Jean-Claude graduated in Agricultural sciences and Forestry at the (at the time) Faculté des Sciences agronomiques de Gembloux, and his PhD at ULB was in forest entomology. He was a research associate at F.R.S. - FNRS, then became a professor at ULB. He is now retired but keeps a few things going on.
My main field of interest is the ecology, behaviour and control of forest insects. I am particularly interested in their reproductive strategies, natural enemies, relationships to their hosts, and spread. After decades of research, I must conclude that I have probably been ill advised to focus on particular scolytine species, sometimes awfully difficult to rear in the laboratory, instead of concentrating on particular problems to be tackled with easily cultured model species. But, nevertheless, the species I chose to study still fascinate me, as they are exemplary of fully divergent ecological strategies.
A first pet species, Dendroctonus micans is a “parasite” of spruce, whose females are usually fertilized by a brother and establish solitarily of healthy trees, which they do not kill and in which they are protected by the tree chemical and physical defenses against competitors and generalist natural enemies. D. micans is however usually fairly well controlled by a very specific predator, the Monotomid beetle Rhizophagus grandis, and we have actually mass-produced these predators during several decades and released them throughout France with perfect control success. We also have brought a batch of Belgian predators to the UK in the early eighties, in order for the British Forestry Commission to start its own rearing programme, which is still continuing.
A second species of choice, Ips typographus, is the most damaging forest pest in Europe. It regularly kills millions of spruces. It has the fascinating property to be able to shift from a scavenging state, at low population density to a predatory regime, when it kills trees. In both states, the insects behave collectively. When bound to scarce and unpredictable undefended, fallen trees, the young emerging adults disperse widely and search. As soon as a male has found a suitable host, it emits pheromones that attract one to four females but also attract one to four males, as the sex ratio is balanced upon emergence, and as the whole system relies on reciprocal spying. A trade-off of this system is that, because of the density needed in the air for at least one male to discover a tree, the trees are usually colonized at a density higher than the optimal density for maximizing individual brood. When sufficient resources (e.g. a sufficient provision of fallen trees after a storm) have allowed population growth above a certain theshold, and when all the undefended, fallen hosts have been exhausted, the beetles mass-attack living trees, which are colonized at even higher densities than fallen trees, in order to exhaust the tree defenses. Brood production per female is then even lower than on fallen trees, and this could lead to population decline. How this collective behaviour conflicts with individual fitness is an intriguing question indeed, and I am set to explore it further.
A second field of interest for me is pest risk assessment. I am a member of EFSA’s Plant Health panel, and have also been involved in risk assessments for the Belgian National Plant Protection Organization, the European and Mediterranean Plant Protection Organization (EPPO) and for ANSES (FR). I am presently conducting research on the risks for forest trees in Belgium of the pathogenic bacterium Xylella fastidiosa, originating from America and which has been found massively destroying olive trees in southern Italy (Apulia) since 2013 (see the Xyleris project, below). I am also interested in monitoring the presence in Belgium of the agents of the Thousand Cankers disease (the fungal pathogen Geosmithia morbida infecting Juglans spp. and vectored by the bark beetle Pityophthorus juglandis), originating from the US and recently established in central Italy (see the Fungifor project, below).
Colonization of weakened trees by mass-attacking bark beetles: no penalty for pioneers, scattered initial distributions and final regular patterns
E. Toffin, E. Gabriel, M. Louis, J.-L. Deneubourg, and J.-C. Grégoire. "Royal Society Open Science", Vol. 5, Issue 1, Pages 170454, 2018.
Monochamus species from different continents can be effectively detected with the same trapping protocol
C. K. Boone, J. Sweeney, P. Silk, C. Hughes, R. P. Webster, F. Stephen, L. Maclauchlan, B. Bentz, A. Drumont, B. Zhao, N. Berkvens, H. Casteels, and J.-C. Grégoire. "Journal of Pest Science", 2018.
The EFSA quantitative approach to pest risk assessment – methodological aspects and case studies
G. Gilioli, G. Schrader, J.-C. Grégoire, A. MacLeod, O. Mosbach-Schulz, T. Rafoss, V. Rossi, G. Urek, and W. van der Werf. "EPPO Bulletin", Vol. 47, Issue 2, Pages 213-219, 2017.
Spiny Prey, Fortunate Prey. Dorsal Spines Are an Asset in Intraguild Interactions among Lady Beetles
L. Hautier, G. San Martin, J.-P. Jansen, E. Branquart, and J.-C. Grégoire. "Frontiers in Ecology and Evolution", Vol. 5, 2017.
Effects of the wet catching method on the detection of Bursaphelenchus xylophilus from trapped longhorn beetle vectors
N. Berkvens, L. Waeyenberge, H. Casteels, N. de Sutter, M. L. Inácio, A. M. Fontes, C. Boone, J.-C. Grégoire, and N. Viaene. "Nematology", Vol. 19, Issue 6, Pages 671-680, 2017.
Is Prey Specificity Constrained by Geography? Semiochemically Mediated Oviposition in Rhizophagus grandis (Coleoptera: Monotomidae) with Its Specific Prey, Dendroctonus micans (Coleoptera: Curculionidae: Scolytinae), and with Exotic Dendroctonus species
L. Dohet, and J.-C. Grégoire. "Journal of Chemical Ecology", Vol. 43, Issue 8, Pages 778-793, 2017.
A risk categorisation and analysis of the geographic and temporal dynamics of the European import of plants for planting
R. Eschen, J. C. Douma, J.-C. Grégoire, F. Mayer, L. Rigaux, and R. P. J. Potting. "Biological Invasions", Pages 1-15, 2017.
Climate drivers of bark beetle outbreak dynamics in Norway spruce forests
L. Marini, B. Okland, Jönsson, B. J. Bentz, A. Carroll, B. Forster, J.-C. Grégoire, Hurling, L.-M. Nageleisen, Netherer, H. P. H. P. Ravn, A. Weed, and M. L. Schroeder. "Ecography", 2017.
Fallen trees' last stand against bark beetles
M. Louis, L. Dohet, and J.-C. Grégoire. "Forest ecology and management", Vol. 359, Pages 44-50, 2016.
Bacterial and fungal symbionts of parasitic Dendroctonus bark beetles
L. Dohet, J.-C. Grégoire, A. B. Berasategui, M. K. Kaltenpoth, and P. B. Biedermann. "FEMS microbiology, ecology", Vol. 92, Issue 9, 2016.
Modelling collective foraging in endemic bark beetle populations
M. Louis, E. Toffin, J.-C. Grégoire, and J.-L. Deneubourg. "Ecological modelling", Vol. 337, Pages 188-199, 2016.
Comparative multi-locus phylogeography of two Palaearctic spruce bark beetles: influence of contrasting ecological strategies on genetic variation.
F. Mayer, F. Piel, A. A. Cassel-Lundhagen, N. Kirichenko, L. Grumiau, B. Okland, C. C. Bertheau, J.-C. Grégoire, and P. Mardulyn. "Molecular ecology", Vol. 24, Issue 6, Pages 1292-1310, 2015.
Phytosanitary inspection of woody plants for planting at european union entry points: A practical enquiry
R. R. Eschen, L. Rigaux, L. L. Sukovata, A. M. A. M. Vettraino, M. M. Marzano, and J.-C. Grégoire. "Biological invasions", Vol. 17, Issue 8, Pages 2403-2413, 2015.
Trade patterns of the tree nursery industry in Europe and changes following findings of citrus longhorn beetle, Anoplophora chinensis Forster
R. R. Eschen, J.-C. Grégoire, G. G. M. Hengeveld, B. B. M. de Hoop, L. Rigaux, and R. P. J. R. P. J. Potting. "NeoBiota", Vol. 26, Pages 1-20, 2015.
Harmonia + and Pandora +: risk screening tools for potentially invasive plants, animals and their pathogens
B. B. D’hondt, I. Stiers, S. S. Quoilin, J. Cigar, A. Heughebaert, E. E. Branquart, S. Vanderhoeven, S. S. Roelandt, F. Mayer, V. V. Versteirt, T. Adriaens, E. Ducheyne, G. San Martin Y Gomez, and J.-C. Grégoire. "Biological invasions", Vol. 17, Issue 6, Pages 1869-1883, 2015.
Cold tolerance of the predatory ladybird Cryptolaemus montrouzieri
S. S. Maes, J.-C. Grégoire, and P. P. de Clercq. "BioControl", Vol. 60, Issue 2, Pages 199-207, 2015.
Economics and Politics of Bark Beetles
J.-C. Grégoire, K. F. K. F. Raffa, and S. B. S. Lindgren.
In "Bark Beetles: Biology and Ecology of Native and Invasive Species", Elsevier Inc., Pages 585-613. 2015.
Natural History and Ecology of Bark Beetles
K. F. K. F. Raffa, J.-C. Grégoire, and S. B. S. Lindgren.
In "Bark Beetles: Biology and Ecology of Native and Invasive Species", Elsevier Inc., Pages 1-40. 2015.
Flying the nest: male dispersal and multiple paternity enables extrafamilial matings for the invasive bark beetle Dendroctonus micans: Multiple paternity in sib-mating bark beetles
C. Fraser, O. Brahy, P. Mardulyn, L. Dohet, F. Mayer, and J.-C. Grégoire. "Heredity", Vol. 113, Pages 327-333, 2014.
Dispersal potential of native and exotic predatory ladybirds as measured by a computer-monitored flight mill
S. S. Maes, X. X. Massart, J.-C. Grégoire, and P. P. de Clercq. "BioControl", Vol. 59, Issue 4, Pages 415-425, 2014.
Prey range of the predatory ladybird Cryptolaemus montrouzieri
S. S. Maes, J.-C. Grégoire, and P. P. de Clercq. "BioControl", Vol. 59, Issue 6, Pages 729-738, 2014.
A semi-artificial rearing system for the specialist predatory ladybird Cryptolaemus montrouzieri
S. S. Maes, T. T. Antoons, P. P. de Clercq, and J.-C. Grégoire. "BioControl", Vol. 59, Issue 5, Pages 557-564, 2014.
Exploiting fugitive resources: How long-lived is "fugitive"? Fallen trees are a long-lasting reward for Ips typographus (Coleoptera, Curculionidae, Scolytinae)
M. Louis, J.-C. Grégoire, and P.-F. Pelisson. "Forest ecology and management", Vol. 331, Pages 129-134, 2014.
Large-scale risk mapping of an eruptive bark beetle – Importance of forest susceptibility and beetle pressure
S. Kärvemo, T. P. Van Boeckel, M. Gilbert, J.-C. Grégoire, and M. Schroeder. "Forest Ecology and Management", Vol. 318, Pages 158-166, 2014.
Ecosystem services of mixed species forest stands and monocultures: Comparing practitioners and scientists perceptions with formal scientific knowledge
M. Carnol, L. L. Baeten, E. E. Branquart, J.-C. Grégoire, A. Heughebaert, B. Muys, Q. Ponette, and K. Verheyen. "Forestry", Vol. 87, Issue 5, Pages 639-653, 2014.
Rapid increase in dispersal during range expansion in the invasive ladybird Harmonia axyridis
E. Lombaert, A. Estoup, B. Facon, Joubard, J.-C. Grégoire, A. Jannin, Blin, and T. Guillemaud. "Journal of evolutionary biology", Vol. 3, Pages 508-517, 2014.
Histoire de l'installation de quelques ravageurs
Thiéry, Vidal, N. Gauthier, Derridji, Vercambre, Goebel, J.-C. Grégoire, and F. Lieutier.
In "Interactions insectes-plantes, Interactions insectes-plantes", Quae & IRD, Pages 623-662. 2013.
Assessment of the functional role of tree diversity: the multi-site FORBIO experiment
K. Verheyen, Ceunen, Ampoorter, L. Baeten, Bosman, E. Branquart, M. Carnol, De Wandeler, J.-C. Grégoire, Lhoir, B. Muys, Nurlaya Setiawan, Vanhellemont, and Q. Ponette. "Plant ecology and evolution", Vol. 146, Issue 1, Pages 1-10, 2013.
Frost impacts on beech (Fagus sylvatica L.) susceptibility to scolytine ambrosia beetles
S. La Spina, C. De Cannière, A. Dekri, and J.-C. Grégoire. "Agricultural and forest entomology", Vol. 15, Issue 2, Pages 157-167, 2013.
Effects of Two Varieties of Bacillus Thuringiensis Maize on the Biology of Plodia Interpunctella
A. Gryspeirt, and J.-C. Grégoire. "Toxins", Vol. 4, Pages 373-389, 2012.
L’agroécologie : trajectoire et potentiel. Pour une transition vers des systèmes alimentaires durables..
P. Stassart, P. Baret, J.-C. Grégoire, T. Hance, M. Mormont, D. Reheul, D. Stilmant, G. Vanloqueren, and M. Visser.
In "Agroécologie. Entre pratiques et sciences sociales", Educagri éd., Dijon, Pages 25-51. 2012.
Lengthening of insect development on bt zone results in adult emergence asynchrony: does it influence the effectiveness of the high dose/refuge zone strategy?
A. Gryspeirt, and J.-C. Grégoire. "Toxins", Vol. 4, Issue 11, Pages 1323-1342, 2012.
Invasive alien predator causes rapid declines of native European ladybirds
H. Roy, T. Adriaens, N. Isaac, M. Kenis, T. Onkelinx, G. S. Martin, P. Brown, L. Hautier, R. Poland, D. Roy, R. Comont, R. Eschen, R. Frost, R. Zindel, J. Van Vlaenderen, O. Nedved, H. Ravn, J.-C. Grégoire, J.-C. de Biseau D'Hauteville, and D. Maes. "Diversity and distributions", 2012.
The influence of acclimation, endosymbionts and diet on the supercooling capacity of the predatory bug Macrolophus pygmaeus
S. S. Maes, T. T. Machtelinckx, P. P. de Clercq, M. M. Moens, and J.-C. Grégoire. "BioControl", Vol. 57, Issue 5, Pages 643-651, 2012.
Effectiveness of the High Dose/Refuge Strategy for Managing Pest Resistance to Bacillus thuringiensis (Bt) Plants Expressing One or Two Toxins.
A. Gryspeirt, and J.-C. Grégoire. "Toxins", Vol. 4, Issue 10, Pages 810-835, 2012.
Low temperature tolerance and starvation ability of the oak processionary moth: Implications in a context of increasing epidemics
N. Meurisse, G. Hoch, A. Schop, A. Battisti, and J.-C. Grégoire. "Agricultural and forest entomology", 2012.
Trees Wanted—Dead or Alive! Host Selection and Population Dynamics in Tree-Killing Bark Beetles
K. L. Kausrud, J.-C. Grégoire, O. Skarpaas, N. Erbilgin, M. Gilbert, B. Økland, and N. C. Stenseth. "PLoS ONE", Vol. 6, Issue 5, Pages e18274, 2011.
Population dynamics in changing environments: the case of an eruptive forest pest species.
K. L. Kausrud, B. Okland, O. Skarpaas, J.-C. Grégoire, N. Erbilgin, and N. C. Stenseth. "Biological reviews of the Cambridge Philosophical Society", Vol. 87, Issue 1, Pages 34-51, 2011.
Alkaloids provide evidence of intraguild predation on native coccinellids by Harmonia axyridis in the field
L. Hautier, G. San Martin Y Gomez, P. Callier, J.-C. de Biseau D'Hauteville, and J.-C. Grégoire. "Biological invasions", Vol. 13, Pages 1805-1814, 2011.
Larval performances, heterogeneous development and life cycle completion of the Siberian moth, Dendrolimus sibiricus (Lepidoptera: Lasiocampidae) on potential host plants in Europe: a laboratory study on potted trees
N. Kirichenko, J. Flament, Y. Baranchikov, and J.-C. Grégoire. "European journal of forest research", 2011.
Impact of poplar water status on leaf-beetle (Chrysomela populi) survival and feeding
S. La Spina, J.-C. Grégoire, P. Mertens, and C. De Cannière. "Annals of forest science", Vol. 67, Pages 209-214, 2010.
Epidémiologie des scolytes de l'épicéa et de leurs ennemis naturels.
J.-C. Grégoire, E. Hougardy, J.-M. Molenberg, and N. Warzée.
In "La forêt face aux tempêtes", Éditions Quae, Versailles, Pages 111-120. 2009.
Méthodes d’évaluation des attaques d'Ips typographus (Coleoptera, Scolytinae) en pessière.
J.-C. Grégoire, M. Gilbert, C. De Cannière, and Delplace.
In "La forêt face aux tempêtes", Éditions Quae, Versailles, Pages 77-99. 2009.
Native and exotic coniferous species in Europe – possible host plants for the potentially invasive Siberian moth, Dendrolimus sibiricus1 Tschtv. (Lepidoptera, Lasiocampidae)
N. I. Kirichenko, J. Flament, Y. N. Baranchikov, and J.-C. Grégoire. "EPPO Bulletin", Vol. 38, Issue 2, Pages 259-263, 2008.
A North American invasive seed pest, Megastigmus spermotrophus (Wachtl) (Hymenoptera: Torymidae): Its populations and parasitoids in a European introduction zone
A.-C. Mailleux, A. Roques, J.-M. Molenberg, and J.-C. Grégoire. "Biological Control", Vol. 44, Issue 2, Pages 137-141, 2008.
Kairomone traps: a tool for monitoring the invasive spruce bark beetle Dendroctonus micans (Coleoptera: Scolytinae) and its specific predator, Rhizophagus grandis (Coleoptera: Monotomidae)
N. Meurisse, D. Couillien, and J.-C. Grégoire. "Journal of Applied Ecology", Vol. 45, Issue 2, Pages 537-548, 2008.
Intraguild predation by Harmonia axyridis on coccinellids revealed by exogenous alkaloid sequestration
L. Hautier, J.-C. Grégoire, J. de Schauwers, G. S. Martin, P. Callier, J.-P. Jansen, and J.-C. de Biseau. "Chemoecology", Vol. 18, Issue 3, Pages 191-196, 2008.
Damage and control of BAWBILT organisms an overview
J.-C. Grégoire, and H. F. Evans.
In "Bark and wood boring insects in living trees in Europe, a synthesis", Springer, Pages 19-37. 2007.
Coniferous round wood imports from Russia and Baltic countries to Belgium. A pathway analysis for assessing risks of exotic pest insect introductions: Pathway analysis
F. Piel, M. Gilbert, C. De Cannière, and J.-C. Grégoire. "Diversity and Distributions", Vol. 14, Issue 2, Pages 318-328, 2007.
Predator/prey ratios: a measure of bark-beetle population status influenced by stand composition in different French stands after the 1999 storms
N. Warzée, M. Gilbert, and J.-C. Grégoire. "Annals of Forest Science", Vol. 63, Issue 3, Pages 301-308, 2006.
New occurrence of Ips duplicatus Sahlberg in Herstal (Liege, Belgium)
F. Piel, J.-C. Grégoire, and M. Knížek. "EPPO Bulletin", Vol. 36, Issue 3, Pages 529-530, 2006.
Post-storm surveys reveal large-scale spatial patterns and influences of site factors, forest structure and diversity in endemic bark-beetle populations
M. Gilbert, L.-M. Nageleisen, A. Franklin, and J.-C. Grégoire. "Landscape Ecology", Vol. 20, Issue 1, Pages 35-49, 2005.
Forecasting Cameraria ohridella invasion dynamics in recently invaded countries: from validation to prediction: A priori prediction of invasion dynamics
M. Gilbert, S. Guichard, J. Freise, J.-C. Grégoire, W. Heitland, N. Straw, C. Tilbury, and S. Augustin. "Journal of Applied Ecology", Vol. 42, Issue 5, Pages 805-813, 2005.
Occurrence of Ips typographus (Col., Scolytidae) along an urbanization gradient in Brussels, Belgium
F. Piel, M. Gilbert, A. Franklin, and J.-C. Grégoire. "Agricultural and Forest Entomology", Vol. 7, Issue 2, Pages 161–167, 2005.
Biological differences reflect host preference in two parasitoids attacking the bark beetle Ips typographus (Coleoptera: Scolytidae) in Belgium
E. Hougardy, and J.-C. Grégoire. "Bulletin of Entomological Research", Vol. 94, Issue 4, Pages 341-347, 2004.
Long-distance dispersal and human population density allow the prediction of invasive patterns in the horse chestnut leafminer Cameraria ohridella
M. Gilbert, J.-C. Grégoire, J. F. Freise, and W. Heitland. "Journal of Animal Ecology", Vol. 73, Issue 3, Pages 459–468, 2004.
Research on Parasitoids and Predators of Scolytidae – A Review
M. Kenis, B. Wermelinger, and J.-C. Grégoire.
In "Bark and Wood Boring Insects in Living Trees in Europe, a Synthesis", Springer Netherlands, Dordrecht, Pages 237-290. 2004.
Overview of development of an anti-attractant based technology for spruce protection against Ips typographus: From past failures to future success
R. Jakuš, F. Schlyter, Q.-H. Zhang, M. Blaženec, R. Vaverčák, W. Grodzki, D. Brutovský, E. Lajzová, M. Turčáni, M. Bengtsson, Z. Blum, and J.-C. Grégoire. "Anzeiger für Schädlingskunde", Vol. 76, Issue 4, Pages 89-99, 2003.
Site condition and predation influence a bark beetle's success: a spatially realistic approach
M. Gilbert, and J.-C. Grégoire. "Agricultural and Forest Entomology", Vol. 5, Issue 2, Pages 87–96, 2003.
Visual, semi-quantitative assessments allow accurate estimates of leafminer population densities: an example comparing image processing and visual evaluation of damage by the horse chestnut leafminer Cameraria ohridella (Lep., Gracillariidae)
M. Gilbert, and J.-C. Grégoire. "Journal of applied entomology", Vol. 127, Issue 6, Pages 354–359, 2003.
Spatial pattern of invading Dendroctonus micans (Coleoptera: Scolytidae) populations in the United Kingdom
M. Gilbert, N. Fielding, H. F. Evans, and J.-C. Grégoire. "Canadian Journal of Forest Research", Vol. 33, Issue 4, Pages 712-725, 2003.
Cleptoparasitism increases the host finding ability of a polyphagous parasitoid species, Rhopalicus tutela (Hymenoptera: Pteromalidae)
E. Hougardy, and J.-C. Grégoire. "Behavioral Ecology and Sociobiology", Vol. 55, Issue 2, Pages 184-189, 2003.
Marking bark beetle parasitoids within the host plant with rubidium for dispersal studies
E. Hougardy, P. Pernet, M. Warnau, J. Delisle, and J.-C. Grégoire. "Entomologia Experimentalis et Applicata", Vol. 108, Issue 2, Pages 107-114, 2003.
Dose-Dependent Response and Preliminary Observations on Attraction Range of Ips typographus to Pheromones at Low Release Rates
A. J. Franklin, and J.-C. Grégoire. "Journal of Chemical Ecology", Vol. 27, Issue 12, Pages 2425-2435, 2001.
Spatial distribution of ambrosia-beetle catches: a possibly useful knowledge to improve mass-trapping
J.-C. Grégoire, F. Piel, M. De Proft, and M. Gilbert. "Integrated pest management reviews", Vol. 6, Issue 3-4, Pages 237–242, 2001.
Past attacks influence host selection by the solitary bark beetle Dendroctonus micans
M. Gilbert, G. Vouland, and J.-C. Grégoire. "Ecological Entomology", Vol. 26, Issue 2, Pages 133–142, 2001.
Bark-beetle parasitoids population surveys following storm damage in spruce stands in the Vosges region (France).
E. Hougardy, and J.-C. Grégoire. "Integrated Pest Management Reviews", Vol. 6, Issue 3-4, Pages 163-168, 2001.
Recapture of Ips typographus L. (Col., Scolytidae) with attractants of low release rates: localized dispersion and environmental influences
A. J. Franklin, C. Debruyne, and J.-C. Grégoire. "Agricultural and Forest Entomology", Vol. 2, Issue 4, Pages 259-270, 2000.
Spruce stands provide natural food sources to adult hymenopteran parasitoids of bark beetles
E. Hougardy, and J.-C. Grégoire. "Entomologia Experimentalis et Applicata", Vol. 96, Issue 3, Pages 253-263, 2000.