Mountain Pine Beetle

The Mountain Pine Beetle, Dendroctonus ponderosae Hopkins, is an insect species with an large range extending across western North America from southern California to central British Columbia. Mountain Pine Beetles utilize pine trees to sustain their one year life cycles. As larvae they feed on the inner bark of the trees and emerge as adults in late summer. They then move to mate and females will seek out large pine trees to lay their eggs in. They will create a vertical tunnel under the bark and lay roughly 75 eggs. The eggs will hatch and over-winter under the bark by metabolizing glycerol which acts as an anti-freeze. They will continue to develop in the spring until the emerge as adults in the late summer to complete their life cycle.

A key part of this cycle is the ability of MPB to transmit bluestain fungi from their birth tree to their new host tree. The fungi grows within the tree and in concert with the beetle will kill the tree. The fungi will cause a blue-gray appearance to the sapwood.

Sources: http://www.ext.colostate.edu/pubs/insect/05528.html