A molecular study carried out on the chestnut gall wasp (Dryocosmus kuriphilus), a chestnut tree parasite, has revealed the absence of genetic variability in this invasive species in Europe. This is due to the fact that the wasp’s reproduction is strictly parthenogenetic—the females produce more females without fertilization by a male. This is the main conclusion of the research, published in Scientific Reports. The study was arried out by researchers from the INDEHESA Research Institute of the University of Extremadura, the University of Córdoba, CREAF and the CSIC-UCLM-JCCM Hunting Resources Research Institute.