Turn off the light: artificial light pollution and its effect on insects
Let’s look at the dark side of artificial night lighting.
We've all become accustomed to squeezing in as much time for work and play as we can in a day. Thanks to artificial night lighting, we can now prolong daylight hours, making space for nighttime productivity at the expense of darkness.
This blog will take a closer look at the dark side of light. It will answer a question prompted by the massive expansion of artificial night light: What is the effect of artificial light on nature - specifically on insects - and can light pollution cause insect declines?
Light pollution
Before answering the above question, it’s necessary to unpack the concept of light pollution and explain it. The UN Development Programme talks about light pollution as follows:
"Light pollution refers to artificial light that alters the natural patterns of light and dark in ecosystems. It comprises direct glare, chronically increased illumination and temporary, unexpected fluctuations in lighting. The sources of ecological light pollution include sky glow, illuminated buildings, streetlights, fishing boats, security lights, lights on vehicles, flares on offshore oil platforms, and even lights on undersea research vessels."
Composite image of the Earth at night, 2017 – NASA
The impact of Artificial light at night (ALAN)
Significant declines in several species of insects have been discovered in the UK and Germany. Land use change, pesticide use, climate change, and habitat fragmentation are considered to be the main drivers of these declines. However, according to the authors of Insect declines and agroecosystems: does light pollution matter? Artificial lighting is an often overlooked driver of insect decline.
The study describes the effects of artificial light at night at the organism level but also at the community and population level.
One of the effects of night-time artificial light at the organism level is the attraction of nocturnal insects to the artificial light source. Although this is the most obvious and easily observed effect, its underlying causes are still unclear.
So-called "flight-to-light" behavior directly increases insect mortality, with some insects killed instantly on contact with the lamp and in other numerous cases, death occurs due to exhaustion from constant flying around lamps. In the latter case, insects are unable to leave the vicinity of the light source and migrate elsewhere, causing a decline in insect pollination at the local level.
Artificial lighting does not only act as an ecological trap, it also harms insects by preventing them from communicating, altering their physiology, life traits, and nocturnal habits, including migration, feeding and reproductive behavior.
These are just a few of the negative impacts that artificial light has on insects at night. Scientists agree that the impact of artificial light on insects and other organisms needs to be better studied.
The worldwide consumption of light is growing while the price of lighting is declining. It’s becoming increasingly difficult to watch the starry sky in cities or to simply stay in the dark. How do you perceive light pollution? We’d love to hear your thoughts on the topic in the comments below.
Sources:
- Grubisic, M., van Grunsven, R. H. A., Kyba, C. C. M., Manfrin, A., & Hölker, F. (2018). Insect declines and agroecosystems: does light pollution matter? Annals of Applied Biology, 173(2), 180–189. doi:10.1111/aab.12440
- https://ourworldindata.org/light
- https://leap.unep.org/knowledge/glossary/light-pollution