Bumblebees look cute. They have a thick fur, fly somewhat clumsily and are less aggressive than honeybees or wasps. They are very much appreciated by farmers as keen pollen collectors. Particularly in the context of the crisis-stricken honeybee populations, the buff-tailed bumblebee, Bombus terrestris, is being bred on an industrial scale for the pollination of fruit and vegetable crops both inside and outside greenhouses.
It was hoped that these insects would take over these important services when they were first introduced into central Chile, in southern South America, in 1998 as pollinators in a few greenhouses, with the backing and approval of the state authorities. But in the greenhouse, they did not stay. Some individuals escaped and very soon they established colonies in the wild. But that was not all. The buff-tailed bumblebee turned out to be an extremely invasive insect that embarked on an unparalleled victory tour that took it as far as Patagonia. As an aside, the first European bumblebee species, Bombus ruderatus, was introduced back in 1982 but it turned out to be relatively harmless in comparison.
"This is one of the most spectacular examples of the invasion of an entire continent by a foreign species introduced by man", says Paul Schmid-Hempel, retired Professor of Experimental Ecology at ETH Zurich. He has been monitoring the spread of buff-tailed bumblebees over the last ten years. Together with this wife Regula and his colleagues from South America he has just published his work in "Journal of Animal Ecology". The couple collected these insects during several trips to southern South America in order to document their rapid spread, do genetic analyses and examine the parasites which accompany them as stowaways in the bumblebee intestines.
The findings show that the European buff-tailed bumblebee spread southwards from central Chile along the Andes at a ra
|Contact: Paul Schmid-Hempel|