The mountain pine beetles that have ravaged about 3 million acres of Colorado and southern Wyoming forests may be exhausting their primary food source — raising the prospect that the beetle epidemic could end, state and federal foresters said this week. Regeneration of decimated forests has begun as the U.S. Forest Service hires loggers to remove dead trees. “I think we’ve seen the worst of it,” said Sky Stephens, Colorado State Forest Service entomologist.