Why are bugs attracted to light?

+74 votes
asked May 15, 2015 in Science by Collin (1,370 points)
I just turn on the porch light and it is as though every species of flying insect decides to swarm it. Is it the warmth? Are they just freaky mesmerized? What is the reason bugs are attracted to light?

2 Answers

+23 votes
answered May 24, 2015 by carlee (1,170 points)

Not all bugs are attracted to artificial light, for example, the butterflies and even cockroaches won't do this. The ones that are, however, seem to be so because of confusion. Bugs being attracted to artificial lights are actually following a normal instinct called phototaxis.

In ages past, there were only natural lights (stars, moon, and sun). Nocturnal bugs were guided by the stars and moon while bugs that thrive during the day rely on sunlight to see. When a light goes on outside, these bugs get confused and usually swarm to the light for guidance to find food. For some bugs, the artificial light is too bright and throws their natural instincts off. These bugs just dive straight for the artificial light (these would be the bugs you see, and hear, constantly slam themselves into the bulb or around it). Some bugs that are usually moving about during the day may think that the light means it is day light.

+10 votes
answered May 16, 2015 by B (1,060 points)

Why are bugs attracted to light? Actually, there are many theories as to why bugs like the light.

  • They may think it is daylight and be confused.
  • Night flying bugs may think it is moonlight and be confused.
  • UV light attract some bugs so these bugs may be attracted to the UV rays.
  • The heat from the light might attract bugs.
  • The light may confuse certain bugs by making them think another bug is wanting to mate. For instance, fireflies use their lights in mating rituals.

You may get more information from the reference link.

REFERENCE:  http://www.wisegeek.org/why-are-insects-attracted-to-light.htm

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