Which Flies Are Attracted to Light?
WouterScientists have discovered that some species of flies are attracted to light at specific wavelengths. Among these species, wild-type Drosophila are most attracted to green (565 nm) and blue wavelengths. Mutants that lack the UV-sensitive R7 and blue-sensitive Rh5 cells prefer green light. The attractiveness of these wavelength bands varies throughout the day, and appears to be circadianly regulated. Despite the fact that they prefer different wavelengths throughout the day, mutant flies show an increased attraction to blue and UV light, and a decreased sensitivity to green light (595 nm).
Other insects that are attracted to light sources include mosquitoes and cockroaches. Light is an excellent source of food for many insects. Many moths feed on nectar, which reflects ultraviolet light. Some light bulbs also give off a small amount of ultraviolet light. Because of this, hungry bugs may mistake light sources for flowers. Light also tells insects where to go if they are in danger. Insects are often attracted to lights because they need the warmth.
While flies that live in the dark don’t necessarily need light to survive, most insects do. They can’t distinguish between natural and artificial light. They will continually circle a light source even if it is not a real light source.
