Abstract
The frequency and speed of the transport of goods and passengers have been on the increase for decades, involving a higher rate of introductions of animals and plants to new regions that they were not able to colonise unassisted. In particular, a large number of Hymenoptera have become introduced, either deliberately (for crop pollination purposes or pest control) or unintentionally. No global data are available, but a few regional examples may outline the size of the problem: 286 hymenopteran species are known to have been introduced into Europe (Rasplus et al. 2010), 148 into New Zealand (Landcare Research 2009), 35 into the Galápagos Islands (Causton et al. 2006) and 28 into the Canary Islands (Báez & Oromí 2010).