COS 37-4
Impact of ecological light pollution on nocturnal Lepidoptera

Tuesday, August 12, 2014: 2:30 PM
302/303, Sacramento Convention Center
Kylee Grenis, Department of Biological Sciences, University of Denver
Shannon M. Murphy, Department of Biological Sciences, University of Denver
Background/Question/Methods

Nearly half of the world’s human population lives in urban areas with artificial night lighting, which degrades night skies. Artificial lights can create ecological traps for species that use the moon as a cue for important behaviors. The number of moth species is rapidly declining due to anthropogenic changes in the environment, but the cause is not readily apparent. Whether light pollution causes an ecological trap for moths and/or causes changes in community structure has not been studied yet and is of critical importance because Lepidoptera provide essential ecosystem services as pollinators and prey. By using artificial lights instead of the moon, individuals often suffer increased predation and limited access to resources. These negative impacts illustrate the potential fitness consequences of streetlight attraction for moths and lead us to posit that artificial light may act as an ecological trap. Over time, the alteration of moth behavior by light pollution may result in differing communities in areas of high and low light pollution. We sampled moth communities in 22 sites surrounded by human development five times in the summers of 2011-2012 to look for community responses to light pollution while controlling for habitat size and vegetation cover. 

Results/Conclusions

We found no relationship between area, vegetation cover, and light pollution, which allowed us to independently test these effects on moth abundance and species richness. Using multiple regression, we found that neither habitat size or vegetation cover affected moth abundance and species richness. Two light pollution measures had contrasting effects; more illuminance led to higher abundance and richness while higher luminance decreased abundance and richness. Additionally, we performed three experiments at both larval and adult life stages to look for mechanisms driving changes in moth communities across this gradient.