An army of rice-grain-sized beetles, attracted by warming weather, has moved into Canada's western forests, where its tree massacre is causing the mercury to rise yet further, a new study says. The voracious horde of mountain pine beetles has invaded about 65,000 square miles -- a fifth of the forest area of British Columbia, Canada's western-most province.
The beetles lay their eggs under the bark of pine trees, at the same time injecting a fungus that protects their offspring but kills the trees with the help of the larvae eating their insides. As trees are felled, the cooling effect of their transpiration, similar to human sweating, is also lost. The researchers measured a corresponding rise in summertime temperatures -- about 1.8 degrees Fahrenheit over the affected areas.