The spotted lanternfly is not that bad...
...and no, you don't need to squash it
When I first heard about an insect called the spotted lanternfly, perhaps via a 2018 New York Times story whose headline began “Lanternflies Eat Everything in Sight,” I was terrified. It sounded like the invasive pest to end all pests — the insect that would eat our forests to the ground.
Six years later, it’s clear that the feared lantern-pocalypse has not — and will not — come to pass. The lanternfly, a large, bumbling, polka-dotted insect that first touched down in southeastern Pennsylvania, has been munching its way through the mid-Atlantic and beyond for at least a decade now. But it’s not mowing down our forests. The insect’s largest impact seems to be on grape vines. But even here it seems like a story of localized damage more than the predicted destruction of the mid-Atlantic wine industry.
The lanternfly’s preferred host tree is tree of heaven, which is native to East Asia — as is the lanternfly. Tree of heaven, once planted as an exotic specimen, has become one of the most invasive trees in the world. Most nature-oriented people would probably love to see it eradicated from the United States — something that will never happen, lanternfly or not. At any rate, lanternflies devouring trees of heaven is hardly an ecological crisis.
The lanternfly has also been seen feeding on native trees, especially maples. Apparently there are reports of it killing walnut saplings. But unlike more host-specific pests such as emerald ash borer or hemlock woolly adelgid, the lanternfly isn’t wiping out whole species.
In fact, in a study published last year in which researchers exposed native hardwoods to high levels of lanternfly feeding, some trees grew less but no trees died, and trees recovered after the lanternflies were removed.
It’s worth keeping in mind that trees, as foundations of ecosystems, have lots of insects feeding on them all the time. It takes a lot more than ordinary feeding to merit major concern. And maples have arguably become overabundant in much of the eastern U.S., so something that takes them down a notch might not even be a bad thing.
At this point, it seems like the lanternfly’s main may be grossing out city dwellers. I’m not saying that’s a good thing. I’m a city dweller and I don’t relish being grossed out. But my and my neighbors’ comfort is probably not something to raise an alarm about — or devote precious public resources to.
(I will caveat this by noting that the lanternfly has not quite made it to the D.C. area, where I live. My only direct experience with lanternflies came on a trip to Lancaster County, Pennsylvania a few years ago, where within a few minutes of my getting out of the car, one landed on my leg. Perhaps I’ll change my tune if swarms of them start attacking the walnut tree and grape vines growing in my yard, or one gets on the Metro with me.)
But until then, I have good news to share. We can mostly stop worrying about spotted lanternfly! One less thing to worry about!
And yet, despite several years of growing scientific consensus, it’s clear that this message is not getting across — and is in fact running into resistance. Often when I log into Facebook, I see exhortations to squash every lanternfly in sight. (Admittedly, my Facebook feed may feature an above average amount of lanternfly-related material.)
The Washington Post recently ran a piece that doubled down on the “war against lanternflies” framing — and asserted that squashing them, while still recommended, “isn’t enough.” We also need to conduct a secondary war against tree of heaven, the piece asserts, to make lanternflies more palatable to birds.
I’ve been struck by how much people seem to crave these wars against parts of nature gone rogue. In a Facebook discussion that started when a local naturalist posted the Post piece, numerous people chastised me for suggesting that all the attention and resources directed toward the lanternfly may in fact be a harmful distraction from dealing with pests that actually do severe damage to native trees, such as emerald ash borer or beech leaf disease.
I’ve pondered why so many people are so devoted to hating the spotted lanternfly, and come up with several hypotheses. For one, it seems clear that motivated reasoning is playing a role. The endless fight against invasive species like the lanternfly seems to tap a deep desire to cleanse and restore a kind of primordial purity to a natural world that we see as disrupted and polluted by humans. Information that a new introduced species is dangerous affirms this existing worldview, so many nature-oriented people are motivated to accept the information. Information that said species is actually not so dangerous conflicts with the worldview, so people are motivated to dismiss it.
As a specific example, an article from Cornell’s agriculture college states “Spotted lanternflies do not appear to be damaging trees or most agricultural crops but are having an impact on grapes and some other crops.” To me, the salient point here is that lanternflies don’t damage trees or most crops — in other words, good news that we can take comfort in. But the naturalist who started the Facebook thread emphasized instead the impact on “grapes and some other [unidentified] crops.”
The war metaphor also seems to tap into a deep-seated need for enemies for us to unite against — something I recall George Orwell exploring in 1984. Now that direct conflict with armies of other nations has receded for most of us in the U.S. — a very good thing, to be sure — invading insects from those nations have perhaps become, for some, a substitute external threat that offers a sense of purpose and solidarity.
And in our complex world, people yearn for simple rules of thumb to follow. “All non-native/invasive species are bad” is a simple maxim. “Most non-native species are fine but a few are bad, and only by following the emerging science can we know which is which” is, well, not that simple.
But it’s increasingly clear that the latter is where science has arrived. While there is abundant evidence that certain non-native species can do great damage to natural ecosystems, most non-native species, including highly visible ones like the lanternfly, live here without causing major harm.
To be clear: An excessive antipathy toward spotted lanternflies is certainly not the most concerning instance of a group of people resisting or rejecting scientific information. It won’t cause unneeded illness and death (except of spotted lanternflies), as vaccine denialism does, or risk submerging our coastlines, as climate denialism could. It may cause unneeded stress and dead bugs on the sidewalk, but those aren’t the worst things in the world.
Still, it does have larger repercussions. The underfunded government agencies that are tasked with dealing with risks to plant health have devoted much of their limited funding and personnel to the lanternfly in recent years. That may have been a reasonable decision at first, when it wasn’t clear how bad the lanterfly would be. But I think it has persisted longer than necessary in part because the public has become convinced that the lanternfly was the worst invasive pest in the Mid-Atlantic, and agencies respond to public concerns. I doubt most people in the region could even name another tree-feeding insect.
Perhaps most concerning is what will happen next time a forest pest shows up. People who have gotten whipped up about the lanternfly will eventually learn that they’ve expended a bunch of emotional energy for no real reason. I would expect the response to the next pest to be much more muted.
If it’s another version of the lanternfly, that may be OK. But if it’s the next emerald ash borer, public apathy could lead to ecological disaster.
I think journalists have played a role in creating this situation, though I certainly wouldn’t place all the blame on them — TikTok has also contributed, as has Saturday Night Live. It’s just too tempting and too easy to whip readers into a frenzy with overblown headlines, especially when the “enemy” is big, brightly colored and easily seen. (I actually think the 2018 Times one was fine for its time, but the more recent Post one is way over the top — though once you get past the unpalatable war metaphors, the science in the story is actually quite interesting.)
The real message — that lanternflies are a nuisance but not a major threat — is comparatively boring and doesn’t make great copy. It doesn’t get the blood flowing.
I do want to commend my friend Nala Rogers for writing the best lanternfly story I’ve read to date, which both delves into some fascinating entomology and strikes a great balance. If you’re going to read one piece on the insect, read this one.
To its credit, the Times did, last September, start to question the utility of a war on lanternflies. One expert described squashing’s impact on the insect’s population as “marginal” but noted that it probably helps people feel “somewhat empowered.”
So if and when a lanternfly lands on you, feel free to enjoy it as an interesting, mostly harmless curiosity of nature — and then brush it off and go about your day.
This post has been updated from the original to include links to additional studies and news stories.
Nailed it! I’ve been waiting for someone to write this. Thanks!
Agreeing mostly. Also it may be that we live in a time when things just aren't allowed to be 'not that bad.'