Plagues of forest-destroying insects seem to arrive on our shores almost as regularly as ocean waves. Their names – hemlock woolly adelgid, emerald ash borer, Asian longhorned beetle, spotted lanternfly – only hint at the damage they trigger. The dead trees they leave behind cost billions to remove and add more than 5 million metric tons of carbon annually to the atmosphere, an amount roughly equal to the annual output of 4.4 million cars.
Yet for each major tree killer, around half a dozen foreign insects live quietly in our forests, causing few noticeable problems. A new study may help scientists pick out the future tree killers from the crowd, and it has a surprising conclusion: It’s the characteristics of the trees that insects feed on, not the insects themselves, that matter.