<p>Mountain pine beetles infest <span class="taxon">Pinus</span> trees in western North American forests. While they can reach relatively high altitudes, their preference is for lower altitudes with suitable temperatures. Because instars (stages of larvae) of <span class="taxon"><em>Dendroctonus ponderosae</em></span> are susceptible to the cold, the beetles prefer to reside in areas with moderate temperatures. This limits the range of <span class="taxon"><em>D. ponderosae</em></span> with respect to both altitude and northern expansion.<span> (Safranyik, 2001)</span></p>  <p>With the increase of temperatures due to global warming, mountain pine beetle larvae are now capable of living through winter in areas farther north that were formerly too cold for their survival. In addition, the beetles have moved to higher elevations. The expansion of the mountain pine beetle range due to global warming has resulted in damage to <span class="taxon">Pinus</span> forests in previously unaffected locations.<span> (Logan and Powell, 2001)</span></p>  <p>Mountain pine beetles preferentially infest trees that are under stresses such as injury or disease, fire damage, old age, and overcrowding. These trees are also the first to die. If the beetle population gets large enough, <span class="taxon"><em>D. ponderosae</em></span> will infest healthier <span class="taxon">Pinus</span> trees in the area. As these trees die as well, entire populations of <span class="taxon">Pinus</span> trees become kindling for fires that can have drastic effects on the forest ecosystem.<span> (Leatherman, Mehall, and Aguayo, 2007)</span></p>  <p><strong>Habitat Regions: </strong>Temperate; Terrestrial</p><p><strong>Terrestrial Biomes: </strong>Forest</p>