Fischer, Christophe ULg et al

Conference (2012, February)

Aphids are some of the most serious pests of cultivated crops worldwide, causing major yield and economic losses. Previous works have demonstrated ants and natural enemies (including ladybeetles and ... [more ▼]

Aphids are some of the most serious pests of cultivated crops worldwide, causing major yield and economic losses. Previous works have demonstrated ants and natural enemies (including ladybeetles and hoverflies) to be able to use aphid volatile chemicals to locate aphid colonies. Here, we report the first isolation of a bacterium from the pea aphid Acyrthosiphon pisum honeydew, Staphylococcus sciuri, which produces kairomones used by the aphidophagous hoverfly Episyrphus balteatus and the Asian Ladybeetle Harmonia axyridis during their search for prey colonies. Some specific semiochemicals produced by S. sciuri were identified as attractants and ovipositional stimulants. Similarly, we have shown scouts of the aphid tending ant species, Lasius niger, to orientate their foraging behaviour toward an Aphis fabae infested plant and we have demonstrated that the odours released by this aphid honeydew were attractive for ant scouts. Again, bacteria were involved in the production of these honeydew semiochemicals. Interestingly, ant scouts were also able to discriminate honeydew odour from A. fabae (usually attended by L. niger) and A. pisum (unattendedby L. niger). Comparison of the volatile and bacteria composition of both aphid species honeydew were attended. [less ▲]

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