Ever wonder why light makes insects tick?

Discovery Place Nature


If you've seen the movie A Bug’s Life, you might remember the scene when the bug flies straight towards the light in a trance-like state. You might also think about your own experiences during the summer and the insects flying around your porch light. Some insects are attracted to light but others are not.

The term phototaxis describes how an organism responds to light with motion. This interaction can be positive or negative and insects can display both types of phototactic behavior.

Insects like moths, beetles and stink bugs have positive phototaxis are attracted to light. Other insects like cockroaches have negative phototaxis and are repelled by light.

There are many theories as to why insects behave this way. One theory is that insects use the light of the moon as a navigational tool and artificial light, such as porch or street lights, may confuse their normal behavior. Another theory is that insects, like moths, move towards lighted areas to avoid predation.

Lights that emit high levels of ultraviolet radiation have been shown to attract the most positive phototactic insects. Many farmers use artificial light traps that emit UV light to control pest species near their crops.

Prefer to keep bugs away? Try a yellow bug light – many insects have trouble seeing light with a lower color temperature – or simply turn off any light you’re not using.