1 School of Biological Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand
2 Scion (New Zealand Forest Research Institute), PO Box 29 237, Christchurch 8540, New Zealand
3 CONICET. Grupo de Ecologia de Insectos. INTA EEA Bariloche, (8400) Bariloche, Argentina
4 CABI Europe - Switzerland, Rue des Grillons 1, CH-2800 Delemont, Switzerland
5 Muséum National d’Histoire Naturelle, Département Systématique and Evolution, UMR 7205 OSEB, CP
6 Muséum National d’Histoire Naturelle, Département Systématique and Evolution
More than 30 vespid species have been introduced around the world, but the seven most invasive species are all eusocial. Most introduced Vespidae only occur in one or two countries, but some areas have become geographic hotspots of invasion; Hawaii (15 species), North America (8 species), New Zealand (5 species), Australia (4 species) and South America (4 species). Two invasive species, Vespula vulgaris and V. germanica have become particularly widespread and abundant with a range of impacts on biodiversity and ecosystem function. Other successful invasive species include several Polistes spp., which affect local biodiversity through direct predation or competition for food or space. Toxic baiting has been the most successful control strategy against invasive vespids to date. Several attempts at biological control using parasitoids have not successfully reduced invasive wasp populations, although the biocontrol agent has only established in one case. The social structure of colonies and their high reproductive efficiency has facilitated invasion by these species, but it also means management at the population level will be difficult. This emphasises the need to prevent such invasions from occurring in the first place.