Lutte biologique et écologie spatiale                                                  Biological control and Spatial Ecology
ACTUAL RESEARCH
FEBRUARY 2010


Research activites of the Biological control and Spatial Ecology Laboratory (LUBIES) deal with demographic and spatial changes in several harmful organisms such as forest, agricultural and urban insect pests and animal diseases. LUBIES focuses on the mechanisms which trigger outbreaks and epidemics, on the factors favoring their spread and persistence, and on the development of monitoring and control methods. A particular attention is given to invasive alien organisms: emerging diseases (bird flu, bovine tuberculosis, bluetongue) and exotic insects (forest and urban tree pests), and to the patterns and processes involved in their extension (global change, farming systems, trade).

Our study "oak processionary moth" is performed with the financial help of  the Institute for the encouragement of Scientific Research and Innovation of Brussels (ISRIB), in collaboration with the Brussels Institute for the management of the environment (IBGE). First, it aims at analyzing the causes and the modalities of the geographical and demographical expansion of the species (climatic influences, abundance and local availability of resources, natural enemies). Second, it intents at defining survey and control strategies adapted to urban and peri-urban areas. 

Involved researchers:
- Prof. Jean-Claude Grégoire, Head of the Laboratory : fundamental and applied aspects of ecology and behaviour of forets insects.
- Prof. Marius Gilbert, Research associate FNRS : spatial dynamics of invasive organisms, including pathogens and insects.
- Dr. Nicolas Meurisse, post-doctoral researcher (ULB/IRSIB) : ecology of forest insects.


Geographical distribution
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A synthesis of the geographical distribution of the oak processionary moth is currently achieved. At the European scale, it bases on historical records (museum specimens, data bases) to show the alternance of successive colonization and de-colonization events. Such pattern in population dynamics is particularly striking in North-Western Europe (e.g. in Belgium and the Netherlands). On a more restrained spatial and temporal scale, a detailed synthesis of recent records in Belgium is also performed.


Population dynamics (experimental)
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The cold tolerance of the oak processionary moth in winter (eggs) and in spring (caterpillars)   is investigated in laboratory conditions. We also determine thermal requirements for insect development. These are useful to perform risk analyses, related to the spatial progression of the species and hypothetical climatic changes. At last, the dispersal ability of the adults (moths) could be estimated basing on appropriate devices (flight mills).


Population dynamics (analytical)
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The historical data show outbreaks and declines of oak processionary populations in several countries in North-Western Europe (Belgium, The Netherlands, Germany, France). We are here using external well-documented data sets to estimate the speed of (re)-colonization of the territory by this species (Netherlands: data Alterra), or to show phenomenons of spatial synchrony (France: data Département Santé des Forêts). An extent of the study is the identification of favorable habitats for T. processionea, basing on models taking into acount some biotic (host plants) and abiotic parameters (altitude, climate)

Monitoring and risk inventory
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In the Brussels Region, a comparison of survey method for the oak processioneay moth was performed in 2008. New inventories are in mind for 2010, basing on nests observation (the most objective data to ascertain the local presence of the species). We will then map the distribution of the moth in the Region, and compare it to population density maps for risk inventory. The results of the study will be at disposal for local authorities (IBGE, communes).

Prospects in biological control

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Inventories of caterpillar colonies collected in Belgium, in France and in the Netherlands show high parasitism rates. These are mainly due to the presence of specialist tachinids (Pales processionea, Carcelia iliaca), and, in a lesser extent, to other generalist parasitoids (Compsilura concinnata, Psychophagus omnivorus, Pimpla sp.). The opportunity to set-up a method microbiological control, highly specific of T. processionea, is also under study (samplings of pathogenic organisms in selected European populations of the species).



Pictures (up to down):
  • Thaumetopoea processionea, male imago (F. Vilhelmsen)
  • Thaumetopoea processionea, third larval instar (N. Meurisse)
  • Pheromone trap, used for the capture of male moths (Edialux S.A.)
  • The tachinid fly Carcelia iliaca,  parasitizing T. processionea caterpillars (N. Meurisse)