References of "Verheggen, François"
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See detailThe scent of love: how important are semiochemicals in the sexual behavior of lady beetles?
Fassotte, Bérénice ULg; Francis, Frédéric ULg; Verheggen, François ULg

in Journal of Pest Science (in press)

Chemical signals are involved in the courtship behavior of many invertebrate and vertebrate species. Lady beetles are no exception to this rule; a significant number of published reports highlight the ... [more ▼]

Chemical signals are involved in the courtship behavior of many invertebrate and vertebrate species. Lady beetles are no exception to this rule; a significant number of published reports highlight the role of cuticular chemicals involved in the reproduction of lady beetles, including gender recognition. Recent data have also demonstrated the presence of a volatile female sex pheromone that facilitates male attraction in some species. Here, we present a synthetic overview of the current knowledge about the sexual behavior of lady beetles and associated chemicals for which the function and identification have been provided. Because lady beetles are often reared as biological control agents, the chemical cues involved in their sexual behavior could be used as components in integrated management approaches against soft-bodied hemipterans. In conclusion, this review provides new perspectives and potential developments for sustainable insect management mainly based on the semiochemicals involved in the sexual behavior of lady beetles. A better understanding of these chemical signals would help maximize their presence in areas where their predatory behavior is requested, as a result of the application of formulations inducing behavioral manipulation. [less ▲]

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See detailReview: Implementing biostimulants and biocontrol strategies in the agroecological management of cultivated ecosystems
Le Mire, Géraldine ULg; Nguyen, Minh ULg; Fassotte, Bérénice ULg et al

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

This review describes the current methods for exploiting and applying plant growth-promoting rhizbacteria (PGPR), elicitors and semiochemical products in contemporary agricultural systems. The future of ... [more ▼]

This review describes the current methods for exploiting and applying plant growth-promoting rhizbacteria (PGPR), elicitors and semiochemical products in contemporary agricultural systems. The future of these biostimulant and biocontrol tools for the sustainable management of agricultural practices is also discussed. Special attention is given to the formulation of these products and the network of interactions taking place in cultivated ecosystems [less ▲]

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See detailBACTERIA MAY CONTRIBUTE TO DISTANT SPECIES RECOGNITION IN ANT-APHID MUTUALISTIC RELATIONSHIPS
Fischer, Christophe ULg; Detrain, Claire; Thonart, Philippe ULg et al

in Insect Science (in press)

Mutualistic interactions between ant and aphid species have been the subject of considerable historical and contemporary investigations, the primary benefits being cleaning and protection for the aphids ... [more ▼]

Mutualistic interactions between ant and aphid species have been the subject of considerable historical and contemporary investigations, the primary benefits being cleaning and protection for the aphids and carbohydrate-rich honeydew for the ants. Questions remained, however, as to the volatile semiochemical factor influencing this relationship. A recent study highlighted the role of bacterial honeydew volatile compounds in ant attraction. Here, ant’s ability to distantly discriminate two aphid species was investigated based on bacterial honeydew semiochemicals emissions using a two-way olfactometer. Both the mutualistic black bean aphid (Aphis fabae L.) and the non-myrmecophilous pea aphid (Acyrthosiphon pisum Harris) were found to be attractive for the black garden ant (Lasius niger L.). The level of attraction was similar in both assays (control versus one of the aphid species). However, when given a choice between these two aphid species, ants showed a significant preference for Aphis fabae. Honeydew volatiles, mostly from bacterial origins, are known to be a key element in ant attraction. Using the same olfactometry protocol, the relative attractiveness of volatiles emitted by honeydews collected from each aphid species and by bacteria isolated from each honeydew was in investigated. Again, ants significantly preferred volatiles released by Aphis fabae honeydew and bacteria. This information suggests that microbial honeydew volatiles enable ants to distantly discriminate aphid species. These results emphasize the importance of investigating the presence and potential effects of microbes in insect symbioses. [less ▲]

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See detailAbility of Tuta absoluta (Lepidoptera: Gelechiidae) to develop on alternative host plant species
Bawin, Thomas ULg; Dujeu, David; De Backer, Lara ULg et al

in Canadian Entomologist (2015)

The tomato leafminer, Tuta absoluta Meyrick (Lepidoptera: Gelechiidae), is a widespread devastating pest reported to develop on economically important solanaceous crops. The characterization of its host ... [more ▼]

The tomato leafminer, Tuta absoluta Meyrick (Lepidoptera: Gelechiidae), is a widespread devastating pest reported to develop on economically important solanaceous crops. The characterization of its host range could help to understand and prevent the dispersion behavior of the insect in the environment. In this study, the ability of T. absoluta to develop on 12 cultivated or non-cultivated plants including Solanaceae, Chenopodiaceae, Convolvulaceae, Fabaceae and Malvaceae species under laboratory conditions was assessed. For each plant species, we monitored the development times of immature stages, survival, sex ratios and adult fecundity rates. All the 6 tested non-solanaceous plants, including Chenopodium, Convolvulus and Malva species, were not able to sustain (i.e. allow growth and development) T. absoluta larvae. Among Solanaceae, Solanum species were the most suitable host plants for the pest, but others could be opportunistically colonized with fewer incidences. T. absoluta appears to be strongly related to solanaceous plants which would predominantly support self-sustaining field populations. Preventing crop infestation by removing potential host plants in the immediate field vicinity and culture rotations with non-solanaceous crops is of primary importance. [less ▲]

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See detailDo changes in atmospheric CO2 concentration affect aphid alarm signaling?
Boullis, Antoine ULg; Appeldoorn, Claire; Oostrom, Marjolein et al

Conference (2015, November 06)

The effects of global atmospheric changes on vegetation and associated insect populations are increasingly studied, but how these gases affect the interactions between herbivore insects and their natural ... [more ▼]

The effects of global atmospheric changes on vegetation and associated insect populations are increasingly studied, but how these gases affect the interactions between herbivore insects and their natural enemies is less clear. As the efficacy of natural enemies is governed largely by behavioral mechanisms, changes in the behavior of insect prey defenses can change the dynamics of insect populations. The impact of increases in atmospheric carbon dioxide (CO2) concentrations on aphid population dynamic is well documented. However, few publications about their chemical ecology are reported. Aphids are using many chemical signals to communicate with each other or with their environment. For example aphids produce an alarm pheromone to signal the presence of a natural enemy in the colony. For our experiments, aphids Acyrthosiphon pisum (Harris) were reared on Vicia faba L. in home-made Plexiglas® chambers, allowing us to control the CO2 concentration, temperature and humidity. Aphids were reared under both ambient (aCO2 ≈ 400 ppm) and elevated (eCO2 ≈ 800 ppm) CO2 concentration for several generations. Here we quantified the emission of (E)-β-Farnesene (EβF - main compound of alarm pheromone) released by predated aphids reared under ambient or elevated CO2 concentration, with two different methods: a real-time analysis, and the total amount analysis. The EβF content of whole aphid bodies was also analyzed, as well as the escape behavior of aphid colony according to the growing conditions of aphid populations. These results will be discussed in terms of biological control in future climate. [less ▲]

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See detailTuta absoluta (Lepidoptera: Gelechiidae) development on wild and cultivated plant species
Bawin, Thomas ULg; Dujeu, David ULg; Fagan, Maud et al

Conference (2015, August 24)

Introduction: The tomato leafminer, Tuta absoluta (Lepidoptera: Gelechiidae), is a widespread invasive species damaging economically important solanaceous crop plants, including tomatoes and potatoes ... [more ▼]

Introduction: The tomato leafminer, Tuta absoluta (Lepidoptera: Gelechiidae), is a widespread invasive species damaging economically important solanaceous crop plants, including tomatoes and potatoes. Little is known about the ability of the microlepidoptera to encounter and develop on alternative wild and agricultural plant species. These plants could provide refuges and have to be identified for more efficient integrated management strategies. Objectives: In the present study, we assessed under laboratory conditions the ability of T. absoluta to develop on such plant species referred as potential hosts in the literature, including Solanaceae, Chenopodiaceae, Convolvulaceae, Fabaceae, and Malvaceae. Materials and methods: For each plant species, fitness tests were performed in Petri dishes by isolating single individuals with excised leaf. Two choice behavioral assays were performed in flying tunnels. Volatile organic compounds released by solanaceous plants were trapped using a dynamic collection system, and analyzed by GC-MS. Results: We found that Solanum species allowed higher larval survivability and shorter development time (from egg to adult emergency) compared to the other plants. Non-solanaceous plants were not able to sustain T. absoluta larvae. Two choice behavioral assays revealed that adult distribution and female oviposition did not differ between Solanum species, which were preferred to other tested solanaceous plants. The hypothesis that female host plant choice is influenced by plant volatile organic compounds was tested. Solanum volatile profiles showed similarities, and were presenting quantitative and qualitative differences with the other tested solanaceous plants, providing some explanations in the observed behavioral discrimination. Further electrophysiological and behavioral assays are required to confirm the effect of specific chemicals on the choice of the oviposition site in T. absoluta. Conclusion: It can be concluded that Solanum species are the more suitable hosts for T. absoluta development. Other solanaceous plant species could be opportunistically colonized with little incidence but care should be taken in these results as genetic variability in insects and plants, as well as plant physiological state, might have an impact on the pest survivability. [less ▲]

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See detailDoes elevation in atmospheric CO2 concentration impact aphid alarm signaling?
Boullis, Antoine ULg; Appeldoorn, Claire; Oostrom, Marjolein et al

Poster (2015, August 24)

The effect of global atmospheric changes on interactions between vegetation and phytophagous insects is well studied since several years, but how does these changes affect the interactions between ... [more ▼]

The effect of global atmospheric changes on interactions between vegetation and phytophagous insects is well studied since several years, but how does these changes affect the interactions between herbivore insects and their natural enemies is less clear. Impact of an increase in CO2 concentration on aphids is also well documented, but few publications focused on their chemical ecology. When endegered, aphids emit an alarm pheromone (generally composed of only one molecule: (E)-Beta-Farnesene) to induce an escape behavior in the colony. Here, we studied how an increase in CO2 concentration affects the alarm signaling mechanisms of the aphid Acyrthosiphon pisum, focusing on the production, the emission (under attack) and the perception of this signal. [less ▲]

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See detailCould alternative solanaceous hosts act as refuges for the tomato leafminer, Tuta absoluta?
Bawin, Thomas ULg; Dujeu, David ULg; De Backer, Lara ULg et al

in Arthropod-Plant Interactions (2015), 9(4), 425-435

The tomato leafminer, Tuta absoluta (Lepidoptera: Gelechiidae), is a widespread devastating pest reported to develop on economically important solanaceous plants. The characterization of its effective ... [more ▼]

The tomato leafminer, Tuta absoluta (Lepidoptera: Gelechiidae), is a widespread devastating pest reported to develop on economically important solanaceous plants. The characterization of its effective host range could help to understand and prevent the dispersion behavior of the insect in the environment. In this study, the ability of T. absoluta to locate and develop on wild (Solanum nigrum, Atropa belladonna, Datura stramonium) and cultivated (Solanum tuberosum) solanaceous plant species under laboratory conditions was assessed. Dual-choice behavioral assays performed in flying tunnels (S. tuberosum versus another plant) revealed that adult distribution and female oviposition did not differ between Solanum species, which were preferred to the other tested plants. The volatile molecules released by each tested plant species provide some explanations in the observed behavioral discrimination: S. nigrum and S. tuberosum volatile profiles were similar, and were presenting quantitative and qualitative differences with the other tested Solanaceous plants. To determine whether the host plant choice was adaptive or not, we have finally conducted fitness assays, by rearing T. absoluta larvae on each plant species and have shown that Solanum species allowed higher larval survivability and lower development time (from egg to adult emergency) compared to the other plants. We conclude that Solanum species are suitable host plants for T. absoluta, but other Solanaceous plant species could be opportunistically colonized with fewer incidences. [less ▲]

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See detailTuta absoluta (Lepidoptera: Gelechiidae) development on wild and cultivated plant species
Bawin, Thomas ULg; Dujeu, David ULg; Fagan, Maud ULg et al

Conference (2015, May 19)

The tomato leafminer, Tuta absoluta (Lepidoptera: Gelechiidae), is a widespread invasive species damaging economically important cultivated solanaceous crop plants, including tomatoes and potatoes. Little ... [more ▼]

The tomato leafminer, Tuta absoluta (Lepidoptera: Gelechiidae), is a widespread invasive species damaging economically important cultivated solanaceous crop plants, including tomatoes and potatoes. Little is known about the ability of this microlepidoptera to encounter and develop on alternative wild and agricultural plant species. These plants could provide refuges and have to be identified for more efficient integrated management strategies. In the present study, we assessed under laboratory conditions the ability of T. absoluta to develop on such plant species referred as potential hosts in the literature, including Solanaceae, Chenopodiaceae, Convolvulaceae, Fabaceae, and Malvaceae. For each plant species, fitness tests were performed in Petri dishes by isolating single individuals with excised leaf. We found that Solanum species allowed higher larval survivability and shorter development time (from egg to adult emergency) compared to the other plants. Non-solanaceous plants were not able to sustain T. absoluta larvae. Two choice behavioral assays performed in flying tunnels revealed that adult distribution and female oviposition did not differ between Solanum species, which were preferred to other tested solanaceous plants. These results appeared to be consistent with survival rates and development times. Because larval survivability depends on the female’s oviposition choice, the hypothesis that host plant choice is influenced by plant volatile organic compounds has to be tested. Volatile organic compounds released by solanaceous plants were trapped using a dynamic collection system, and analyzed by GC-MS. Solanum volatile profiles showed similarities, and were presenting quantitative and qualitative differences with the other tested solanaceous plants, providing some explanations in the observed behavioral discrimination. Further electrophysiological and behavioral assays are required to confirm the effect of specific chemicals on the choice of the oviposition site in T. absoluta. It can be concluded that Solanum species are the more suitable hosts for T. absoluta development. Other solanaceous plant species could be opportunistically colonized with little incidence but care should be taken in these results as genetic variability in insects and plants, as well as plant physiological state, might have an impact on the pest survivability. [less ▲]

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See detailEfficiency of pheromone-based formulations against phytophagous pests
Fassotte, Bérénice ULg; Vandereycken, Axel ULg; Chevalier Mendes Lopes, Thomas ULg et al

Conference (2015, May 19)

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 attractant 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 lady beetles and hoverflies. Both compounds were encapsulated together in alginate gel beads. The blend efficiency was first evaluated through laboratory assays, and then in wheat and broad bean fields, by considering the abundance and diversity of aphids and their natural enemies. [less ▲]

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See detailWhat makes the invasive Harmonia axyridis so successful? Six years of research in Gembloux provide additional answers
Fassotte, Bérénice ULg; Durieux, Delphine ULg; Vandereycken, Axel ULg et al

Conference (2015, May 14)

Following the introduction of the invasive species Harmonia axyridis (Pallas) in Europe, many research works were conducted on its ecological, economic and social impacts. Recently, our team has been ... [more ▼]

Following the introduction of the invasive species Harmonia axyridis (Pallas) in Europe, many research works were conducted on its ecological, economic and social impacts. Recently, our team has been involved in the characterization of the behavioral traits making this lady beetle species so successful. The main conclusions of two PhD works will be shortly presented: (1) Through a six-year inventory performed in Belgian agroecosystems, we have demonstrated that H. axyridis has become well established and was among the most abundant aphidophagous predatory species, causing a severe depression of biodiversity, even if communities of aphid predators are still quite diversified. (2) The social issues associated with the establishment of overwintering aggregations in human constructions were also carefully investigated. We have demonstrated the importance of social interactions on the establishment and cohesion of the aggregates. Finally, we have demonstrated that the deposition of a set of saturated and non-saturated hydrocarbons on the surfaces where the lady beetles were settling on, allowed their conspecifics to follow their markings and join the group. [less ▲]

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

Conference (2015, May 13)

To date, volatile sex pheromones have not been identified in the Coccinellidae family; yet, various studies have suggested that such semiochemicals exist. Here, we collected volatile chemicals released by ... [more ▼]

To date, volatile sex pheromones have not been identified in the Coccinellidae family; yet, various studies have suggested that such semiochemicals exist. Here, we collected volatile chemicals released by virgin females of the multicolored Asian lady beetle, Harmonia axyridis (Pallas), which were either allowed or not allowed to feed on aphids. Virgin females in the presence of aphids, exhibited “calling behavior”, which is commonly associated with the emission of a sex pheromone in several Coleoptera species. These calling females were found to release a blend of volatile compounds that is involved in the remote attraction (i.e., from a distance) of males. Gas Chromatography Mass Spectrometry (GC-MS) analyses revealed that (–)-β-caryophyllene was the major constituent of the volatile blend (ranging from 80 to 86%), with four other chemical components also being present; β-elemene, methyl-eugenol, α-humulene, and α-bulnesene. In a second set of experiments, the emission of the five constituents identified from the blend was quantified daily over a 9-day period after exposure to aphids. We found that the quantity of all five chemicals significantly increased across the experimental period. Finally, we evaluated the activity of a synthetic blend of these chemicals by performing bioassays which demonstrated the same attractive effect in males only. The results confirm that female H. axyridis produce a volatile sex pheromone. These findings have potential in the development of more specific and efficient biological pest-control management methods aimed at manipulating the behavior of this invasive lady beetle. [less ▲]

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See detail10. Perspectives - 1. La Lutte contre les pucerons grâce aux odeurs: développement d'une formulation phéromonale
Fassotte, Bérénice ULg; Vandereycken, Axel ULg; Chevalier Mendes Lopes, Thomas ULg et al

in Watillon, Bernard; Bodson, Bernard (Eds.) Livre Blanc Céréales (2015, February 25)

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See detailBacteria may enhance species association in an ant-aphid mutualistic relationship
Fischer, Christophe ULg; Lognay, Georges ULg; Detrain, Claire et al

in Chemoecology (2015)

The mutualistic relationships between certain ant and aphid species are well known, the primary benefits being protection for the aphids and carbohydrate-rich honeydew for the ants. Questions remain ... [more ▼]

The mutualistic relationships between certain ant and aphid species are well known, the primary benefits being protection for the aphids and carbohydrate-rich honeydew for the ants. Questions remain, however, as to the exact semiochemical factors that establish and maintain such relationships. In this study we used a series of treatments and associated controls placed at the end of a two-way olfactometer to determine the degree of attractiveness of a complete plant-aphid-honeydew system as well as individual components of that system. Both the olfactometer branch selected by the black garden ant (Lasius niger), and the linear speed with which ants moved through the device, were measured. Study results showed that ants were attracted not just to the complete plant system and the honeydew itself, but also to the microbial flora in the absence of plant or honeydew, and specifically to a bacterium from the black bean aphid (Aphis fabae) honeydew, Staphylococcus xylosus. This bacterium produces a blend of semiochemicals that attract the ant scouts. This information suggests the presence of a naturally-occurring, reliable biotic cue for detection of potential aphid partners. This would have to be confirmed in natural conditions by further field experiments. Rather than being opportunistic species that coincidentally colonize a sugar-rich environment, microorganisms living in aphid honeydew may be able to alter emissions of volatile organic compounds (VOCs), thus significantly mediating partner attraction. A bacterial involvement in this mutualistic relationship could alter the manner in which these and similar relationships are viewed and evaluated. Future studies into mutualism stability and function among macroscopic partners will likely need to transition from a two-partner perspective to a multiple-partner perspective, and consider the microbial component, with the potential for one or more taxa making significant contributions to the relationship [less ▲]

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See detailLes vers à soie sauvages à Madagascar : Enjeux écologiques et socio-économiques
Verheggen, François ULg; Haubruge, Eric ULg; Bogaert, Jan ULg

in Entomologie Faunistique = Faunistic Entomology (2015), 68

We here introduce the book « The Malagasy silk moths: ecological and socio-economic challenges » published in 2013 by the Presses agronomiques de Gembloux (Belgium). This book reflects the achievements ... [more ▼]

We here introduce the book « The Malagasy silk moths: ecological and socio-economic challenges » published in 2013 by the Presses agronomiques de Gembloux (Belgium). This book reflects the achievements and scientific activities of the project "Sustainable Management and valorisation of the endemic silkworm Borocera cajani in forest areas in the Antananarivo region" funded by Commission universitaire pour le Développement (CUD - CIUF). [less ▲]

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