Date of Award
Shannon M. Murphy, Ph.D.
Light pollution, Species interactions, Nocturnal lepidopteran communities
Over half of the world's population lives in urban areas leading to night skies that are substantially degraded by artificial lights. Yet, we know little about how light pollution affects the surrounding natural communities. What we do know focuses on the impact of light pollution on individual species. Therefore, I investigated the impact of light pollution on species interactions. I determined whether light pollution is a mechanism of community change, evaluated whether there were changes in species interactions between predators and prey, and indirect and direct interactions between insect herbivores and their host plants by examining the entire life cycle of nocturnal Lepidoptera (moths). Ultimately, I found that light pollution induces an ecological trap for moths.
I evaluated the importance of light pollution in structuring moth communities by collecting moths from a wide variety of prairie fragments with different habitat sizes, vegetation, and light pollution levels to determine if there are any changes in abundance, richness, and composition of the lepidopteran community in response to these variables. I found that light pollution changes the abundance, richness, and composition of moth communities. Notably, my research indicates that direct sources of light pollution, such as streetlights, may have different consequences on nocturnal lepidopteran communities than night skies degraded from indirect "skyglow".
To determine potential mechanisms underlying these patterns and whether or not light pollution acts as an ecological trap, I also completed two projects to test the fitness costs of light pollution on moths at the larval stage. I found that nocturnal generalist predators do not forage preferentially for larvae in streetlit or unlit areas along suburban prairie fragments. However, light pollution induces direct consequences for larvae and indirect negative effects on larvae mediated through changes to host plant quality induced by light pollution.
My research determined that more moths and species are attracted to sites with high levels of light pollution. I also determined that there are negative consequences at the larval stage to living in illuminated areas that are mediated through species interactions. Therefore, light pollution creates an ecological trap for moths.
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Grenis, Kylee, "Impact of Light Pollution on Species Interactions" (2016). Electronic Theses and Dissertations. 1140.
Received from ProQuest