Cost of biological invasions; contribution from insects

Assessing the cost/benefit of invasive species is one way of raising awareness of prevention and control methods among the various stakeholders in society. In order to do so, economists and ecologists were required to work together, something that proved quite difficult at the outset, since their two specialities differ so much.

One of the first people to tackle this question was David Pimentel, now Professor Emeritus (entomology, ecology and evolutionary biology) at Cornell University (US). In one of his most recent publication (Pimentel, 2005), he assesses the costs related to invasive species in the United States, compiling the known costs of crop protection, the damaged suffered, invasive species rates, and so on.

90% of the total cost identified is linked to plants, arthropods (mainly insects), micro-organisms and invasive mammals. What are the annual costs? How many species are taken into consideration?