Year of the Beetle

In our last article, we looked at the unprecedented diversity and ecological functions beetles provide to the rest of us living here on Earth. If we consider only natural ecosystems within their proper places, the influence beetles have on the environment is overwhelmingly positive, be it pollinating plants, consuming dead, decaying material, keeping other species in balance through predation or acting as a food source themselves for other organisms.

But the world is constantly changing. Human beings have accelerated ecological change by altering habitats, influencing climate and embracing a system of global trade. We move a lot of stuff around; by land and by air, but mostly by sea. Cargo ships are sailing between continents with tens of thousands of tons of products and materials. History has proven these container ships to be an effective, if unwanted, vehicle for moving plants and animals to distant shores, often with catastrophic results.

Enter the Emerald Ash Borer to your backyard. This metallic green beetle measuring ½-inch in length is native to Asia. It was first discovered in North America in the forests of Michigan in 2002, munching away on native ash trees. Researchers believe the first EAB smuggled themselves in wood packing material from Asia. With no natural predators and millions of acres of forests that had no natural defenses against it, EAB quickly made itself at home. Today, the beetle has been documented in 35 states, including North Carolina since 2013, and several Canadian provinces. It ranges as far south as Texas and as far west as Colorado and it has wrought destruction wherever it goes.

By disrupting the flow of nutrients and water underneath the bark layer of ash trees, the larval stage of EAB has killed hundreds of millions of trees and cost hundreds of millions of dollars in losses to timber related industries.

For a time it was hoped the spread of EAB could be slowed by prohibiting the transfer of firewood from infected areas of the country to uninfected, but the strategy has proven ineffective and the spread continues. Scientists hope a solution can be found in treating some localized stands of ash trees with pesticides. A tiny, parasitic wasp from EAB’s home turf might also slow the spread long enough for North American ash tree species to evolve some defense against the beetle.

Unless that happens, however, the future is bleak for the continuing existence of ash trees in our forests. All thanks to a green beetle that’s no bigger than a thumbtack