Final answer:
Most beetles, such as mountain pine beetles, cannot develop in wood with moisture content below about 20%, a crucial threshold for their survival and development. The correct option is B) 20%
Step-by-step explanation:
Most beetles, including mountain pine beetles which are prevalent in North America and Europe, do not develop in wood whose moisture content is below about 20%.
Environments with a moisture content below this threshold are not conducive to the survival or development of many beetle species.
This is critical information for understanding the factors that influence beetle populations, especially in the context of climate change which is affecting the survival rates of native bark beetles.
Climate change induces milder winters that allow beetles to overwinter, and longer summers allow for an additional generation. These changes can lead to extensive forest management and fire management problems, as seen with vast stretches of forests where a significant percentage of trees are killed by these beetles. The correct option is B) 20%