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United States Department of Agriculture

Agricultural Research Service

Research Project: DISCOVERY, BIOLOGY AND ECOLOGY OF NATURAL ENEMIES OF INSECT PESTS OF CROP AND URBAN AND NATURAL ECOSYSTEMS Title: Classical biological control of the olive fruit fly, Bactrocera olea (Diptera: Tephritidae), using the exotic parasitoie, Psyttalia lounsburyi (Hymenoptera: Braconidae) in France.

Authors
item Ris, Nicolas -
item Borowiec, Nicolas -
item Groussier-Brout, Geraldine -
item Thaon, Marcel -
item Warot, Sylvie -
item Auguste Maros, Alexandra -
item Malausa, Jean-Claude -
item Bon, Marie-Claude -
item Fauvergue, Xavier -

Submitted to: International Symposium on Biological Control of Arthropods
Publication Type: Proceedings
Publication Acceptance Date: November 1, 2012
Publication Date: May 30, 2013
Citation: Ris, N., Borowiec, N., Groussier-Brout, G., Thaon, M., Warot, S., Auguste Maros, A., Malausa, J., Bon, M., Fauvergue, X. 2013. Classical biological control of the olive fruit fly, Bactrocera olea (Diptera: Tephritidae), using the exotic parasitoie, Psyttalia lounsburyi (Hymenoptera: Braconidae) in France. Will the intraspecific hybridization improve the establishment of the biological control agents? International Symposium on Biological Control of Arthropods. 33-35.

Technical Abstract: The olive fruit fly, Bactrocera oleae (Rossi) (Diptera: Tephritidae) is an important pest of olives which is worldwide distributed and responsible for economic losses of approximately US$800 million per year. Since the 2000s both economical and environmental concerns have raised interested in classical biological control of this pest. The African endoparasitoid, Psyttalia lounsburyi (Silvestri) (Hymenoptera: Braconidae), has been targeted as one candidate biological control agent against this pest by the Californian Department of Food and Agriculture and the European Biological Control Laboratory. Since 2008, African populations of this parasitoid are being introduced repeatedly into California. Jointly the French Agency INRA developed a research project aiming at (i) introducing these African populations of the parasitoid into the southern part of France (ii) to assess more in depth the genetic diversity of these populations iii) to investigate to what extent intraspecific hybridization could contribute to improve the success of the establishment of the parasitoid as a result of an increase in the available genetic variability and /or the production of heterotic genotypes. Genetic studies based on one mitochondrial marker and eight microsatellite markers evidenced a genetic structure within the parasitoid’s African distribution. The two most differentiated populations in Kenya and South Africa were chosen for hybridization studies. Distribution and prevalence of Wolbachia in P. lounsburyi was also assessed for the first time. Two Wolbachia variants belonging to super-group A were detected, and the infection status varied significantly across populations and time. Owing to cytoplasmic incompatibilities, two aposymbiotic study populations of the parasitoid (one from Kenya and one from South Africa) were obtained and compared with their hybrids (F1 and back crosses) in the lab for several phenotypic traits. Results evidenced i) a relatively higher performance in terms of fitness of the south African population than the Kenyan population ii) hybrids did not outperform the two parental lineages iii) hybridization between parental populations is associated with a high variability in quantitative traits related to fitness. The results are discussed in light of the expected adaptability of the two parental populations and their hybrids in the field. 42,000 P. lounsburyi were mass reared and released for the first time in 2010 in 60 sites across southern France. Post release surveys evidenced that the parasitoid has been able to find his host but no recovery after the second winter.

Last Modified: 11/26/2014
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