The emerald ash borer (EAB) now faces a threat in the U.S. from native predators like the woodpecker. The destructive beetle has killed millions of ash trees from the East to the Midwest, causing billions of dollars in damage.
According to a study by Cornell University and the U.S. Forest Service, published in the September 2013 Biological Invasions journal, at least two bird species -- red-bellied woodpecker and white-breasted nuthatch -- have shown increases in population in areas severely affected by the ash borer as the destructive beetle has become a new food source for the birds.
Although the study indicates that the increased bird population may present some pressure on EAB, it will likely not be enough to stem its "explosive growth...but it does suggest that EAB spread might be faster were it not for the numerical increase of insectivorous birds resulting from the invasion."
Also having an impact on EAB are parasitic wasps, a natural predator, from northern China where the beetle orginated. According to Phys.org, after research three parasitic wasp species were released in the U.S. An article in the June Journal of Economic Entomology noted that one species was seeing an increase and expansion in Michigan, indicating that its growth was also in response to EAB and that the wasps would play a role in decreasing EAB population.
Discovered in Michigan in 2002, EAB have destroyed more than 25 million trees, according to the USDA.