Image 1: This image depicts a close-up of a moth in flight. Image courtesy of PickPik.
Springtime brings an influx of moths that appear to mindlessly flutter into porch lights and street lamps. Many may associate moths colliding into these lights with a lack of intelligence. However, one study conducted in Costa Rican forests revealed that moths are not to blame for flying into artificial lights.
In the study, researchers captured high-resolution videos and high-speed infrared recordings of the flight trajectories of moths near artificial light. The results demonstrated that at closer distances, moths do not intend to directly fly into light sources. Rather, moths turn their backs toward the light at a right angle, causing them to invert their flight or orbit, even when this action increases their potential of crashing. During the daytime, tilting their backs towards natural light allows moths to maintain a proper trajectory. However, artificial sources of light lead the insects to continuously turn their backs to the light, trapping them in a cycle that causes constant and unstable fluttering.
While these changes in flight patterns seem harmless, artificial lights cause major concerns for moth populations. For instance, these lights may greatly disrupt moths’ sleeping and eating patterns by signaling daytime. In addition, light pollution causes these insects to become more visible and thus more vulnerable to predation, possibly contributing to a decline in their population. Understanding how we affect the behavior of these little creatures can help us create an environment that limits unnecessary stress, allowing them to keep fluttering around every spring.