We have all heard the phrase “like a moth to a flame” used to describe the irresistible attraction between two people. At first, we might think this is very romantic, but let’s dive a little deeper. A moth… flying directly into a burning flame? Sounds like a toxic relationship to me! In reality, it very much is. Artificial light at night is causing moth declines in cities, but luckily, there may be some solutions.
Many nocturnal moths demonstrate flight-to-light behaviour, which means they have an irresistible impulse to gather around light sources like streetlights in cities. However, there are many downsides to this behaviour. When flying around light, moths lose valuable energy and are more likely to be eaten by predators. This is bad for the moth, of course, but also for the rest of us. Moths play an important role in city ecosystems because they are pollinators and prey sources for many different urban plants and critters! So, to keep a balanced ecosystem, we must come up with solutions to protect our city moths!
Dr. Tanja Straka is an urban ecologist and researcher who focuses on nocturnal biodiversity and human-nature interactions in urban areas. In her research paper, she explained that urban moths have a very important role to play in building more sustainable and biodiverse cities.
A study was led by Dr. Straka at Technical University Berlin in Germany to find out how three different urban landscape variables would affect city moths: light pollution (streetlights), tree
cover (tree shade in cities), and impervious surfaces (parking lots or roads). Urban landscapes are “dynamic ecosystems where human design intersects with nature and by rethinking how we illuminate our cities and integrating more natural elements like tree cover, we can create urban environments that support biodiversity rather than disrupt it,” said Mt. A urban planning professor Dr. Corrine Cash. Previous studies have only looked at these three variables separately, but never all together, allowing this new study to really shed some light on the problem!
Dr. Straka and her team chose 22 different study sites in Berlin, where they identified and counted 442 moths in total! After analyzing their data, they came up with two main conclusions. The researchers discovered that streetlights negatively affected moth richness, which is how many different moth species there are, while areas with impervious surfaces negatively affected moth abundance, which is how many of each species there are. The second thing they discovered was that if an area had more tree cover, it would have both higher moth richness and abundance. The locations where streetlights had the most negative effects on moths were areas with impervious surfaces and low tree cover. Let’s just say moths are probably not huge fans of the ‘parking lot.’
The results of their research provide us with some solutions to help our city moths! Firstly, making sure to save dark areas in city environments is important, and where this is not possible, replacing streetlight bulbs with alternatives that moths do not love as much or that are motion activated. Secondly, plant more trees in cities! Having green spaces in cities supports moth richness and abundance. “Biodiversity within these urban green spaces is important in creating habitats for native species,” said Kyla Wilkinson, an environmental studies major at Mt. A.
Overall, this study has shown us that maybe the phrase “like a moth to a flame” is not all that romantic… maybe it should be “like a moth to a tree”! This relationship seems a bit healthier, don’t you think?
