Population genetic structure of Tomicus piniperda L. (Curculionidae: Scolytinae) on different pine species and validation of T. destruens (Woll.).
Genetic diversity and population structure of Tomicus piniperda was assessed using mitochondrial sequences on 16 populations sampled on 6 pine species in France. Amplifications of Internal transcribed space 1 (ITS1) were also performed. Our goals were to determine the taxonomic status of the Mediterranean ecotype T. piniperda destruens, and to test for host plant or geographical isolation effect on population genetic structure. We showed that T. piniperda clusters in two mtDNA haplotypic groups. Clade A corresponds to insects sampled in continental France on Pinus sylvestris, P. pinaster and P. uncinata, whereas clade B gathers the individuals sampled in Corsica on P. pinaster and P. radiata and in continental France on P. pinea and P. halepensis. Insects belonging to clade A and clade B also consistently differ in the length of ITS1. Individuals belonging to both clades were found once in sympatry on P. pinaster. Genetic distances between clades are similar to those measured between distinct species of Tomicus. We concluded that clade B actually corresponds to the destruens ecotype and forms a good species, T. destruens. Analyses of molecular variance ( amova ) were conducted separately on T. destruens and T. piniperda to test for an effect of either geographical isolation or host species. Interestingly, the effect of host plant was significant for T. piniperda only, while the effect of geographical isolation was not. Pine species therefore seems to act as a significant barrier to gene flow, even if host race formation is not observed. These results still need to be confirmed by nuclear markers.
Kerdelhué
Carole
C
INRA, Laboratoire de Zoologie forestière, Route de la Pomme de Pin, BP 20619 Ardon, F-45166 Olivet cedex, France. Carole.Kerdelhue@orleans.inra.fr
Roux-Morabito
Géraldine
G
Forichon
Julien
J
Chambon
Jean-Michel
JM
Robert
Annelaure
A
Lieutier
François
F
D000818:Animals; D001517:Coleoptera / Q000033:anatomy & histology / Q000145:classification / Q000235:genetics*; D021901:DNA, Intergenic / Q000032:analysis*; D004272:DNA, Mitochondrial / Q000032:analysis* / Q000235:genetics; D014644:Genetic Variation; D005828:Genetics, Population; D006239:Haplotypes; D021141:Nucleic Acid Amplification Techniques; D010802:Phylogeny; D028223:Pinus
D021901:DNA, Intergenic; D004272:DNA, Mitochondrial