Insects improve our lives – they are an important part of the food chain and pollinate the plants we use for food and the ambience in the garden. But humans make this work difficult, also because the artificial light we use changes the normal behavior of insects.
New research from UCLA and the Smithsonian Conservation Biology Institute shows how the type of light people use can make a huge difference in even one of the most flawed places on earth – the Amazon Basin. The study, published March 16 in Insect Conservation and Diversity, shows that a certain type of light minimizes human effects on natural systems.
The study also reveals important findings for human health and wellbeing. Artificial light attracts biting insects and other annoying or harmful species that can spread deadly diseases. The type of light people use can help keep people safe, according to research.
One of the co-authors of the study is UCLA conservation scientist Travis Longcore, whose previous research looked at what lighting, in theory, would most and least disturb insects. The Amazon Basin, where the Peruvian government is planning an energy infrastructure project in an area that has never been exposed to artificial light, provided the perfect opportunity to test its predictions.
“The question we wanted to answer is, ‘If you need to set these things on fire, how should you do it to minimize the impact on the environment? “Said Longcore.
The paper found that LED light, filtered to be a yellow or amber color, attracts fewer flying insects, which are essential to the health of the local environment – and that blue and ultraviolet light are more harmful because attract them so much more.
When light is needed for maintenance workers or other purposes, the trick is to use yellow and amber and use the least amount of light possible. While other types of lights are somewhat more effective at minimizing insect attraction, research has focused on LEDs as they are the most commonly used. LEDs tend to be more energy efficient and effective than other light sources.
Jessica Deichmann, a Smithsonian conservation biologist, led the team of US and Peruvian researchers into the jungle to conduct the study. (For those traveling from the United States, the trip from Washington, DC, to the test site in Peru took five days, two plane flights, and three boat trips.) The project was nearly abandoned when special batteries did not arrive on time. But a delivery man on a motorcycle got the batteries there on the last possible day before the researcher’s boat was supposed to leave.
On site, the researchers lived in a small tent city under a larger tent structure to protect them from heavy rain. They installed various arrays of LED lights and collected the insects that appeared, and sorted, identified, and counted the insects.
“Our results were almost exactly in line with the predictions made by Travis Longcore’s earlier work,” said Deichmann, the study’s lead author. In previous studies by Longcore, an optimal light spectrum range was determined for as many insects as possible at the same time.
The results also confirm that it is fairly easy for a business or new community to reduce the impact of their lighting on insects and biodiversity. Just choose lamps that are least likely to attract not only insects but other wildlife as well. Lighting can be chosen so that it is less harmful to the natural behavior of sea turtles, frogs and other species that are exposed to artificial light at night.
Several studies in recent years have warned of the decline in insect populations and biodiversity. As more infrastructure encroaches on natural ecosystems, UCLA-Smithsonian research shows a way to minimize human impact on them. Dimmer lights are better, and it is best if the lights can be turned off at night. If a place needs to be lit at night, it is better to work with amber light than white light.
If lights attract insects that transmit disease or cause the death of thousands of insects that pollinate food crops, human communities will pay a high price, Deichmann said.
The results are also relevant well beyond the Amazon – and even beyond wildlife habitats in general.
“Changing your lights is something you can do right on your porch,” said Deichmann.
“Or you can take steps to make sure that the lights in your neighborhood have as little impact on nature as possible.”
For example, insect zappers emit light that attracts insects, but they are inefficient at killing species such as mosquitos. They tend to kill mostly beneficial insects as they move pests closer.
For Longcore, the results showed a relatively basic message for anyone choosing to illuminate their homes and businesses.
“Don’t get the cold light LEDs and place them all over your property,” he said, referring to colors like blue and purple. “Individual decisions add up.”
