References of "Lognay, Georges"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailDevelopment of a performant method for glucocapparin determination in Boscia senegalensis Lam ex. Poir. : A study of the variability
Gueye, Momar Talla; Seck, Dogo; Diallo, Abdoulaye et al

in American Journal of Analytical Chemistry (2013), 4

This study describes a glucocapparin determination method. Based on rapeseed determination of glucosinolate (GSL), the equation of the average straight regression line is Y = 100.42X − 0.03 (R2 = 0.9998 ... [more ▼]

This study describes a glucocapparin determination method. Based on rapeseed determination of glucosinolate (GSL), the equation of the average straight regression line is Y = 100.42X − 0.03 (R2 = 0.9998). Enzymatic hydrolysis of glucocapparin extracted from leaves and fruits of B. senegalensis, analyzed by SPME-GC-MS confirmed the presence of methylisothiocyanate as the main hydrolysis glucocapparin product. Monitoring glucocapparin contents in B. senegalensis leaves and fruits collected in 4 localities in Senegal showed differences between organs according localities and periods of harvest. Glucocapparin content was very high in dry season particularly in January and the lowest rates were recorded during the rainy period between August and November. [less ▲]

Detailed reference viewed: 80 (15 ULg)
Full Text
Peer Reviewed
See detailRelationships between carcass traits and offal components in local poultry populations (gallus gallus) of Benin
Tougan, P.U.; Dahouda, M.; Salifou, C.F.A. et al

in Journal of Applied Biosciences (2013), 69

Objectives : The current work was carried out to determine the relationships between live weight, carcass traits and the offal components traits in Holli, Fulani, Sahoue, North and Southe indigenous ... [more ▼]

Objectives : The current work was carried out to determine the relationships between live weight, carcass traits and the offal components traits in Holli, Fulani, Sahoue, North and Southe indigenous chicken ectoypes of Benin. [less ▲]

Detailed reference viewed: 27 (5 ULg)
Full Text
Peer Reviewed
See detailRelationships between technological and nutritional meat quality parameters in local poultry populations (Gallus gallus) of Benin
Tougan, P.U.; Dahouda, M.; Salifou, C.F.A. et al

in International Journal of Biological Chemistry (2013), 7(6), 2450-2467

The current work aims at determining relationships between technological and nutritional meat quality parameters in Holli, Fulani, Sahoue, North and South indigenous chicken ecotypes of Benin.

Detailed reference viewed: 20 (3 ULg)
Full Text
Peer Reviewed
See detailEffect of processing conditions on phenolic compounds and antioxidant properties of date syrup
Abbès, F.; Kchaou, W.; Blecker, Christophe ULg et al

in Industrial Crops & Products (2013), 44

Commercial hydrolytic enzymes (pectinase and cellulase) were investigated for their influence on phenolics and antioxidant activities of date syrup. Content of total phenolics, flavonoids and carotenoids ... [more ▼]

Commercial hydrolytic enzymes (pectinase and cellulase) were investigated for their influence on phenolics and antioxidant activities of date syrup. Content of total phenolics, flavonoids and carotenoids contents were determined spectrophotometrically. Polyphenols composition was examined using HPLC. Seven phenolic compounds (catechin, vanillic acid, caffeic acid, syringic acid, p-coumaric acid, ferulic acid and sinapic acid) were detected in all date syrup extracts. p-Coumaric acid was the major compound of all date syrup extracts, representing 49.223-63.397%. The antioxidant activity of date syrup was evaluated by various antioxidant assays, including total antioxidant, DPPH scavenging test, FRAP, hydrogen peroxide scavenging activity and metal chelating activity.Results showed that the date syrup prepared after extraction with pectinase and cellulase mixture gave the lowest phenolic and flavonoid contents. For same variety, date syrup prepared after extraction with pectinase and cellulase mixture gave the highest carotenoids amounts. The antioxidant activity, determined by several methods, was significantly affected by the extraction method as well as date varieties. In fact, the date syrup prepared after extraction with pectinase and cellulase mixture gave the lowest antioxidant activity. A good correlation between the antioxidant activity and total phenolic content and flavonoid was observed. The discovery of our research is very important to scientists as well as to the fruit-processing industry to produce juice and syrup with high antioxidant activity. © 2012 Elsevier B.V. [less ▲]

Detailed reference viewed: 83 (15 ULg)
Full Text
Peer Reviewed
See detailCola pierlotii R.Germ. : étude de la composition chimique de la graine
Lognay, Georges ULg; Wathelet, Bernard ULg; Maesen, Philippe ULg

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2013), 17(2), 309-311

This note reports the first analysis of the chemical composition of Cola pierlotii seed. It compares the recorded values with various literature data on Cola nitida and Cola acuminata that are the two ... [more ▼]

This note reports the first analysis of the chemical composition of Cola pierlotii seed. It compares the recorded values with various literature data on Cola nitida and Cola acuminata that are the two most used species or as agent flavor or as a precursor drugs. Cola pierlotii is characterized in particular by a high caffeine content up to 1.27%. [less ▲]

Detailed reference viewed: 30 (7 ULg)
Full Text
Peer Reviewed
See detailImportance nutritionnelle du manioc et perspectives pour l’alimentation de base au Sénégal (synthèse bibliographique)
Diallo, Younoussa; Gueye, Momar Talla; Sakho, Mama et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2013), 17(4), 634-643

Cassava is one of the main plants and starchy roots grown in the world. In 2008, the total yield of cassava in West Africa represented 29% of the world production. However, in many West African countries ... [more ▼]

Cassava is one of the main plants and starchy roots grown in the world. In 2008, the total yield of cassava in West Africa represented 29% of the world production. However, in many West African countries such as Senegal, cassava is not used as a staple food. In fact, the processing techniques used for cassava are poorly known. In addition, the chemical composition of local cassava varieties has not yet been determined, nor has their toxicity been assessed. In 2004, showing an aggressive agricultural policy and revived interest, the Senegalese government launched a major program for intensifying the production of cassava for food security purposes. Cassava is an important source of calories and can be an interesting option for imported rice and wheat. Although many food products made from cassava are well known in the region, their use in the Senegalese diet is rare. Nevertheless, these cassava products are found as delicacies in some restaurants, and are consumed by the Senegalese and many other Africans. The objective of the present study is to demonstrate the nutritional value and the dietary possibilities of using cassava as a staple food in Senegal. [less ▲]

Detailed reference viewed: 101 (5 ULg)
Full Text
Peer Reviewed
See detailCharacterization of volatile organic compounds emitted by Barley (Hordeum vulgare L.) roots and their attractiveness to wireworms
Gfeller, Aurélie; Laloux, Morgan; Barsics, Fanny ULg et al

in Journal of Chemical Ecology (2013), 39(8), 1129-1139

Root volatile organic compounds (VOCs), their chemistry and ecological functions have garnered less attention than aboveground emitted plant VOCs. We report here for the first time on the identification ... [more ▼]

Root volatile organic compounds (VOCs), their chemistry and ecological functions have garnered less attention than aboveground emitted plant VOCs. We report here for the first time on the identification of VOCs emitted by barley roots (Hordeum vulgare L.). Twenty nine VOCs were identified from isolated 21-d-old roots. The detection of root volatiles was dependent on the medium used for root cultivation. From 7-d-old roots cultivated on sterile Hoagland gelified medium, 24 VOCs were identified, on sterile vermiculite 33 VOCs, and on non-sterile vermiculite 34 VOCs. The major VOCs identified were fatty acid derived compounds, including hexanal, methyl hexanoate, (E)-hex-2-enal, 2-pentylfuran, pentan-1-ol, (Z)-2-(pentenyl)-furan, (Z)-pent-2-en-1-ol, hexan-1-ol, (Z)-hex-3-en-1-ol, (E)-hex-2-en-1-ol, oct-1-en-3-ol, 2-ethylhexan-1-ol (likely a contaminant), (E)-non-2-enal, octan-1-ol, (2E,6Z)-nona-2,6-dienal), methyl (E)-non-2-enoate, nonan-1-ol, (Z)-non-3-en-1-ol, (E)-non-2-en-1-ol, nona-3,6-dien-1-ol and nona-2,6-dien-1-ol. In an olfactometer assay, wireworms (larvae of Agriotes sordidus Illiger, Coleoptera: Elateridae) were attracted to chemical cues emanating from barley seedlings. We discuss the role of individual root volatiles or a blend of the root volatiles detected here and their interaction with CO2for wireworm attraction. [less ▲]

Detailed reference viewed: 131 (37 ULg)
Full Text
Peer Reviewed
See detailEffects of fruit maturity on oxidative stability of Lagenaria siceraria (Molina) standl. seed oil extracted with hexane
Loukou, A.L.; Lognay, Georges ULg; Baudoin, Jean-Pierre ULg et al

in Journal of Food Biochemistry (2013), 37(4), 475-484

Detailed reference viewed: 27 (5 ULg)
Full Text
Peer Reviewed
See detailImprovement of Ylang-Ylang Essential Oil Characterization by GCxGC-TOFMS
Brokl, Michal ULg; Fauconnier, Marie-Laure ULg; Benini, Céline et al

in Molecules (2013), 18(2), 1783-1797

A single fraction of essential oil can often contain hundreds of compounds. Despite of the technical improvements and the enhanced selectivity currently offered by the state-of-the-art gas chromatography ... [more ▼]

A single fraction of essential oil can often contain hundreds of compounds. Despite of the technical improvements and the enhanced selectivity currently offered by the state-of-the-art gas chromatography (GC) and mass spectrometry (MS) instruments, the complexity of essential oils is frequently underestimated. Comprehensive two-dimensional GC coupled to time-of-flight MS (GC×GC-TOFMS) was used to improve the chemical characterization of ylang-ylang essential oil fractions recently reported in a previous one-dimensional (1D) GC study. Based on both, the enhanced chromatographic separation and the mass spectral deconvolution, 161 individual compounds were identified and labeled as potentially characteristic analytes found in both low and high boiling fractions issued from distillation of mature ylang-ylang flowers. Compared to the most recent full GC-MS characterization, this represents 75 new compounds, essentially consisting of terpenes, terpenoid esters, and alcohols. [less ▲]

Detailed reference viewed: 64 (17 ULg)
Full Text
Peer Reviewed
See detailAggregation behaviour of Harmonia axyridis
Durieux, Delphine ULg; Fischer, Christophe ULg; Fassotte, Bérénice ULg et al

in Bulletin OILB/SROP = IOBC/WPRS Bulletin (2013), 94

The multicoloured Asian ladybeetle, Harmonia axyridis (Coleoptera: Coccinellidae), forms large aggregations inside dwellings to survive cold winters. The species’ migratory flight is well documented ... [more ▼]

The multicoloured Asian ladybeetle, Harmonia axyridis (Coleoptera: Coccinellidae), forms large aggregations inside dwellings to survive cold winters. The species’ migratory flight is well documented. Harmonia axyridis preferentially moves towards prominent and visually contrasting elements (Obata, 1986; Nalepa et al., 2005). However, the mechanisms involved in the selection of aggregation sites are misunderstood. The work presented here was devoted to the study of chemicals used by H. axyridis during its aggregation process. During sampling of infested dwellings, non-volatile compounds were collected from aggregation sites. Gas chromatrography-mass spectometry (GC-MS) analyses showed that the chemicals found on the substrate where the beetles aggregate were different from the ones collected around these aggregation sites. These two blends are made up of the same long-chain hydrocarbons, comprising saturated and unsaturated homologues, but they are quantitatively different, the blend collected directly on the overwintering sites containing a higher proportion of saturated compounds than the other one. Behavioural experiments, involving overwintering H. axyridis individuals, were then conducted in the laboratory to understand the roles of these chemicals in aggregation. Firstly, an aggregation assay using the blend collected inside overwintering sites showed a clear preference of ladybeetles for areas containing these compounds, highlighting the retention capacity of the blend on H. axyridis. On the other hand, a Y-shaped tube assay, using the chemical blend found around the sites, showed that those compounds are used by male and female congeners as cues, allowing individuals to orientate towards the side of the set-up containing the tested chemicals. These results suggest the use of two different area markings by H. axyridis during its aggregation: the first one to lead congeners towards aggregation sites, and the second to ensure the cohesion of the cluster. Additional investigations were conducted to study the influence of (1) the presence of congeners and (2) the shelters’ luminosity on the H. axyridis decision to settle and aggregate under shelters. A binary choice experiment conducted in the laboratory under non-wintering conditions showed that the multicoloured Asian ladybeetles present a permanent aggregative behaviour, as a result of the existence of social interactions. These experiments also highlighted the clear preference of H. axyridis for dark shelters. [less ▲]

Detailed reference viewed: 80 (16 ULg)
Full Text
See detailLes ressources sauvages comestibles des bois de tapias : caractérisation alimentaire des produits consommés
Barsics, Fanny ULg; Malaisse, François ULg; Lognay, Georges ULg et al

in Verheggen, François; Bogaert, Jan; Haubruge, Eric (Eds.) Les vers à soie malgaches. Enjeux écologiques et socio-économiques. (2013)

Les bois de tapia (Uapaca bojeri) des Hautes Terres centrales de Madagascar regorgent de ressources sauvages comestibles utilisées par les populations locales dans leur alimentation régulière. Afin de ... [more ▼]

Les bois de tapia (Uapaca bojeri) des Hautes Terres centrales de Madagascar regorgent de ressources sauvages comestibles utilisées par les populations locales dans leur alimentation régulière. Afin de décrire ces apports en termes biochimiques, nous avons réalisé des analyses de contenu sur 7 ressources, soit 2 chenilles, 1 araignée et 4 champignons comestibles. Leurs taux de protéines, de lipides, ainsi que leur composition en acides aminés et acides gras ont été obtenus. Les résultats ont été exprimés dans l’absolu mais aussi en relation avec les indices alimentaires couramment utilisés pour définir les qualités protéiques et lipidiques des denrées. Ces analyses nous permettent de constater l’excellent apport protéique que représentent les Arthropodes, et mettent également en évidence leur qualité lipidique. Les résultats de ces analyses sont discutés en faisant le lien avec les recommandations de la FAO/OMS. [less ▲]

Detailed reference viewed: 78 (15 ULg)
Full Text
Peer Reviewed
See detailThe relevance of food composition data for nutrition surveys in rural Tibet: pilot study in the context of Kashin-Beck Disease
DERMIENCE, Michael ULg; Mathieu, Françoise; Barthelemy, Jean-Paul ULg et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2013), 17(1), 32-42

Kashin-Beck disease (KBD) is an endemic and chronic osteochondropathy. This disease principally occurs in the Tibet Autonomous Region and in several provinces of the People’s Republic of China. The ... [more ▼]

Kashin-Beck disease (KBD) is an endemic and chronic osteochondropathy. This disease principally occurs in the Tibet Autonomous Region and in several provinces of the People’s Republic of China. The etiology of the disease remains obscure although environmental factors are assumed to be involved. Diet, in particular, differentiates the rural community, affected by KBD, from the other communities (nomads and city-dwellers), who remain unaffected. In anticipation of a nutrition survey, this study aimed to measure the mineral content (Ca, P, Mg, Fe, Zn, Mn, Cu, Ni, Se, Al, Sr, Mo, Cd, As, Pb, Hg, Cr, and Co) of eight Tibetan staple foods and to compare the results against two food composition tables (FCTs). Foods were sampled in twenty households selected from both an endemic and a non-endemic area of rural Tibet. Ten minerals involved in bone metabolism were measured using atomic and molecular spectrometric methods. Results revealed that a very limited number of food/constituent pairs showed a variation in mineral composition during a single year of testing for a given region. In addition, results showed significant differences in mineral content between the endemic and the non-endemic area, especially for wheat flour. Following our analysis of the mineral content of the Tibetan food samples, results were statistically compared with similar foods listed in two food composition tables: the USDA National Nutrient Database (USDA Food Search for Windows, Version 1.0, database version SR23), and the China Food Composition Table (book 1, 2nd edition). More than 50 to 60% of p-values < 0.05 were highlighted, suggesting the inappropriateness of using FCTs as a reference for nutrition surveys in rural Tibet, and emphasizing the need for analysis of traditional foods. Differences were found to be more or less marked depending on the element considered, and calcium content seemed to show the greatest difference. Although it is obviously too early for definite conclusions to be reached (insufficient number of samples by food and insufficient number of foods analyzed), it seems that the present pilot-study indicates significant discrepancies between measured and tabulated values of the mineral content of certain foods. A more complete survey would therefore seem mandatory. [less ▲]

Detailed reference viewed: 115 (21 ULg)
Full Text
Peer Reviewed
See detailSimple and Automatic Closed Grinding and Extraction System
Fischer, Christophe ULg; Lognay, Georges ULg

in Journal of Chemical Education (2012)

This article describes a simple, automatic, and closed grinding system for small samples using common laboratory equipment that is particularly useful for air-sensitive samples or volatile compounds ... [more ▼]

This article describes a simple, automatic, and closed grinding system for small samples using common laboratory equipment that is particularly useful for air-sensitive samples or volatile compounds analyses. [less ▲]

Detailed reference viewed: 146 (31 ULg)
Full Text
Peer Reviewed
See detailChoosing an aphid partner: a matter of taste and smell
Detrain, Claire; Fischer, Christophe ULg; Lognay, Georges ULg et al

Conference (2012, August 27)

Honeydew is the keystone upon which ants and aphids build their mutualistic relationship. We have investigated how sugar and volatile compounds from honeydew are involved in the discovery, the recognition ... [more ▼]

Honeydew is the keystone upon which ants and aphids build their mutualistic relationship. We have investigated how sugar and volatile compounds from honeydew are involved in the discovery, the recognition and the exploitation of aphid colonies by the black garden ant Lasius niger. In addition to semiochemicals produced by aphids, honeydew volatile compounds are used by ant scouts to orient themselves and distantly recognize myrmecophilous species. Once discovered, aphid colonies producing sugars which are the most beneficial to the ants are preferentially tended. In this respect, the ways each sugar acts upon the feeding behavior of ant foragers and triggers the laying of a recruitment trail are essential to understand how their collective exploitation of aphid colonies proceeds and why mutualistic interactions between ants and aphids are maintained. Sensitivity of ant scouts to honeydew sugars was also investigated. Dose-response curves revealed between-sugar differences with foragers being very sensitive even to small amounts of melezitose, a sugar specifically produced by aphid colonies. We discuss about the relevance of honeydew cues used by ants in the selection of sugary resources, the recognition of their honeydew-producing partners as well as in the assessment of size and nutritive value of exploited aphid colonies. [less ▲]

Detailed reference viewed: 70 (9 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 131 (32 ULg)
Full Text
Peer Reviewed
See detailBehavioral response of Harmonia axyridis towards their footprints according to their physiological state
Durieux, Delphine ULg; Fassotte, Bérénice ULg; Vanderplanck, Maryse et al

Poster (2012, August)

In order to survive cold, the multicolored Asian ladybeetle, Harmonia axyridis (Pallas), aggregates inside dwellings during winter. It has been recently highlighted that overwintering H. axyridis ... [more ▼]

In order to survive cold, the multicolored Asian ladybeetle, Harmonia axyridis (Pallas), aggregates inside dwellings during winter. It has been recently highlighted that overwintering H. axyridis individuals lay an area marking while walking, which is used by conspecifics to locate aggregation sites. These footprints are made-up of hydrocarbons, comprising both saturated and unsaturated homologues. However, it has not been demonstrated whether this “following area marking” behavior is specific to the overwintering individuals. The work presented herein was oriented to the study of the chemical evolution of these footprints according to the physiological state of H. axyridis. Monthly GC-MS analyses revealed that the area marking contained a greater amount of di-unsaturated compounds when laid by overwintering ladybeetles, suggesting the great importance of these chemicals in the ladybeetles aggregation process. In the second instance, behavioral investigations conducted in a Y-shaped glass tube were performed to assess (1) the evolution of H. axyridis behavior towards their footprints and (2) whether this behavioral modification is due to an evolution of the ladybeetles sensitivity or rather to an evolution of the area marking attractiveness. The results revealed that only the overwintering individuals follow their area marking, and that this behavior is linked to the ladybeetle physiological state rather than to the chemical profile of the marking biomolecules. [less ▲]

Detailed reference viewed: 78 (18 ULg)
Full Text
See detailImpact of Myzus persicae infestation on the volatile emission of Arabidopsis thaliana Col-0.
Hien, Truong Thi Dieu ULg; Delaplace, Pierre ULg; Francis, Frédéric ULg et al

Poster (2012, July 22)

Being members of complex communities, plants often emit a wide range of volatile organic compounds to defend themselves against insect invasions. Although many studies exist on insect-induced plant ... [more ▼]

Being members of complex communities, plants often emit a wide range of volatile organic compounds to defend themselves against insect invasions. Although many studies exist on insect-induced plant volatile emission, most of them either compare the influences of various herbivore species on one plant species or the impact of a given herbivore on several host plant species. Moreover, informations related to the influence of insect density as well as the infestation duration are still needed. Here, we showed that a sucking insect – Myzus persicae (green peach aphid) induced the volatile emission from Arabidopsis thaliana Columbia wild-type (A.thaliana Col-0) under laboratory conditions based on results obtained by solid-phase micro-extraction coupled with gas chromatography - mass spectrometry (SPME-GC/MS). The released volatile blend was discussed in relation to related biosynthesis pathways and functions. These included terpenoids, green leaf volatiles, alcohols and isothiocyanate. The qualitative and overall proportion of volatile components differed depended on the number and residence duration of aphids on leaves. By studying the effects of sucking insect stresses to plant, we not only aim to contribute to the fundamental understanding of the emission of volatile components in the interaction between plants and pests, but also to provide standardised and easy to use assays to assess A.thaliana volatile changes according to cross stresses, including both biotic and abiotic ones in ongoing experiments. [less ▲]

Detailed reference viewed: 100 (21 ULg)
Full Text
Peer Reviewed
See detailModeling of the Diffusion of VOCs Emitted by Barley Roots
Hirtt, Laura ULg; Destain, Marie-France ULg; Lognay, Georges ULg et al

Poster (2012, July 02)

Detailed reference viewed: 52 (21 ULg)
Full Text
Peer Reviewed
See detailFlexible aggregative behavior of Harmonia axyridis according to the freshness of area marking in overwintering sites
Durieux, Delphine ULg; Fischer, Christophe ULg; Fassotte, Bérénice ULg et al

Poster (2012, July)

The multicolored Asian ladybeetle, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), aggregates inside dwellings and buildings during winter to survive cold. This adaptive behavior causes annoyances ... [more ▼]

The multicolored Asian ladybeetle, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), aggregates inside dwellings and buildings during winter to survive cold. This adaptive behavior causes annoyances to the occupants because of their large number and the induction of allergic reactions. Although this species has aroused a great interest these last years, the factors involved in the selection of its overwintering sites remain misunderstood. The work presented herein was oriented to the study of the non-volatile chemical compounds involved in this aggregation behavior. Chemical analyses revealed the occurrence, in aggregation sites, of an area marking made up of saturated and unsaturated hydrocarbons. Behavioral investigations demonstrated that H. axyridis preferentially aggregates in sites previously marked by congeners, indicating the retention potential of this blend on overwintering individuals. In the second instance, the same analyses were performed on an area marking aged of one year. The chemical investigations showed that only saturated hydrocarbons can still be detected after that period of time but the remaining blend does not induce aggregation anymore. This difference of response according to the freshness of the area marking suggests that this species would not be prisoner of the marking previously deposited on the substrate if the surrounding has changed and the site is not suitable anymore. [less ▲]

Detailed reference viewed: 34 (10 ULg)