Artificial light at night (ALAN) is a major contributor to the global decline in insects. In an article published today in Insect Conservation and Diversity, scientists and partners at the Smithsonian Conservation Biology Institute (SCBI) found that using amber filters to remove the blue light spectra from “warm white” LED lamps (light emitting diodes) dramatically reduces the attraction of insects night lighting in a tropical forest. This is the first study to validate quantitative predictions of how lamp color will affect insect attraction and provide clear recommendations for mitigating the negative effects of ALAN on wildlife in rainforest ecosystems.
“While many people don’t necessarily like ‘bugs’, their importance in our daily lives is undeniable,” said Jessica Deichmann, lead author and research scientist at the Smithsonian Conservation Biology Institute and the Smithsonian Conservation Commons’ Working Land and Seascapes Initiative. “The essential ecosystem services they provide are threatened by night lighting. We shouldn’t avoid the use of LED lights – their energy efficiency is second to none. Our research offers an alternative, especially for outdoor environments. When people everywhere take small steps in our environment We can reduce the negative impact of sustainable LED lighting on wildlife in homes, neighborhoods and commercial properties. “
In addition to using filtered LEDs which remove the blue light and appear more orange / amber, insects can also be assisted by the use of full shutdown devices, motion activators and dimmers to ensure that the light is only used when and where it is needed .
Insects play an invaluable role as pollinators of food crops, regulators of other insect pests, decomposers of waste and sources of food for other animals such as birds. Insects can be directly affected by lights if they die from collisions with hot lamps, exhaustion, or increased predators due to predator attraction and / or increased visibility. Insects affected by artificial light can also become disoriented or inactive, resulting in poor reproduction and, consequently, a decrease in gene flow in the population.
The study was carried out in the lowland rainforest in northern Peru under a hydrocarbon (oil and gas) concession currently operated by GeoPark Peru. Scientists place light traps in 12 different locations with three different LED lamps with different spectra and a control (no light) to assess the number and composition of insects that are attracted to lamps during two different periods of time during the night.
The researchers identified 763 unique morpho species among the more than 15,000 insects caught in all samples, belonging to 18 different orders. Overall, significantly more morpho species were detected in the white LED light traps than in the yellow or amber-filtered traps or in the control. Likewise, significantly more individual insects were caught in the white LED traps.
By using amber-filtered LEDs, the number of morpho species attracted by the light was reduced by 34% and individual insects by almost 60% compared to white LED lamps with a reduced blue light content. In addition, among the captured insect families known to contain important vectors of pathogens, bacteria or parasites, 45% of all individuals were found on white lamps, 41% on yellow lamps and only 13% on amber lamp traps.
These results provide critical, tangible, and actionable information for minimizing ALAN, an inevitable consequence of many types of infrastructure development and urbanization. The paper contains specific management recommendations for new infrastructure projects in tropical forests that can also be applied to urban and rural residential areas.
The other co-authors of the paper are Christian Ampudia Gatty, National University of the Peruvian Amazon, Faculty of Life Sciences; Juan Manuel Andia Navarro, La Molina National Agricultural University, Klaus Raven Büller Museum of Entomology; Alfonso Alonso, SCBI; Reynaldo Linares-Palomino, SCBI; and Travis Longcore, UCLA Institute for the Environment and Sustainability.