Nesting behavior of the paper wasp Polistes dominula in Central Europe-a flexible system for expanding into new areas

In North America, Polistes dominula causes a stir because it spreads very fast in this region upon its recent introduction. Many different explanations are presented in the literature why P. dominula is such a good invader. In Europe, the invasion of this species into northern regions is also on the rise. Since little is known about the nesting behavior of P. dominula in Central Europe, we investigated basic principles about nesting in Germany (latitude 49 degrees). We found out that foundress groups (one to four foundresses) and nests are smaller and that the nesting season is shorter than in other regions. The mean size of newly founded nests was 83 cells and we recorded an average length of nesting season of 4.6 months. The queens neither preferred single (54%) nor multiple founding (46%). The major benefit of multiple founding is an increased rate of survival. Only 47% of single-foundress colonies survived, whereas 100% of colonies that were built by more than two queens, survived. However, there was no impact of the number of foundresses on the productivity of colonies in terms of number of cells and pupae per nest. Furthermore, we observed that the length of the nesting season as well as the nest sizes varied greatly in three consecutive years depending on the climatic conditions of the preceding winter. These results imply that P. dominula is remarkably flexible and reacts very quickly to outside conditions. This adaptation could be one explanation for the rapid spread of this species into colder areas.