“You’re looking at the handiwork of an emerald ash borer beetle on a now dead ash tree from Michigan. The invasive beetles have killed tens of millions of ash trees across the U.S. and Canada.Cornelia Schaible/Getty Images
In 2012, a group of annoying outsiders invaded the tranquil climes of Connecticut. They weren’t New York City folks looking to build second homes but rather penny-sized bugs. Known as emerald ash borers, the iridescent beetles drilled holes and laid eggs in the ash trees so common in my home state. The insects killed thousands of trees by eating through them during each stage of their larval development [source: DEEP].
State environmental officials tried in vain to stop the beetles from spreading by instituting measures such as quarantining the sale of firewood. Yet, ridding the state of the emerald ash borer was easier said than done. By July 2014, the beetle had spread into 38 Connecticut towns and five of its eight counties [source: DEEP]. The emerald ash borer, which came most recently from Michigan, is just one of several unwanted species that have stung Connecticut in recent years.
Although I have yet to see an ash borer, I gird myself each summer for my annual battle against another outsider — the Japanese beetle. I bait several socklike traps every July and watch them fill up like so many colostomy bags with the corpses of the beetle. As one environmental official told me years ago, Japanese beetles, the gypsy moth and other nonnative plants and animals are called invasive for a reason: They just won’t let go.
Invasive species can be any type of living organism, as well as its seeds or eggs, that isn’t native to a particular ecosystem. When I lived on Lake George in the Adirondacks of New York, the alien species du jour was Eurasian watermilfoil, a plant from Europe and Asia. It grew from one small patch on the southern end of the lake all the way to its northern reaches, crowding out native plants, choking water systems, entangling boat propellers and making it difficult to swim or fish. A few miles away in nearby Lake Champlain, another invasive species, the lamprey eel, literally glommed on to fish, including salmon, sucking the lifeblood out of them [sources: Lake George Association, National Wildlife Federation].
Whether plant, bug, fish or otherwise, invasive species come in all shapes and sizes. They’re called variously alien species, exotic pests, nonindigenous species or nonnative animals, and they will not only wreck the environment but also destroy economies and make people sick, as the mosquitoes carrying West Nile virus do. They all grow and reproduce so quickly and aggressively that it is often hard to stop them [source: National Wildlife Federation].