Spotted lanternflies (SLFs), an invasive species of insect native to parts of China and Vietnam, have become increasingly common both in the Washington, D.C.-Maryland-Virginia (DMV) area and on the Georgetown University campus.
First documented in Pennsylvania in 2014, SLFs have spread across the mid-Atlantic region as a highly invasive species whose behavioral habits and physiological characteristics pose threats to a number of plant and tree species. Since being spotted in D.C. for the first time in 2018, District residents have witnessed a noticeable increase in SLF presence — so much so that they are beginning to show up on meteorological radars.
Lucy Zipf, an ecologist and Georgetown professor studying the effects of climate change on biological communities, said SLF population numbers are increasing, potentially allowing them to spread more widely across the country.
“Large numbers of SLF in D.C. this year mean this species is on the move, expanding its range in the U.S.,” Zipf wrote to The Hoya. “In the U.S., quarantine zones have been established for SLF, these are regions where the movement of materials that may contain SLFs are limited.”
Braedan Lenehan (CAS ’28), an environmental biology major, said invasive species like SLFs often spread in non-native habitats as a result of human activity.
“Invasive species, plant or animal, appear in an environment where they don’t belong,” Lenehan wrote to The Hoya. “Most often, invasive species are caused by human activity, like the pet trade, or by accidentally taking species that stow away on shipping vessels. Invasive species can have devastating effects on their environments.”
Zipf said the 2014 arrival of SLFs in the United States occurred under unusual circumstances.
“This introduction event was unique in that the lanternflies were transported as egg masses,” Zipf wrote. “These egg masses can contain ~50 eggs, so many individuals were introduced to the U.S. at once.”
Martha Weiss, co-director of the environmental studies program and director of the environmental biology major, said the insect’s name is misleading.
“Despite their name, they are not flies; they are true bugs, in a group called planthoppers,” Weiss wrote to The Hoya. “They are quite pretty, up close — the immature stages (nymphs) start out black with white spots, and then become bright red; the adults have spotted and patterned beige and black forewings, and bright scarlet patches on their hindwings.”
Lenehan said his first experience with SLFs in his hometown of New York City (NYC) stuck out, as many people often resort to stomping on SLFs in order to kill them and help reduce their presence in the environment.
“I learned about spotted lanternflies a couple of years ago when I was walking back to my apartment in NYC, where I saw an older lady purposely squashing them,” Lenehan said. “I wondered why she was doing this, and soon after I got home, there was a notification on my phone about this invasion of spotted lanternflies in New York.”
Zipf said invasive species, like SLFs, can have negative impacts on the non-native environment to which they are introduced, including the destruction of surrounding plant life.
“SLFs for example cause direct and indirect damage to many commercially important plant species, like grapes,” Zipf wrote. “SLFs feed on a wide range of plant species, and cause damage and death as a result of their sap-sucking feeding behavior.”
Weiss said that, although stomping on adult lanternflies may help reduce the population size, there are more effective ways to prevent the spread of SLFs.
“Now that they’re here, there’s not a lot that we can do to eradicate them,” Weiss wrote. “The best thing we can do is learn to recognize the overwintering egg masses, which look like a beige clay patch about 1.5 inches in diameter, and remove those from trees, benches, cars, or other surfaces before they hatch in the spring,” Weiss said.
Weiss added that, despite the difficulty of eradicating invasive species, she would continue to support efforts to reduce the SLF population in the United States.
“I’d be happy to lead a lanternfly egg ID and eradication walk in early spring!” Weiss wrote.
