The spotted lanternfly (SLF), Lycorma delicatula, is an invasive planthopper first detected in the United States in Pennsylvania in 2014. Originating from parts of Southeast Asia, including China and Vietnam, this pest has since spread to numerous states, raising significant concerns due to its broad diet and potential harm to agriculture and natural ecosystems. Many people observing these insects often wonder if lanternflies are drawn to light, a common question regarding their behavior.
The Lanternfly’s World
The spotted lanternfly undergoes a single generation each year, progressing through distinct life stages. Eggs are laid in masses, typically covered with a mud-like coating, on various surfaces from tree trunks to outdoor furniture during the fall. These eggs hatch into nymphs in the spring, which are initially black with white spots, then develop striking red and black coloration with white spots in their later nymphal stages. These wingless nymphs are capable of hopping, while adults, emerging in late summer, possess wings and can undertake short flights.
Spotted lanternflies are sap-feeding insects, utilizing piercing-sucking mouthparts to extract sugary sap from plants. While their preferred host is the invasive tree-of-heaven (Ailanthus altissima), they feed on over 70 plant species, including economically important crops like grapevines, maples, and fruit trees. Their feeding activity results in the excretion of a sticky substance called honeydew, which can promote the growth of black sooty mold on affected plants and surfaces. Spotted lanternflies possess compound eyes and antennae, which they use for navigating their environment, locating host plants, and interacting with others.
Their Attraction to Light
Spotted lanternflies exhibit a behavior known as phototaxis, which is a movement or orientation in response to light. They are attracted to certain types of artificial light. Research suggests that short-wavelength light, such as ultraviolet (UV) and certain blue light frequencies, can be particularly appealing. This attraction to artificial light sources often draws them towards illuminated structures and areas, especially at night.
The reasons behind this attraction are thought to be complex. One theory suggests that artificial lights can disrupt an insect’s natural navigational systems, which often rely on natural light cues like the moon or stars for orientation. Another possibility is that bright lights mimic conditions associated with preferred host plants or aggregation sites, leading lanternflies to congregate around them. The intensity of the light can also play a role, with brighter sources generally exerting a stronger pull. This behavior can vary with the lanternfly’s life stage, with adults often being more visibly drawn to lights.
Light-Based Strategies for Control
Understanding the spotted lanternfly’s attraction to light offers practical avenues for managing their populations. Light traps, for instance, can be utilized as a monitoring tool to detect the presence of lanternflies in an area or to gauge population density. These traps lure and capture insects, which can help reduce local numbers.
For homeowners, awareness of this attraction can inform choices regarding outdoor lighting. While completely eliminating outdoor lights may not be practical, adjusting the type or intensity of lighting can help reduce inadvertent attraction. Additionally, inspecting outdoor items like vehicles, grills, and furniture, especially those near lights, is advisable before moving them to new locations, as lanternflies, including their egg masses, can be found on these surfaces. This practice helps prevent the accidental spread of this invasive species.