The Spotted Lanternfly, Lycorma delicatula, is an invasive planthopper native to Asia that poses a significant threat to U.S. agriculture and native hardwood trees. It feeds voraciously on the sap of over 70 plant species, often weakening or killing economically important crops like grapevines. Understanding what attracts the Spotted Lanternfly is crucial for developing targeted management strategies, as its behavior is driven by chemical, visual, and environmental cues, not just specific plants.
Recognizing the Spotted Lanternfly
The life cycle of the Spotted Lanternfly involves a distinct metamorphosis, with each stage presenting a different appearance. The overwintering stage is an egg mass, laid in the fall on nearly any flat surface and covered by a grayish, mud-like coating. These masses hatch into nymphs in the spring, which are initially black with bright white spots and are incapable of flight.
Nymphs progress through several developmental stages, or instars. The first three instars are black and white, but the fourth and final instar, appearing in mid-summer, becomes brightly colored with a red body, black stripes, and white spots. The adult form emerges around July, measuring about an inch long. Adults have gray forewings covered in black spots, but their striking red hindwings are only visible when the insect is startled or in flight.
Primary Plant Hosts
The primary mechanism attracting the Spotted Lanternfly is the search for phloem sap, the sugary fluid that transports nutrients within a plant. The pest uses specialized, piercing-sucking mouthparts to extract this sap, which provides necessary nutrition. The insect’s preference changes depending on its life stage and the availability of specific hosts.
The most significant attractant is the invasive Tree of Heaven, Ailanthus altissima, which serves as a preferred host, especially for late-stage nymphs and adults. Adults often aggregate on this tree to feed heavily and begin mating. The presence of Tree of Heaven frequently indicates a nearby Lanternfly population.
The insect also feeds on numerous secondary hosts, including fruit trees like apple and plum, and hardwoods such as maple and black walnut. Early-instar nymphs favor the soft tissues of herbaceous plants and tender new growth. As they mature, they shift their attention to the woody parts of the stem and trunk, which offer a richer source of sap for reproductive adults.
Non-Botanical Attractors
Beyond plant tissue, the Spotted Lanternfly is drawn by environmental and chemical signals. One prominent cue is the smell of fermented sap, which weeps from the wounds the insects create while feeding. This fermentation suggests a readily accessible, highly concentrated sugar source, signaling a prime feeding location to other individuals.
The insect produces and is attracted to its own chemical signals, specifically a complex pheromone blend. Research indicates that the combination of volatiles from the insect’s body and the sugary excrement it produces, called “honeydew,” acts synergistically to attract both sexes. This signal is effective at drawing males seeking mates and females looking for suitable egg-laying sites.
Visually, the insect exhibits a strong attraction to tall, vertical silhouettes, such as telephone poles, large tree trunks, and the sides of buildings. This visual cue guides their dispersal and aggregation behavior. The insects also respond to certain low-frequency vibrations, such as the 60-hertz frequency associated with electrical power lines, which may be an environmental attractant guiding their movement.
Utilizing Attraction for Pest Management
Knowledge of the Spotted Lanternfly’s specific attractants is actively used to develop pest management strategies. Due to the pest’s strong preference for Tree of Heaven, this invasive tree is utilized in a “trap tree” approach. Property owners selectively remove most Tree of Heaven on their land, but intentionally leave a few male trees to lure the insects.
These remaining trap trees are then treated with a systemic insecticide, which the feeding insects ingest, effectively reducing the local population. Trapping methods also capitalize on the insect’s tendency to walk up and down tree trunks, which is thought to be a form of thermoregulation. Simple devices like sticky bands and inverted funnel-style circle traps are placed around the trunk to capture moving nymphs and adults.
The identified pheromone blend is leading to the development of synthetic lures for monitoring traps, aiding in early detection and population assessment. The attraction to vertical objects is also used by researchers who monitor utility poles for signs of infestation, as the insects are likely to land on these structures during their dispersal flights. These targeted applications provide a focused and efficient way to manage this invasive species.