Why are Bugs Attracted to the Light?


It might sound like one of those old facts that everybody knows, but you’d be surprised to hear that there is a science behind why bugs are attracted to the light.

It’s a cruel trick of nature, when you think about it, isn’t it? Nature’s bugs are attracted to contained light, which is an entirely man – made concept. Because of this, it actually makes it easier than ever before for us to attract them, in order to get rid of them.

Not so great for the bugs, but incredibly useful for us!

If you have a porch light, and you turn it on in the evening once the sun has set, then you’ll notice that suddenly you’re likely to have a bunch of visiting creepy crawlies. From moths, to regular flies, to beetles – you’ll see that all forms of pests love to follow the light.

As we mentioned, it can be extremely useful in preventing them, using devices such as the electric bug zapper, and rather damning for the poor creatures themselves.

So, why are bugs attracted to artificial light? Is there a science behind it?

Read on to find out more!



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Why are Bugs Attracted to the Light?

What is the Science Behind Bugs Being Attracted to Artificial Light?

All of this begs the question, is there a science – or at least a reason – behind why bugs are attracted to artificial light?

Let us take a look, shall we.

  • Unfortunately for many of these insects, we have moved quicker in our development of technology than they can follow.
  • Many of the night – time insects are literally guided by the moonlight. They can’t see without it, and this is how they navigate their way around.
  • Given that we’ve now introduced artificial light into the environment, many of these insects now, quite literally, think it’s the moon guiding their way. It’s kind of sad for them when you think about it. Their capacity of knowledge does not allow them to decipher the difference between what is a healthy, natural light for them to follow, and what is man – made and potentially harmful.
  • But it’s great for us if they’re causing us problems. Whereas fly sprays can be difficult to use and manoeuvre because of how quick and nimble flies are, bug zappers, as previously mentioned, can help to eliminate your problem with minimal effort.
  • The science behind bugs using the moon for guidance, is that it provides their reflected light at a particular angle, in order for them to maintain a flight path that’s steady.
  • Artificial lighting therefore makes it more difficult for the bugs to follow it effectively, by obscuring the effect the natural moonlight has. This is because the artificial lightbulb appears as being brighter, and their light spans in several different directions.
  • In doing this, the insect finds it far more difficult to find their way and travel in the right direction, and will automatically navigate in regards to the light bulb, rather than by the natural light of the moon.
  • Because of the artificial light radiating in several different directions, the insect in question cannot keep the light at a certain angle. Which means that they’re likely to fly directly towards the light. Which could result in them being sucked into an insect trap without even realising it…

Good for us. Not so good for them.

This Begs the Question, is the Abundance of Artificial Light Killing the World’s Instincts?

In some species of insect, it could be believe that the abundance of artificial light in the world is therefore putting them in danger of becoming extinct.

  • In some cases – let’s use a moth as an example – the life span of these insects are small to say the least.
  • Therefore, if a moth spends the vast majority of it’s short life circling the overhead light in your bathroom rather than reproducing, does this put the species of moths at danger of becoming extinct altogether?
  • These kinds of species rely entirely on energy which is built up during the larvae cycle in their life. Therefore wasting it on circling the same light over and over rather than what they would do in the entirely natural world must put their species in danger, surely.
  • In some cases, there are rows of artificial lights – for example street lamps and similar – which will restrict the movement of insects in certain areas.
  • There is another impact of artificial lighting on bugs and their cycle, which is referred to by professionals as the “vacuum cleaner affect”. This refers to flies and insects that are lured away from their natural habitats by artificial lighting.
  • A prime example of this, would be mayflies. These spend the initial stages of their lives in water, and then later produce their wings and mate. Their lifespans are ultimately short, which means that if these are wasted circling artificial light rather than reproducing, their species could become extinct.
  • In these circumstances, many mayflies will actually end up stuck along highways and in streets, where there are a row or an abundance of artificial light.
  • They will come in swarms, some of the time, and fly along these highways and places crowded with light. Unfortunately, often, they’ll then end up depositing their eggs along the roadside, rather than giving birth to them in their natural habitat.
  • It’s likely that after this, they will die.

Which Kinds of Artificial Lighting are Likely to have the Largest Effect on Insects?

Before we finish off, we’re going to be taking a break from looking at how artificial lights affect insects. Instead, we’re going to be having a look at what kind of artificial lighting is likely to have the most impact and effect on insects.

  • The first of these, is without doubt, Mercury Vapour Lights. These are great if you want to catch night – time flying insects, and are often used by scientists who study them, as well as entomologists. They capture and study them using this variety of lights.
  • However, in many cases, the average street lamp will use Mercury Vapour Lights. This isn’t as good news for the insects in question, as it’s likely to have the negative impacts on them that we listed above previously.
  • It’s also rather unpleasant for those who live in a street filled with lamps using these kinds of light. We know it’s nature taking its’ course, and really its our own fault, but nobody wants an infestation of flies in their street, do they?
  • Another kind of light which has proven to be confusing for the insects that “go fly in the night” is the incandescent bulbs. Another of which, is compact fluorescent bulbs. Unfortunately, many common outdoor lights used for both security and décor in gardens use these kinds of bulbs.
  • If you’re having issues with insects in your garden or outdoor space, particularly on an evening however, there are certain things that you can to do prevent the encouragement of them.
  • Warm colour LED bulbs are a great alternative, as they aren’t as bright, and therefore the insects will not be as directly attracted to them.
  • There are actually yellow bulbs available online and in homeware stores, which are marketed with the sole purpose of not attracting insects. Sure, they might not be as bright, but who doesn’t like a little bit of mood lighting, anyway?

Overview

Before we go today, we’re going to be giving an overview of how and why bugs are attracted to artificial light.

  • The reason why most bugs are attracted to artificial light, is because they’ll usually use the moon to navigate them on an evening, and are therefore confused by it.
  • However, the light is different, and because lightbulbs radiate in all directions and these insects need to hold this light at a specific angle in order to navigate correctly, they then become confused, and often end up hovering around overhead lights, for example, in porches.
  • This can have a direct impact on the particular species of the insect, two of which that we listed above, are the moth and the mayfly.
  • This is because of their short lifespans, particularly. If they are attracted to the light and therefore spend much of their short lives circling and following it, then they aren’t going to get the chance to properly develop in their habitat, and ultimately reproduce and keep the species going.
  • There are different lights that have varying degrees of impact on these insects. For example, an incandescent bulb will ultimately attract more flies and insects to it, than if you were to go for a warm LED bulb.
  • If you’re having issues with repelling light – encouraged insects, then there are some kinds of warm yellow lighting which are advertised specifically for keeping the insects away from your home, porch, or wherever you’re having the issue.

Thanks for reading today. We hope we have helped you to better understand the reasons behind why certain bugs are attracted to light, how it’s impacting them, and what you can to prevent this issue affecting you.

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