Question: Why did the moth visit the psychiatrist’s office?
Answer: The porch light was on.
Attraction of insects to porch lights can create a buzz of annoying flying insects and an unsightly pile of dead ones. To reduce the nuisance, homeowners will invest in bug lights, bulbs that are less attractive to insects but produce a ghastly yellow light. Is there a high tech alternative?
LED technology allows light bulbs to be created with novel features. Light intensity, wavelength and flickering can be tightly controlled. Humans have a “critical fusion frequency” (CFF) of around 60 Hz. A light that flickers at a frequency of less than 60 Hz clearly flickers. However, a light that flickers at a rate faster than 60 Hz will appear the same as a light that is constantly on. This affect is caused by the speed that our brain processes light.
Insects have a much higher CFF rate than people. The honey bee CFF is around 240 Hz. If a light is flickering at a rate between 60 Hz and 240 Hz, insects see a flickering light but humans see a steady light. LED lights flickering in this range attract fewer insects.* These experimental results may be the basis of the next generation bug lights.
*A Barroso, I Haifig, V Janei, I da Silva, C Dietrich and AM Costa-Leonardo P. Effects of flickering light on the attraction of nocturnal insects. Lighting Res. Technol. 2015; 0: 1–11