The mountain pine beetle is a small cylindrical insect of the Rocky Mountains that attacks and kills mature trees by boring through the bark to feed on the wood of the tree. A key part of this cycle is the transmission of blue-stain fungi by the adults during colonization of the tree. The fungi growth disrupts the flow of water within the tree. The combination of the bark feeding beetle and the blue-stain fungi rapidly kills the lodgepole pine. While the mountain pine beetle has been part of a naturally occurring ecosystem, global warming conditions have seen populations of the beetle increase and spread.