Environmental Impacts

Survival of fireflies in urban communities is threatened by many factors.

  1. Pesticides and chemicals in lawns:  Indiscriminate use of insecticides can kill many insects that are not the intended pests to be controlled by the insecticides. This includes fireflies. Adult fireflies can be killed by insecticides that are sprayed directly on them or when they get in contact with insecticide residue on the grass or leaves. One step in conserving firefly is to limit the use of insecticides during the time of firefly activity.

  2. Pollution - water, soil, light:  Pollution of water and soil, which the fireflies depend on for survival, can kill fireflies. The sources of pollution include chemical (pesticides, fertilizer, detergents, orther chemicals) and biological pollutants. Light can also be a source of pollution. Strong, bright light can outshine the flashing and interfere with the behavior of fireflies.

  3. Land use pattern and habitat changes:  Changes in land use pattern alter the native habitat of fireflies. Fireflies preferred wet and shading areas to lay eggs, rest and develop. Development of forested areas into open lawns or residential gardens can dry out suitable habitats and reduce the habitat of fireflies.

  4. Forest management:  Forest management practices, such as harvesting, winter burning or brush clearing, can significantly change the structure of the canopy and the physical properties of the environment, thus reducing the habitats of fireflies.

  5. Drought and other environmental changes:  Drought and other significant weather events can change the conditions of a firefly habitat.

Firefly as Ecosystem Indicators – Environmental indicator is used to communicate information about ecosystems and the impacts of human activity to groups such as the public or government policy makers.  The indicator can reflect a variety of aspects of ecosystems, including biological, chemical, and physical characteristics.  The researchers at Clemson University are studying firefly as environmental indicator for the coastal South Carolina. The unique bioluminescence property of fireflies provide visual clues of environmental quality and are easy to measure and quantify by the general public.

Fireflies are charismatic and reliable indicators of environmental health because their population density is correlated to the availability of healthy habitats (Kazama et al., 2009). A good firefly habitat is one that is moist, contains large amounts of natural organic matter (Wu and Perng, 2007). The habitat of fireflies is significantly impacted by urban development. For example, converting forested areas into open lawns, residential gardens, and agricultural field can change the structure of suitable habitats (Kazama et al., 2009; Juson et al., 2010). Indiscriminate use of insecticides in lawns and urban areas can kill many non-target insects, including fireflies. Pollution from commonly used chemicals (e.g., pesticides and fertilizer) and biological pollutants (e.g., pet waste) could also alter the quality of the habitat (Lee et al., 2008; Leong et al., 2007). Light can also be a source of pollution (Viviani et al., 2010). Strong, bright light can outshine firefly flashing and interfere with its mating behavior. All these factors work in concert to reduce the quantity and quality of habitat, thus reducing the density of fireflies. Therefore, the occurrence of firefly provides a visual clue on the quality of the natural environments. 

Kazama et al. 2007. Ecological Modeling 209: 392-400.
Wu and Perng 2007. Formosan Entomologist 27: 31-45.
Jusoh et al. 2010. Wetlands Ecology and Management 18: 367-373.
Viviani et al. 2010. Biota Neotropica 10” 103-116.