In order to find out about its migrations, various research centres in South Africa, Sweden, Canada, Chile, Australia, Spain, Argentina and Switzerland have conducted research detailing its routes and expansion periods. A significant new fact has emerged and it is that the wasps returning to Europe from Chile and South Africa have undergone a genetic micro-evolution which makes them more resistant to their natural European enemy, a nematode that sterilises them.
The Sirex noctilio wasp is regarded as a secondary pest in Europe because in this geographical area there is a natural enemy preventing its spread on a large scale. It is a nematode that gets into the wasp's genital organs and sterilizes it. However, the wasp is a pest of great importance in the zones it has migrated to like Australia, South America and South Africa, where it does not have to contend with this natural enemy.
In the countries where it has been accidentally introduced, the insect can even kill a tree, because when the females lay their eggs inside the trunk, they also release a fungus and a toxic mucoid substance which kills off the specimen. As an example of its devastating effect, one can cite that in Australia it succeeded in killing 40% of the pine trees after it was introduced halfway through the last century.
The researchers want to make it quite clear that in Europe one must remain vigilant in the management of the Sirex noctilio. In the genetic analyses carried out, it has been discovered that samples originating in Chile and South Africa and which have been detected in Switzerland have undergone a genetic micro-evolution. This genetic modification makes them more resistant to the nematode that can render them sterile; so their capacity to reproduce and spread increases considerably. The specimens displaying this microevolution have an unknown genetic origin, even though specialists believe that they may have originated in Asia or North Afr
|Contact: Irati Kortabitarte|