http://www.digitaljournal.com/news/environment/invasive-bumblebess-and-the-decline-of-bees-in-chile/article/364010

Invasive bumblebees and the decline of bees in Chile

Posted Dec 15, 2013 by Tim Sandle
European bumblebees introduced into Chile in the late 1990s have proved to be invasive. This has resulted in a decline in the populations of many native bees to Chile and other regions of South America.
Worker buff-tailed bumblebee
Worker buff-tailed bumblebee
Alvesgaspar
The buff-tailed bumblebee, Bombus terrestris, has been bred on an industrial scale for the pollination of fruit and vegetable crops both inside and outside greenhouses. One area where they were introduced was Chile during the late 1990s. The purpose was for the bees to act as pollinators in a series of greenhouses.
One problem, according to ETHZ, was that some individuals escaped and very soon they established colonies in the wild. The bees have spread so far that they have been tracked to Patagonia. More detailed analysis has shown that the European buff-tailed bumblebee has spread southwards from central Chile along the Andes at a rate of around 200 kilometres a year. This is a much faster rate than scientists were aware.
The problem is that the advance of the European bumblebee has proved to be a disaster for the native bumblebees, with numbers of native bees declining significantly. For example, the attractive and vivid orange giant bumblebee Bombus dahlbomii has virtually disappeared. One likley reason for its extinction is the protozoan parasite, Crithidia bombi, which lives in the intestines of the buff-tailed bumblebee.
The spread of the bees has been reported in the Journal of Animal Ecology, in a paper titled “The invasion of southern South America by imported bumblebees and associated parasites”.