Definitive Answer: Why Insects Are Attracted To Light

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Notably, insects seem to only be attracted to artificial light sources. Theories that have flown around include that they are attracted to the heat of the source, or that they confuse the light source with the moon in an attempt to navigate.  But why do insects actually gather by light sources?

The problem researchers have had in studying the attraction of insects to light is simple: bugs fly really fast. In low-light conditions, this has made their movements hard to track, with everything instead appearing blurry.

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In Dr Fabian’s study, published by Nature Communications, motion-sensitive cameras were set up under both controlled conditions (in a lab) and outdoors (in backyards and the Costa Rican wilderness).

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Insects don't fly towards light but follow a natural response called dorsal-light-response (DLR), which helps them maintain a steady angle to the light source, like the moon, for orientation.

So, Why Are Insects Attracted To Light?

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In other words – gravity affects flying insects less than it does us, so they naturally face their back towards the light of the moon to keep oriented.

Image by Samuel Fabian

Insects may circle artificial light for a near suicidal length of time, depleting their energy reserves and increasing their vulnerability to predators. Moreover, if the light source comes from below, insects will flip upside down and subsequently crash into the floor.


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Insect populations are declining, with recent studies showing a 20–75% decrease in numbers and diversity across various groups and ecosystems over the last few decades.

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Further research is necessary to determine whether there are wavelengths that affect insects’ innate DLR less than others. Interestingly, there are species of nocturnal insects that don’t seem to be attracted to light at all; this too warrants further study.

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Future Studies

Definitive Answer: Why Insects Are Attracted To Light

Image via Depositphotos