IDAHO FALLS, Idaho -

U.S. Forest Service officials say the number of trees being killed by pine beetle infestation is on the decline, in part because the insects have eaten themselves out of house and home.

The beetles burrow under the bark of pine trees to lay eggs. Once the eggs hatch, the larvae eat the inner layer of bark, killing the tree. An aerial survey in 2010 showed beetle-killed trees on 9.2 million acres of public and private land in Western states, including nearly 2 million in Idaho.

The number of infested acres in Idaho has dropped 63 percent in the years since.

Forest Service entomologist Carl Jorgensen told the Post Register the main reason for the decline is that the beetles have killed all the suitable hosts.