Light pollution is the brightening of the night sky with artificial light beyond what is essential for safety and navigation. Insects are essential for functioning ecosystems. Artificial lights attract insects, thereby disrupting their natural behaviors and negatively impacting urban and suburban environments. These behavioral disruptions have severe consequences for insect diversity (Degen et al. 2024, Owens et al. 2020). In fact, light pollution is emerging as a major contributor to the decline of insects in many parts of the world, in addition to more obvious factors such as habitat loss and overuse of pesticides. Light pollution also negatively impacts bird migration patterns and impacts human health by disrupting normal circadian rhythms essential to healthy sleep patterns (Burt et al. 2023, Falchi et al. 2011).

Insects’ attraction to light sources is a well-known phenomenon that has eluded understanding until recently. Experiments using 3D video data have suggested a deceptively simple explanation. As a navigation tool, nocturnal insects orient their bodies with their top (dorsal) side towards the light, whether it is faint sky glow at night or a point source such as a porch light (Fabian et al. 2024).

Insects being lured to light sources is not the only problem caused by light pollution that negatively impacts insect diversity. Fireflies are beetles in the family Lampyridae. They are fascinating and familiar members of the insect community in appropriate habitats in Louisiana, most of North America, and globally. Many people have happy memories of catching fireflies as children, and firefly tourism has risen dramatically in areas where healthy populations remain. Firefly populations have suffered severe population declines in many areas of Louisiana and elsewhere. Concerned citizens and dedicated firefly preservation organizations, such as the Xerces Society, have sprung up to identify and mitigate the causes of firefly decline (Lewis et al. 2021).

Most species of fireflies possess organs that produce light because of a chemical reaction involving an energy rich molecule, luciferin, and an enzyme, luciferase. This reaction produces distinctive greenish or bluish flashes or sustained glows of fireflies. Adults of many fireflies utilize species-specific flash patterns to identify prospective mates, and one group of fireflies even mimics the flash patterns of other fireflies, then kills and eats them when they mistakenly approach. Despite the bright flashes against a dark landscape that are familiar to most people, the light produced by fireflies is relatively dim, and artificial lights such as porch and streetlights render communication among individual fireflies impossible. In light-polluted environments, no mating occurs, and thus the population can disappear in a single generation. Other factors that contribute to firefly decline include removal of moist leaf litter and decaying wood habitats required by the predatory firefly larvae, and the potential non-target impacts of insecticides such as mosquito fogging in areas of adult activity and broadcast soil insecticide treatments where larvae occur. Reestablishing adult and larval habitats are necessary steps for firefly recovery, but in areas of excessive lighting, fireflies are unlikely to return and thrive.

Light pollution also creates problems for homeowners and businesses by attracting large numbers of insects that are normally dispersed across the landscape. Many residents of Louisiana anticipate with anxiety the annual clouds of Formosan subterranean termites (Coptotermes formosanus) that fly around streetlights, typically around Mother’s Day, which coincides with the peak mating swarms of the year for the species. These flights normally originate in areas where woody debris accumulates such as wooded corridors along bayous, nearby forests, infested trees and discarded lumber. In these areas, termite mating flights pose little threat to homes or other wood frame structures and serve as a valuable food source for insect-eating wildlife such as birds and frogs. Streetlights attract the termites into neighborhoods, where porch lights and illuminated windows subsequently attract them to homes. Inevitably, a few find their way into homes where they are a nuisance and, if moisture issues and other suitable conditions for termite establishment are present, they may potentially create colonies and cause major property damage. Turning off lights at night can help supplement professional preventative termite management and home moisture maintenance to help protect structures from Formosan subterranean termite damage.

Other nuisance problems occur when massive flights of midges (members of the family Chironomidae, order Diptera) emerge from their aquatic habitats and converge on well-lit neighborhoods and businesses. A secondary problem is the attraction of frogs, toads and nocturnal lizards (e.g., geckos) to abundant insect food supplies around residential lights, where they deposit fecal material and lure snakes that feed on them. Moths attracted to porch lights often lay eggs on adjacent surfaces, resulting in large numbers of wandering caterpillars, some of which are potentially turf or garden pests. Less common, but potentially costly problems include mass flights of sugarcane beetles (Euetheola humilis), which are strongly attracted to lights on and around buildings. Upon arrival, the adult beetles may burrow into the weather seals around windows, causing leaks and requiring expensive repairs. Different cockroach species, such as the smoky brown cockroach (Periplaneta fulginosa) are attracted to lights and may enter structures and forage for food. Other unexpected, normally day-active insects, are attracted to light, such as certain species of dragonflies and many other species of small insects. Spiders may establish webs near lights to prey on plentiful insects that accumulate nearby. Other organisms, such as bats and nocturnal insect-feeding birds (e.g., night hawks and screech owls), are deterred by excess lighting, and therefore do not consume pest insects and rodents in well-lit locations. Some light-attracted insects may even pose a threat to human health. Kissing bugs (Triatoma spp.) are blood-feeding insects that are potential vectors of Chagas disease in Louisiana. Kissing bugs are rarely encountered since the native species spend most of their life cycle in the vicinity of wild hosts away from homes. However, adult kissing bugs disperse during certain times of the year, are strongly attracted to artificial lights and are thus lured to houses where they may enter at access points near lights.

Light pollution continues to rise nearly unabated around the world and has recently increased because of the transition to highly luminous energy efficient light emitting diodes (LEDs) (Pothukuchi 2024). Common shorter wavelength LEDs in the blue end of the visible spectrum strain human eyes, have been shown to be lethal to nocturnal insects and disturb other wildlife due to their higher sensitivity to shorter wavelengths (Owens et al. 2024). Blue wavelengths also increase the glare of light on surfaces and produce more intense sky glow than longer wavelengths. Artificial lighting is a complex and often divisive social issue due to the perception that more nighttime lighting increases security and contributes to crime prevention, but evidence is lacking that supports this claim (MacDonald et al. 2026).

Citizen-led Initiatives

Small, incremental steps can reduce light pollution, substantially improve habitats and reduce light trespass that impacts nearby residents. Local neighborhood initiatives increase public awareness and promote efforts to convert local security lighting to less polluting but equally effective types of fixtures. Bright, undirected (i.e., no cutoff), high mounted fixtures such as streetlights mounted on telephone poles should be eliminated and replaced with lower, downward directed fixtures using longer wavelength light sources that are orange or red in color. Individual residential security lights can be replaced with motion sensitive lights calibrated for large animals or intruders. Many residential developments are implementing less invasive security lights and integrating outdoor lighting restrictions into homeowner association covenants. Shutters are available that can diffuse light so that it is less harmful to wildlife but still provide visibility to residents. Warm spectrum lights are preferred, with red being the least harmful. Indoor lighting should be turned off at night, or the windows can be shuttered if light shines outdoors. For a full explanation of the benefits of dark sky friendly lighting, see the information provided by the organization Dark Sky International.

Establishing “firefly sanctuaries” in local parks and other green spaces can improve habitat for many nocturnal animals in addition to fireflies. Many organisms benefit from dark wildlife corridors in addition to having access to their preferred habitats. Consideration should be given to dark wildlife corridors along undeveloped waterways and forests to allow migration into sanctuaries and reestablish diminished populations. At larger scales, active lobbying of legislators, local politicians, urban planners and utility companies can emphasize the growing demand for environmentally responsible public lighting. Individual citizens can become involved in these efforts. Another effective approach is to join one or more of the many social, scientific and environmental organizations that are leading organized efforts to mitigate light pollution. Astronomy organizations are among the most active and motivated groups lobbying for positive change in public lighting because it directly impacts celestial observations. Many of these organizations have dedicated light pollution committees that monitor lighting patterns and encourage best practices to reduce the impacts of light pollution.

Traveling to a designated dark sky site can lead to greater appreciation of the beauty of an unpolluted night sky and is an excellent way to get people young and old motivated to become activists in reducing urban and suburban light pollution. Field trips offered by churches or scouting groups and summer youth camps provide opportunities to visit dark sky sites. These venues are often located in dark sky locations. Most residents of brightly lit towns and cities have never seen the Milky Way (the galaxy in which we live) arcing brightly overhead on clear nights. Observing the Milky Way is possible under dark skies during most months of the year from most locations on Earth. Reducing light pollution benefits society, human quality of life and the environment in a multitude of ways, however, to prevent it requires education and activism to change the way public lighting is used and perceived.

Online Resources

Baton Rouge Astronomical Society

Bortle scale, a method of visually assessing dark sky quality

National Geographic Education, Light Pollution

Pontchartrain Astronomy Society

Rewilding Institute, The Ecological and Human Need for Dark Skies

Shreveport Bossier Astronomical Society

The Xerces Society for Invertebrate Conservation

References

Burt, C.S., J.F. Kelly, G.E. Trankina, C.L. Silva, A. Khalighifar, H.C. Jenkins-Smith, A.S. Fox, K.M. Fristrup, K.G. Horton. 2023. The effects of light pollution on migratory animal behavior. Trends in Ecology and Evolution 38: 355-368.

Carlton, C., F. Huval and T. Reagan. 2019. Triatoma sanguisuga, Eastern Blood-Sucking Conenose Bug (Hemiptera: Reduviidae). LSU AgCenter Publication 3694. 2 pp.

Degen J., M. Storms, C.B. Lee, A. Jechow, A.L. Stöckl, F. Hölker, A. Jakhar, T. Walter, S. Walter, O. Mitesser, T. Hovestadt, T. Degen T. 2024. Shedding light with harmonic radar: unveiling the hidden impacts of streetlights on moth flight behavior. Proceedings of the National Academy of Sciences U S A. 15: 121: 2401215121. doi: 10.1073/pnas.2401215121. Epub 2024 Oct 8. PMID: 39378094; PMCID: PMC11494349.

Fabian, S.T., Y. Sondhi, P.E. Allen, P.E., J.C. Theobald, and H.-T. Lin. 2024. Why flying insects gather at artificial light insects gather at artificial light. Nature Communications 15: 689.

Falchi, F., P. Cinzano, C.D. Elvidge, D.M. Keith, and A. Haim. 2011. Limiting the impact of light pollution on human health, environment and stellar visibility, Journal of Environmental Management 92: 2714–2722.

Lewis, S.M., A. Thancharoen, C.H. Wong. 2021. Firefly tourism: Advancing a global phenomenon toward a brighter future. Conservation Science and Practice

MacDonald, J.M., A. Chalfin, M. Moritz, B. Wade, A.K. Mendlein, A.A. Braga, and E. South. 2026. Can enhanced street lighting improve public safety at scale? Criminology and Public Policy 25: 31–62.

Owens, A.C.S., P. Cochard, J. Durrant, J.B. Farnworth, E.K. Perkin, B. Seymoure. 2020. Light pollution is a driver of insect declines. Biological Conservation 241: 108259.

Owens, A.C.S., M.J. Pocock, and B.M. Seymoure. 2024. Current evidence in support of insect-friendly lighting practices. Current Opinion in Insect Science 66: 101276.

Pothukuchi, K. 2025. Mitigating urban light pollution: A review of municipal regulations and implications for planners. Journal of Urban Affairs 47: 1663–1690.

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Fireflies (Coleoptera: Lampyridae) flashing in a lupine meadow in Maine. Photo by Mike Lewinsky, Creative Commons 2.0

Time exposure photo of the Milky Way over the Peloncillo Mountains in southern New Mexico. Such images are possible only under dark, unpolluted skies. Photo by Chris Carlton

A dragonfly fluttering around a porch light in Baton Rouge, Louisiana, is an example of a normally day-active insect lured to artificial light. Photo by Aaron Ashbrook