What Are Lantern Flies Attracted To?

Spotted lanternflies are attracted to a surprisingly layered mix of cues: specific plant chemicals, short-wavelength light, tall vertical shapes, and even signals from other lanternflies already gathered in a spot. Their favorite host plant, the tree of heaven (Ailanthus altissima), is the single strongest predictor of where they show up, but the full picture involves smell, sight, and social behavior working together in ways researchers are still piecing apart.

Tree of Heaven Is the Primary Draw

If you want to understand where spotted lanternflies (SLF) congregate, start with the tree of heaven. A machine-learning study modeling lanternfly occurrence across Maryland found that the presence of tree of heaven was the single strongest predictor of whether they would be found in a given area, contributing roughly 28% of the model’s explanatory power.¹ That beats out temperature, land cover, and every other variable the researchers tested.

The relationship between SLF and tree of heaven deepens as the insects mature. Early-stage nymphs are generalists and will feed on a wide range of plants, but by the time they reach the fourth instar (the final nymphal stage before adulthood), they increasingly concentrate on tree of heaven.² This narrowing of host range over the insect’s life is one reason you might see tiny nymphs on all kinds of backyard plants in spring, only for the population to visibly shift toward tree of heaven by late summer.

Tree of heaven is not just a food source; it seems to function more like a performance enhancer. Lanternflies that feed on a combination of grapevines and tree of heaven develop faster, lay more eggs, and reach higher body mass than those fed on either plant alone. Grapevines on their own are actually a poor-quality host, with higher mortality and fewer eggs, but the addition of tree of heaven to the diet boosts fitness above what tree of heaven alone provides.³ For vineyard owners, this is bad news: the worst-case scenario is a property with both grapevines and tree of heaven nearby, because that combination creates ideal conditions for population growth.

Plant Smells That Pull Them In

Lanternflies do not simply stumble onto their host plants. They detect and follow airborne chemicals that plants release, and researchers have identified the specific compounds that matter most. The standout is methyl salicylate, a compound found in both tree of heaven and wild grapes. It is attractive to all life stages of SLF, from the smallest nymphs to adults, and it triggered the strongest overall response in lab behavioral tests.⁴ Field trials using methyl salicylate lures produced a two- to four-fold increase in trap captures compared with unbaited traps.

Two other plant-derived compounds also performed well in laboratory tests: (Z)-3-hexenol (a “green leaf volatile” that smells like freshly cut grass) and (E,E)-α-farnesene, a compound shared by grapes and tree of heaven. Interestingly, the youngest nymphs responded less strongly to these two than to methyl salicylate, suggesting that chemical preferences may shift slightly over an insect’s lifetime.

But the real finding that changes how researchers think about lures is that blends work better than any single compound. In olfactometer tests, SLF preferred multi-component mixtures over methyl salicylate alone, even when the methyl salicylate was presented at up to four times the concentration used in the blend.⁵ The best-performing blends combined methyl salicylate with 1-octen-3-ol, (Z)-3-hexenol, and (Z)-3-hexenyl acetate, sometimes with additional compounds. One blend in particular, designated “Blend 7B” by the researchers, was flagged as the most promising candidate for future field lure development. This makes intuitive sense: a real plant gives off dozens of compounds at once, so a cocktail that mimics that bouquet is more convincing than a single chemical shouting into the wind.

Another compound worth noting is sulcatone, which actually outperformed methyl salicylate in direct head-to-head lab comparisons.⁵ Sulcatone is a ketone found in a variety of plant tissues. Its strong performance suggests it could be a useful ingredient in next-generation traps, though the research on field deployment is still in early stages.

How They Sense These Chemicals

The sensory hardware behind chemical attraction has been studied at the neural level. Spotted lanternflies have a specialized organ on their mouthparts called the subapical labial sensory organ, and researchers mapped how individual neurons within it respond to a panel of dozens of odors. One particular neuron type, the B neuron, responded strongly to about 20% of the 85 odorants tested, with methyl salicylate emerging as the single most potent activator, reaching its saturation response at lower concentrations than any other compound tested. The neuron also responded to a range of phenolic compounds, aliphatic esters, and ketones.⁶ This neural evidence lines up neatly with the behavioral data: the compound that fires up their smell neurons the most is the same one that draws them to traps in the field.

Blue Light and Tall Shapes

Chemical cues are only part of the story. Spotted lanternflies also use vision to navigate their world, and their visual preferences are distinct. When given choices in a controlled arena, SLF of both sexes and all life stages consistently preferred ultraviolet light over white light. In experiments with colored lights, they lingered in blue light significantly longer than in white, yellow, or green.⁷ This attraction to shorter wavelengths (UV and blue) was consistent across every life stage tested. The practical takeaway: outdoor lighting that skews toward blue or UV may inadvertently draw lanternflies toward buildings and patios.

Shape matters too, sometimes more than you would expect. In one observation in eastern Pennsylvania, researchers documented several hundred actively dispersing lanternflies accumulating on a single telephone pole standing in a vineyard. The insects flying near the pole turned and landed on it from an average distance of about two meters away, apparently reacting to the tall vertical silhouette against the sky.⁸ The average height at which they made the turn was about eight meters. This visual behavior likely explains why SLF so often end up on tree trunks, utility poles, fence posts, and the corners of buildings. For them, a tall vertical object reads as a potential host tree worth investigating.

Skyscrapers as Deadly Magnets

The attraction to tall vertical shapes plays out in extreme fashion in cities. In downtown Philadelphia, researchers found adult lanternflies concentrated at the bases of skyscrapers and high-rises, most of them sluggish or dead. They also observed large numbers on the 27th floor of one building’s façade and on the roof of another.⁹ The buildings function as ecological traps: the insects are visually lured in by enormous vertical surfaces, then find no food, no host plant, no way to orient themselves. They climb or fly upward, exhaust themselves, and die. If you live in an urban high-rise and have found these insects on upper-story windows or balconies, that behavior is not random. They are responding to the same visual instinct that normally guides them toward tree trunks, just directed at something catastrophically unsuitable.

Broader landscape data supports the idea that urbanization draws SLF in certain ways. One study found that lanternflies appeared earlier in the season in areas with more impervious surface (pavement, concrete) and closer proximity to city centers, likely because urban heat islands accelerate spring warm-up and development.¹⁰ Areas with more canopy cover, by contrast, saw later emergence. So cities do not just trap lanternflies visually; they also create the thermal conditions that speed up their life cycle.

Social Signals and Honeydew

Perhaps the most underappreciated thing lanternflies are attracted to is each other. SLF form large aggregations, and they use a combination of chemical, vibrational, and possibly other signals to recruit more individuals to a gathering spot. Researchers describe this as a multimodal communication system.¹¹ The signals include chemicals released from their bodies, honeydew (the sugary excretion they produce while feeding), and vibrations transmitted through plant stems and bark.

A clever trap experiment demonstrated how powerful these social signals are. When researchers pinned mesh bags containing live-captured SLF to a tree near a trap, the trap captured significantly more fourth instars and adults of both sexes compared with traps near plastic bags (which blocked the signals). The only real difference between mesh and plastic was whether the captured insects’ signals could reach the surroundings.¹¹ This suggests that once a few lanternflies settle on a tree and start feeding, their presence acts as a beacon that draws others in, creating a snowball effect.

Honeydew plays a specific role in sexual signaling. Research on natural pheromone lures found that the dose-response between pheromone concentration and trap captures was significant only when honeydew was also present. Males showed the strongest response during the peak mating weeks, while females responded later, during oviposition (egg-laying) time.¹² In other words, honeydew seems to function as a context cue that makes pheromones meaningful. Without it, the pheromone signal falls flat. This makes biological sense: honeydew on a trunk signals that other lanternflies are actively feeding there, so it is a viable gathering spot for mating.

Why Lures Do Not Always Work in the Field

Given how clearly methyl salicylate attracts SLF in the lab, you might expect baited traps to dominate field management. The reality is messier. In at least one field trial using sticky bands on trees, methyl salicylate lures did not significantly increase captures of nymphs or adults compared with unbaited sticky bands. Total captures were low across all treatments in that study.¹³ Other field tests did find a two- to four-fold increase with methyl salicylate lures, so the discrepancy likely comes down to local conditions: how many SLF were in the area, what competing plant odors were present, trap design, and season.⁴

This inconsistency matters for homeowners and growers considering commercially available traps. A lure that works brilliantly in a low-odor environment might be drowned out in an area thick with tree of heaven and other host plants already pumping out the same chemicals. The multi-component blends that outperformed single-compound lures in lab settings have not yet been fully validated in field deployments, though researchers have identified specific candidates for further testing.⁵ Meanwhile, the trap-enhancement approach of using live-captured SLF as “bait” (in mesh bags pinned near traps) has shown more reliable results in the field, likely because it provides the full suite of chemical, vibrational, and social signals that no single synthetic compound can replicate.

Microclimate Preferences

Temperature and landscape features shape where lanternflies show up in less obvious ways. Although SLF activity peaks during warm months, the Maryland modeling study found that within a given area, lanternflies were more likely to be present in relatively cooler microhabitats.¹ The researchers interpreted this as the insects seeking fine-scale refugia, spots that buffer heat and moisture stress and align with their preferred thermal range during each life stage. Pasture and hay land cover was positively associated with SLF presence, while developed low-intensity land was negatively associated. The presence of sumac, a secondary host plant, and higher human population also contributed to predicting where lanternflies would turn up.

For your yard, this means that shaded, somewhat sheltered areas near known host trees are the likeliest hotspots. A south-facing wall that bakes in the afternoon sun may actually be less attractive to them than a cooler north side with overhanging branches, at least during the height of summer.

How They Spread to New Areas

While lanternflies are attracted to host plants, light, and each other within a given area, the way they colonize new regions is driven overwhelmingly by human activity. Modeling work found that simulations without human-mediated dispersal predicted the observed spread of SLF correctly only about 33% of the time. Adding even modest human transport, as few as three successful hitchhiking events per year, jumped accuracy to 92%.¹⁴ The spread closely follows roads and major highways, which also happen to harbor the highest densities of tree of heaven. This creates a feedback loop: highways carry the insects to new places, and those places already have the host tree growing along the roadside.

Railways play a similar role. In one survey of the northern Ohio Valley, 30 out of 31 SLF captured in 2022 were found at a single site near a railway, consistent with rail-mediated dispersal trends documented across the country.¹⁵ So while the question of what lanternflies are “attracted to” usually focuses on host-finding behavior, the most consequential movement in their invasion is passive. They ride along on cars, trucks, and trains, often as egg masses laid on flat outdoor surfaces, and end up wherever those vehicles stop next.

Shared Grape and Tree of Heaven Chemistry

One reason lanternflies threaten vineyards so directly is that grapes and tree of heaven share key volatile compounds. Chemical analysis found that both grape and tree of heaven produce (E,E)-α-farnesene, which made up about 19% of the volatile profile of grape and about 78% of tree of heaven. Methyl salicylate appeared in both as well, at roughly 4% in grape and 2% in tree of heaven.⁴ From the insect’s perspective, grapes smell partly like tree of heaven. This chemical overlap means that even if tree of heaven were eradicated from an area, the volatile signals coming from a vineyard would still register as attractive. The insect is not “confused” by grapes; it is genuinely responding to the same chemicals that flag its preferred host.

This overlap is also why methyl salicylate lures work as broadly as they do. The compound is not unique to tree of heaven. It is produced by many stressed or damaged plants as a defense signal, meaning lanternflies may be essentially eavesdropping on chemical distress calls across the plant kingdom. For growers of other crops, including hops, stone fruit, and hardwood timber, the implication is clear: if your plants release these common volatiles, they are sending a dinner invitation whether you intend it or not.

A Note on Light Traps and Practical Home Use

The UV and blue-light preference documented in laboratory choice experiments has raised interest in whether light traps could work against SLF. Commercially available bug zappers that use UV light would, in principle, be hitting the right part of the spectrum. However, the research on spectral preference was conducted in controlled arenas, and no large-scale field trials have validated UV trapping as a meaningful population-reduction tool for lanternflies. SLF are daytime feeders and do most of their moving during daylight hours, so a nighttime UV zapper may not catch the bulk of the population when it is most active. Still, many homeowners report anecdotally that lanternflies are drawn to porch lights and illuminated windows at dusk, consistent with the documented UV and blue preference. Using warm-toned, longer-wavelength outdoor lighting (amber or yellow LEDs) could reduce the accidental attraction, though this has not been experimentally tested for SLF specifically.

For people managing lanternflies on their property, the hierarchy of attraction gives some practical guidance. Removing tree of heaven (or treating it with systemic insecticide to use it as a “trap tree”) addresses the strongest single attractant. Reducing competing host plants like sumac limits secondary draws. Traps work best when positioned on or near the hosts the insects are already visiting, and adding live-caught SLF in a mesh pouch near the trap appears to boost captures more reliably than chemical lures alone. The science is evolving, but the insects’ own signals remain the most potent recruitment tool researchers have found so far.

1
Environmental Research Communications. Machine learning reveals host, microclimate, and landscape drivers of spotted lanternfly occurrence in Maryland
2
Environmental Entomology. Distribution, Survival, and Development of Spotted Lanternfly on Host Plants Found in North America
3
PubMed Central. Life history traits of spotted lanternfly (Hemiptera: Fulgoridae) when feeding on grapevines and tree of heaven
4
Journal of Economic Entomology. Discovery of Three Kairomones in Relation to Trap and Lure Development for Spotted Lanternfly (Hemiptera: Fulgoridae)
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Environmental Entomology. Plant Volatiles Help Mediate Host Plant Selection and Attraction of the Spotted Lanternfly (Hemiptera: Fulgoridae): a Generalist With a Preferred Host
6
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9
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12
PubMed Central. Spotted Lanternflies Respond to Natural Pheromone Lures for Mate-Finding and Oviposition
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PubMed Central. Human-mediated dispersal drives the spread of the spotted lanternfly (Lycorma delicatula)
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Journal of Economic Entomology. Evaluating spotted lanternfly (Hemiptera: Fulgoridae) infestation in the Northern Ohio Valley