Genetic characterization of the invasive populations of Vespa velutina in France M.ARCA 1,2, C.CAPDEVIELLE-DULAC DULAC 1, C.NADEAU 1, C.VILLEMANT 3, G.ARNOLD 2, J.F. SILVAIN 1 (1) IRD, UR 072, Laboratoire Evolution, Génétique et Spéciation, UPR 9034, CNRS 91198 Gif-sur-Yvette, and Université Paris-Sud 11, 91405 Orsay, France. (2) LEGS, Laboratoire Evolution, Génome, Spéciation, UPR 9034, CNRS 91198 Gif-sur-Yvette, and Université Paris-Sud 11, 91405 Orsay, France. (3) Muséum national d Histoire naturelle, Laboratoire d Entomologie, UPRESA 8043 du CNRS,45 rue Buffon, F-75231 Paris cedex 05 Apimondia 2009, Montpellier, France, 15-20 September
Introduction More and more alien species are being introduced unintentionally outside their natural habitats because of the increasing rate of trade and travel in the world. the level of genetic diversity within alien populations has received increasingly attention as an important factor influencing the survival and adaptive potential of founders Determining the source locations of these alien invasive species is a key step in the development of invasive species management strategies: to identify pathways of introduction to identify potential biological control agents The origin of many alien species remains uncertain because of the lack of historical data
Distribution range of Vespa velutina 2004 V. velutina Vespa velutina http://inpn.mnhn.fr/ From northern India to the Indochinese Peninsula, Taiwan and Indonesia
Study Objectives To genetically trace the history of the introduction of invasive species V. velutina in France Several independent introductions from Asia or single introduction event? What is the geographical origin of the French population? Is the introduced population genetically structured? Two types of molecular markers were used: mitochondrial markers and microsatellite markers.
Mitochondrial markers Materials and methods 50 individuals analysed : V. velutina (France, Indonesia,, Vietnam, China) V. crabro (France, Europe) Other species of the genera Vespa, Vespula and Dolichovespula Map showing the localities sampled in our study V. velutina V. crabro Markers: Cyt B: amplified with primers (BGLIIF/BGLIIR) previously used for V. crabro (Sheppard et al. 1994) COI: amplified with universal primers barcode (LCO-1490/HCO 1490/HCO-2198) Methods: Sequencing Sequence Alignments (BioEdit Sequence Alignment Editor 7.0.0) Construction of phylogenetic trees using parsimony method (PAUP* 4.0b10 ) Bootstrap analysis (1000 replications) Samples provided by: Samples provided by: T. Ken, Chinese Academy of Science C. Villemant & Q.Rome, Muséum national d Histoire naturelle L. Dvorak (Slovak Academy of Sciences, Czech Republic)
Cytochrome b Mitochondrial markers Results COI 0.007 0.013 0.013 Vespa velutina 0.040 0.143 0.005 Vespa crabro CytB: V.v. France = V.v. Chine V.v. Vietnam V.v. Indonésie COI: V.v. France V.v. Chine V.v. Vietnam V.v. Indonésie What is the geographical origin of the French population? no answer for the moment Vespa orientalis Mithocondrial markers can give us information only on a large scale because the low genetic variability => Need to develop nuclear markers for more information
Test of microsatellite loci developed for other species of Hymenoptera: Apis mellifera 96 markers tested none are polymorphic forvespa velutina Vespa mandarinia (Hasegawa et al,, 2002) 55 markers tested 2 are polymorphic forvespa velutina Vespula vulgaris (Daly et al, 2002) 16 markers tested 5 are polymorphic forvespa velutina 7 microsatellite loci were polymorphic in Vespa velutina Screening to isolate specific microsatellite loci for V. velutina The screening was successful: approximately 500 positive clones were isolated (120 already sequenced) 8 new loci were polymorphic in Vespa velutina 15 loci in total in total were genotyped in 84 V.velutina individuals Microsatellites 57 from France 15 from China 8 from Vietnam 4 from Indonesia
Microsatellites Study of the genetic structure of V. velutina population in France Descriptive statistical data analysis Construction of an individuals Neighbor-Joining tree from inter-individual individual distances based on the proportion of shared alleles DAS (POPULATIONS v.1.2.30) Analysis of the structure of the populations via a Bayesian method (STRUCTURE v2.2): to infer the number of K populations (clusters) in the microsatellite dataset to assign every individual a probability of membership in each of the clusters
Microsatellites Descriptive statistical data analysis : results 16 16 14 14 13 13 12 N Alleles 10 8 6 9 8 6 7 8 9 10 8 7 8 4 3 2 0 List 2003 VMA8 VMA6 LIST2018B LIST2004B LIST2015 LIST2020B D2185 D315 R4100 R4114 R1137 R1158 R1169 R433 Number of alleles per locus 7 6 5 4 3 57 6 15 France Vietnam Indonesie Chine 2 4 1 0 France Vietnam Indonesie Chine Average number of alleles per sampled country
Microsatellites Individuals Neighbor-Joining tree FRANCE Microsatellites Arbre d individusd Chine, Yunnan Wuding VIETNAM CHINE Mengzi Kunming Jianchuan INDONESIE The microsatellite tree (based on 15 loci) separated the 84 individuals of V.velutina into four main groups, according to their geographic origin.
Microsatellites Analysis of the structure of the populations via a Bayesian method (STRUCTURE v2.2) Simulation: several independent runs with different K values France China K=1 Kunming Mengzi Wuding Jianchuan K=3 K=2 K=4 K=3 K=5 No evidence for geographical substructuring of genetic variability in France 3 sub-populations in China
Conclusions The area of origin of the population introduced in France has not been (yet) determined No evidence was found of a geographic structuration of the genetic variability in France This result is probably due to a single introduction event Variability of the studied loci in French population: Introduction of several queens? Introduction of a single queen mated by several males?
Perspectives Continue the search of the area of origin of the population introduced in France Obtaining more samples from the area of origin Comparing the genetic diversity of V. velutina between French introduced population end populations from the (supposed) area of origin Monitor the genetic variability of the introduced population in the invasion front What is the expansion potential of the introduced species? What are the mechanisms of adaptation in the new environment? Is there any particular (selected) allelic combination? Make use of the microsatellite markers for studying the reproduction strategy of V. velutina How many males mate a female? Is there a worker queen conflict over male production?
Acknowledgements T. Ken (Chinese Academy of Sciences) L. Dvorak (Slovak Academy of Sciences) Q. Rome (Mus( Muséumum national d Histoire naturelle) Mr. Barnier, Bérard, Boivin,, Bontemps, Borie, Bretel, Ceyral, Devecis, Dufour, Dugrand, Duret, Devaux,, Jacob, Martrenchar, Montribot, Neyrat, Puga