A molecular study carried out on the chestnut gall wasp, Dryocosmus kuriphilus, has revealed the absence of genetic variability in this invasive species, a chestnut-tree parasite, in Europe. This is due to the fact that the wasp’s reproduction is strictly parthenogenetic, the females produce more females without having to be fertilized by a male. The high capacity of reproduction of the females, producing genetically identical daughters, give this insect a high invasive potential.