References of "Boullis, Antoine"
     in
Bookmark and Share    
Full Text
See detailClimate change and insect pests: Impact on carbon dioxide increase on aphid behavior and semiochemistry
Boullis, Antoine ULg

Doctoral thesis (2017)

There is no longer any doubt on the incidence of rising carbon dioxide (CO2) concentration on global change. Climate modifications are responsible of perturbations in interactions between living organisms ... [more ▼]

There is no longer any doubt on the incidence of rising carbon dioxide (CO2) concentration on global change. Climate modifications are responsible of perturbations in interactions between living organisms. This research topic is in the light of scientists since several decades and is considered to be of major interest in the understanding of future ecosystems’ functioning. In this prospect, interactions between insect herbivores and their natural enemies have received little attention under a climate change scope, while they are of paramount importance in the proper equilibrium of agro-ecosystems. As the efficacy of natural enemies is governed largely by behavioral mechanisms, changes in the predators’ behaviors but also in those related to prey defenses can change the dynamics of insect populations. As aphids are considered as one of the main crop pests in temperate regions, relative literature on impact of increases in atmospheric CO2 concentrations on aphid population dynamic now exists. However, few publications about their chemical ecology are reported. Aphids are using many chemical signals to communicate with each other or in their interactions with higher trophic levels. Here, I tempted to identify the impact of an increase in atmospheric CO2 concentration on the interactions between aphids and their natural enemies mediated by semiochemicals. Aspects of phytovirus transmission by aphids were also covered. After being involved in three literature reviews, I was interested in the aphid alarm signaling which strongly supports aphid-predators interactions. In the pea aphid Acyrthosiphon pisum (Harris), this signaling is mediated by a pheromone, namely the (E)-β-farnesene. For my experiments, I took into consideration the importance of all the steps that this molecule has to pass by, from its production into the emitter individual to the induced behavioral response of the receivers. The results obtained during these experiments highlighted an imbalance in aphid chemical communication for populations grown under elevated CO2 conditions, by modifications in several steps of the signal (decrease in pheromone production, emission and associated behavior). The results obtained here were supported by previous studies indicating that increases in CO2 concentration reduce the aphid escape behavior, which makes them potentially more susceptible to predation. We know that many plant pathogens are dependent on aphid dispersal to spread, so it is of major importance to predict how these insect vectors could be affected by forecasted climate. I thus carried my interest on the ability of aphids to transmit phytoviruses under changing atmosphere. Using another aphid model, the green peach aphid Myzus persicae (Sulzer), we have not observed any modifications in terms of virus and aphid spread in laboratory trials when tested under either actual or forecasted CO2 concentration. However, the viral transmission efficiency via aphids is increased under CO2-enriched atmosphere. Finally, the host searching behavior of an aphid predator was studied. The efficiency of natural enemies of insect pests is mainly driven by their ability to find food sources or oviposition sites in their environment. The conducted study highlighted the preference of the hoverfly Episyrphus balteatus De Geer towards aphid colonies grown under actual CO2 levels, suggesting modifications in chemical cues guiding hoverflies to a suitable oviposition site, due to increase of CO2. The results and knowledge obtained during these studies will add novel information on how a major component of climate change may impact tritrophic interactions and thus the efficiency of natural enemies of insect herbivores in biological control scope. [less ▲]

Detailed reference viewed: 26 (3 ULg)
Full Text
Peer Reviewed
See detailElevated carbon dioxide concentration reduces alarm signaling in aphids
Boullis, Antoine ULg; Fassotte, Bérénice ULg; Sarles, Landry ULg et al

in Journal of Chemical Ecology (2017), 43

Insects often rely on olfaction to communicate with surrounding conspecifics. While the chemical language of insects has been deciphered in recent decades, few studies have assessed how changes in ... [more ▼]

Insects often rely on olfaction to communicate with surrounding conspecifics. While the chemical language of insects has been deciphered in recent decades, few studies have assessed how changes in atmospheric greenhouse gas concentrations will impact pheromonal communication by insects. Here, we hypothesize that changes in the concentration of atmospheric carbon dioxide (CO2) affect the whole dynamics of alarm signaling in aphids, including: (1) the production of the active compound (E)-β-farnesene (Eβf), (2) emission behavior when under attack, (3) perception by the olfactory apparatus, and (4) the escape response. We reared two strains of the pea aphid Acyrthosiphon pisum under ambient and elevated CO2 concentrations for several generations. We found that an increase in CO2 concentration reduced the production (i.e., individual content) and emission of Eβf (released under predation events). While no difference in Eβf neuronal perception was observed, we found that an increase in CO2 strongly reduces the escape behavior expressed by an aphid colony following exposure to natural doses of the alarm pheromone. In conclusion, our results confirm that changes to greenhouse gases do impact chemical communication in insects, and could potentially have a cascade effect on interactions with higher trophic levels. [less ▲]

Detailed reference viewed: 79 (31 ULg)
Full Text
See detailOviposition deterring effect of Ocimum basilicum L. (Lamiaceae) on Tuta absoluta Meyrick (Lepidoptera: Gelechiidae)
Yarou, Boni Barthélémy ULg; Bawin, Thomas ULg; Boullis, Antoine ULg et al

Poster (2016, December 02)

Tuta absoluta Meyrick (Lepidoptera: Gelechiidae) is one of the most important pests of tomato, reducing crop yield in greenhouses and fields, in several countries around the world. Because synthetic ... [more ▼]

Tuta absoluta Meyrick (Lepidoptera: Gelechiidae) is one of the most important pests of tomato, reducing crop yield in greenhouses and fields, in several countries around the world. Because synthetic insecticides lead to resistance and have adverse effects on natural enemies and producers’ health, there is a need for alternatives. In this study, we assess the oviposition deterring effect of O. basilicum using dual-choice behavioral assays performed in flight tunnels. Two modalities were tested, i.e. (1) a tomato plant associated either with an O. basilicum plant versus a tomato plant associated with a plastic pot only filled with potting soil, and (2) a tomato plant with basil essential oil (EO) formulated in paraffin oil (PO) versus a tomato plant with PO only. A 1 ml cylindrical polyethylene plug loaded with 100 µl of solution (formulated EO or PO) was placed on each plant as a diffuser. Forty-eight hours after the release of unsexed adult individuals randomly sampled from the rearing in the central area of the tunnel, we found that plants and EOs reduced T. absoluta oviposition behavior on a nearby located tomato plant. GC-MS analyses showed that the major constituents include estragol (73.8%), linalool (8.6%), β-elemene (2.9%) in O. basilicum essential oils and E-α-bergamotene (38.9%), methyl eugenol (26.1 %), E-β-ocimene (17.7 % ) in O. basilicum VOCs collected with solid-phase micro-extraction method. These results suggest a valuable potential of O. basilicum and associated essential oils as component of an integrated management strategy against the tomato leafminer. [less ▲]

Detailed reference viewed: 54 (4 ULg)
Full Text
See detailComportement du puceron du pois face aux volatiles du basilic.
Yarou, Boni Barthélémy ULg; Boullis, Antoine ULg; Verheggen, François ULg et al

Poster (2016, October 22)

Les pucerons font partie des insectes qui causent des dégâts d’importances économiques sur une grande diversité de plantes cultivées. Les insecticides de synthèse généralement utilisés pour les contrôler ... [more ▼]

Les pucerons font partie des insectes qui causent des dégâts d’importances économiques sur une grande diversité de plantes cultivées. Les insecticides de synthèse généralement utilisés pour les contrôler montrent de plus en plus leurs limites (résistance), et sont néfastes pour l’homme et l’environnement. Dans la recherche de méthodes de lutte alternatives, le comportement de choix d’Acyrthosiphon pisum Harris (Homoptera : Aphididae) exposé à des sources d’odeurs de plant de fèves (Vicia fabae L.) et du basilic européen (Ocimum basilicum L.) à l’aide d’un olfactomètre en Y a été étudié. Les observations de cette expérience montrent que les pucerons se dirigent préférentiellement vers la source d’odeurs de fève et y passent plus de temps. Ce résultat montre que les volatiles du basilic ont un effet répulsif sur les pucerons du pois. D’autres tests seront évalués sur des espèces de pucerons plutôt généralistes afin de valider l’effet répulsif du basilic sur les pucerons. [less ▲]

Detailed reference viewed: 20 (3 ULg)
Full Text
Peer Reviewed
See detailWill climate change affect insect pheromonal communication?
Boullis, Antoine ULg; Detrain, Claire; Francis, Frédéric ULg et al

in Current Opinion in Insect Science (2016)

Understanding how climate change will affect species interactions is a challenge for all branches of ecology. We have only limited understanding of how increasing temperature and atmospheric CO2 and O3 ... [more ▼]

Understanding how climate change will affect species interactions is a challenge for all branches of ecology. We have only limited understanding of how increasing temperature and atmospheric CO2 and O3 levels will affect pheromone-mediated communication among insects. Based on the existing literature, we suggest that the entire process of pheromonal communication, from production to behavioural response, is likely to be impacted by increases in temperature and modifications to atmospheric CO2 and O3 levels. We argue that insect species relying on long-range chemical signals will be most impacted, because these signals will likely suffer from longer exposure to oxidative gases during dispersal. We provide future directions for research programmes investigating the consequences of climate change on insect pheromonal communication. [less ▲]

Detailed reference viewed: 55 (9 ULg)
Full Text
Peer Reviewed
See detailChemical Ecology of Aphids (Hemiptera: Aphididae)
Boullis, Antoine ULg; Verheggen, François ULg

in VILCINSKAS, Andreas (Ed.) Biology and Ecology of Aphids (2016)

Aphids are widespread insects considered as crop pest throughout the world. In order to control them, different techniques are known. The study of aphid-related semiochemicals is one topic recently ... [more ▼]

Aphids are widespread insects considered as crop pest throughout the world. In order to control them, different techniques are known. The study of aphid-related semiochemicals is one topic recently studied in integrated pest management, used to control aphid outbreaks. These semiochemicals include those involved in intraspecific communication, in communication among different trophic levels, those which attract or repel aphids, or those which enhance the efficiency of aphid natural enemies. This book chapter summarises the recent findings on aphid chemical ecology, from the discovery of molecules of interest, to their use in IPM methods. [less ▲]

Detailed reference viewed: 123 (39 ULg)
Peer Reviewed
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 ▲]

Detailed reference viewed: 97 (14 ULg)
Full Text
See detailDoes combining a wheat and pea mixture with methyl salicylate reduces aphid populations in both crops?
Chevalier Mendes Lopes, Thomas ULg; Fassotte, Bérénice ULg; Hatt, Séverin ULg et al

Conference (2015, August 25)

Aphids are important pests of wheat and pea. Among the alternative methods to control them with less reliance on insecticides, crop associations already proved to be efficient. However, if increasing the ... [more ▼]

Aphids are important pests of wheat and pea. Among the alternative methods to control them with less reliance on insecticides, crop associations already proved to be efficient. However, if increasing the chemical and structural complexity of vegetation can disrupt their host plants location, the searching efficiency of predators and parasitoids can also be reduced. Therefore, these beneficials may not always be more abundant in such systems. Combining crop associations with attractive semiochemicals for natural enemies can be interesting to solve this problem. In this research, we compared the effect of a wheat and pea pure stand, wheat and pea mixture, and wheat and pea mixture combined with methyl salicylate (MeSA) formulated in alginate gel beads, on the abundance and diversity of aphids and their natural enemies. These were weekly observed on plants during 2013 and 2014 growing seasons. Over these two years, significantly higher numbers of pea aphids (Acyrthosiphon pisum (H.)) were observed in the pure stand of pea compared with both mixtures (with and without MeSA). No significant differences were observed between treatments for wheat aphids (Sitobion avenae (F.), Metopolophium dirhodum (W.) and Rhopalosiphum padi (L.)), which were significantly less abundant than pea aphids. Aphid natural enemies were mainly observed on pea plants. Hoverfly larvae abundance was not significantly different between treatments during both years. The same phenomenon occurred with hoverfly pupae in 2013, while these were significantly more abundant in both mixtures compared with the pure stand in 2014. However, their number did not differ significantly between the mixture with and without MeSA. Few ladybirds and lacewings were observed. No significant differences were observed between treatments for parasitoid mummies in 2013. Their abundance was significantly higher in the pure stand of pea compared with both mixtures in 2014. Results from this study show that mixing wheat and pea is an efficient method to maintain aphid populations at a very low level on pea. The use of MeSA did not show significant effects on natural enemies. However, mixing these crops may be enough to reduce aphid populations under an acceptable threshold. [less ▲]

Detailed reference viewed: 70 (19 ULg)
Full Text
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 ▲]

Detailed reference viewed: 52 (3 ULg)
Full Text
Peer Reviewed
See detailClimate Change and Tritrophic Interactions: Will Modifications to Greenhouse Gas Emissions Increase the Vulnerability of Herbivorous Insects to Natural Enemies?
Boullis, Antoine ULg; Francis, Frédéric ULg; Verheggen, François ULg

in Environmental Entomology (2015)

Insects are highly dependent on odor cues released into the environment to locate conspecifics or food sources. This mechanism is particularly important for insect predators that rely on kairomones ... [more ▼]

Insects are highly dependent on odor cues released into the environment to locate conspecifics or food sources. This mechanism is particularly important for insect predators that rely on kairomones released by their prey to detect them. In the context of climate change and, more specifically, modifications in the gas composition of the atmosphere, chemical communication-mediating interactions between phytophagous insect pests, their host plants, and their natural enemies is likely to be impacted. Several reports have indicated that modifications to plants caused by elevated carbon dioxide and ozone concentrations might indirectly affect insect herbivores, with community-level modifications to this group potentially having an indirect influence on higher trophic levels. The vulnerability of agricultural insect pests toward their natural enemies under elevated greenhouse gases concentrations has been frequently reported, but conflicting results have been obtained. This literature review shows that the higher levels of carbon dioxide, as predicted for the coming century, do not enhance the abundance or efficiency of natural enemies to locate hosts or prey in most published studies. Increased ozone levels lead to modifications in herbivore-induced volatile organic compounds (VOCs) released by damaged plants, which may impact the attractiveness of these herbivores to the third trophic level. Furthermore, other oxidative gases (such as SO2 and NO2) tend to reduce the abundance of natural enemies. The impact of changes in atmospheric gas emissions on plant–insect and insect–insect chemical communication has been under-documented, despite the significance of these mechanisms in tritrophic interactions. We conclude by suggesting some further prospects on this topic of research yet to be investigated. [less ▲]

Detailed reference viewed: 112 (24 ULg)
Full Text
See detailImpact of Climate Change on “Aphid - Natural Enemies” Relationship
Boullis, Antoine ULg; Oostrom, Marjolein; Francis, Frédéric ULg et al

Poster (2014, December 12)

While the effects of global atmospheric changes on vegetation and associated insect populations (bottom-up interactions) are increasingly studied, how these gases affect the interactions between insects ... [more ▼]

While the effects of global atmospheric changes on vegetation and associated insect populations (bottom-up interactions) are increasingly studied, how these gases affect the interactions between insects and their natural enemies (top-down interactions) is less clear. As the efficacy of natural enemies is governed largely by behavioral mechanisms, changes in their prey-seeking behavior or the behavior of insect prey defenses can change the dynamics of insect populations. The impact of increases in atmospheric carbon dioxide concentrations on aphid population dynamic is well documented. However, nothing about their chemical ecology is reported in the literature. 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 (such as a predator or a parasitoid) in the colony. Moreover, this pheromone is used by natural enemies as a kairomone to locate aphid prey, and is thus at the center of aphid – natural enemies interactions. In this study, the impact of elevated CO2 concentration on the emission of the alarm pheromone in the aphid A. pisum is studied. Using a zNoseTM (Gas chromatograph enabling the fast analyze of the chemical composition of a sample), the kinetic of the EBF emission in real-time is set up for a single individual predated by a coccinellid predator Harmonia axyridis Pallas. This experimentation is done both for aphids reared under ambient atmospheric conditions and for individuals reared under elevated CO2 concentrations. We present the differences in terms of emission dynamic and discuss the potential of these results in terms of biological control. [less ▲]

Detailed reference viewed: 100 (14 ULg)
Full Text
See detailWill top-down interactions be affacted by climate change?
Boullis, Antoine ULg; Verheggen, François ULg; Francis, Frédéric ULg

Poster (2014, April 02)

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

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

Detailed reference viewed: 73 (11 ULg)