Researchers from Dartmouth College in New Hampshire reported, "Climate change is not only giving destructive species new territory to prey on, it's creating a more lethal pest that can wreak havoc on forests."
“Native to the southeastern United States, the southern pine beetle, Dendroctonus frontalis Zimmermann is thriving as the climate warms. The pest is an icon of range expansions that are being permitted by climate change.” The beetles have moved from the southeastern U.S. into New Jersey, New York's Long Island, Connecticut, Massachusetts and now as far north as upstate New York, in 15 years.
Cooler fall and winter temperatures in the beetle’s new range are significantly increasing the population of beetles at the end stage of larval development and they all emerge at the same time as the weather warms. The concentration of developing individuals is called phenological synchrony.
The researchers said, “While not all species benefit from a large number of individuals in the same territory, the southern pine beetle relies on high population density to more effectively "bleed-out" pine trees. Coordinated mass-attacks on pine trees by beetles opens up additional resources, which can then support more beetles. This positive feedback can push the population into outbreak.”
The study has published a paper, Cool weather can amplify attacks of tree-killing bark beetle, in ScienceDaily, 31 May 2018 originally from the journal Oecologia.