Cockroaches are no one’s favourite idea of a house guest. If they are in your home chances are that you want to know why they are attracted to your home and how to get rid of them. A common belief is that cockroaches and other bugs such as spiders and centipedes are attracted to our homes by the bright lights.
We investigate this popular belief to find out if LED lights attract cockroaches and if there are ways we can light our rooms without encouraging the unwanted guests!
The short answer is yes. LED lights attract cockroaches just like any light source, such as incandescent or fluorescent bulbs. However, it is not the light source itself that attracts the roaches, instead, they are drawn towards the other bugs and insects that are attracted to the light.
The reason why LED lights attract cockroaches is that insects tend to be attracted to light sources. As a result, the insects will congregate around any available light source at night and this attracts cockroaches and spiders that are looking to feed on the insects.
Do LED Lights Attract Cockroaches?
As we have seen above, it turns out that cockroaches are attracted to LEDs but in a rather roundabout way; they are attracted to the bugs being drawn towards the light and heat emitted by the LEDs. However, LED lights produce less heat than traditional bulbs so they don’t typically attract as many bugs and insects. This low heat has the added benefit of making the LED bulbs blow less often than traditional light bulbs.
As you might expect, several other factors can influence whether or not certain pests are attracted to lights. For example, if your home is dark and dirty, it will naturally attract more pests than a clean and well-lit home.
Therefore, how attracted cockroaches and bugs are to your lights depends on a few things:
1. The wavelength of the light
2. Where do the insects live, ie on the ground or in the trees?
3. How much light there is. A flashlight might attract some insects, but a fire would attract more because it gives more light.
4. What kind of insect is it? Many insects are nocturnal, so they sleep during the day and are awake at night, and many of them use the moon or stars to navigate by flying toward the light source. Others like fireflies can produce their own light used to attract mates (fireflies) or prey (angler fish).
Most insects, in general, are attracted to light and will fly toward any bright light, even a flashlight. This in turn brings the cockroaches (and also the centipedes) who are hungry and looking to feed on the bugs.
Do Lights Keep Cockroaches Away?
So if cockroaches aren’t directly attracted to the light source is there a way we can use light as a weapon to keep cockroaches away?
Cockroaches can live in any environment, no matter how well lit. Light can be a repellent, as it makes them feel nervous and exposed, but it’s not enough to stop them from entering your home in search of food. Once inside your home, they will go where the food is and not be kept away by the light.
Cockroaches choose to hide in dark areas during the day to be less noticeable and more protected from predators. In a study by Szymanski, J. S published in the Journal of Animal Behavior, Szymanski “attempted to change the direction of movement of male cockroach larvae (1-1.5 yrs old), Periplaneta Orientalis L, from dark to light areas by the punishment method.”
It showed that when faced with a punishment the cockroach will head towards the light source as it doesn’t cause them any direct harm.
So it turns out, lights don’t kill cockroaches, as many people hope. But if you have a large infestation of roaches in your home, it may be useful to use lights to lure them out of hiding spots during the day so that you can effectively kill them.
Since most of us are asleep at night and don’t use our kitchens as much, we don’t notice the roaches until it’s too late!
On the flip side, according to Matt Bertone, there’s no evidence lighting up your house prevents cockroaches from coming inside in the first place. The only thing it could potentially help with is keeping you from accidentally stepping on one of these creepy creatures when you walk into your garage or porch after sundown.
Do Lights Repel Cockroaches?
It seems there is some conflicting evidence regarding whether or not cockroaches can be repelled by lights.
Overall it appears that most cockroaches will show some level of aversion to light. Studies have shown that certain cockroach species, such as the American cockroach, Periplaneta americana (L.), and the German cockroach, Blattella germanica (L.), are most likely to be repelled by light.
It appears that certain wavelengths of light repel cockroaches. However, this is somewhat species-specific. Specific wavelengths will repel German cockroaches while having little effect on American cockroaches; however, other wavelengths repel American cockroaches but have little effect on German cockroaches.
This study entitled, “The effect of illumination with different light wavelengths on the orientation of Turkestan cockroach” (linked here) discusses in detail an experiment testing how different light wavelengths affected cockroaches’ behaviour.
In general, German roaches tend to avoid light and prefer darkness. Therefore, you can use this to your advantage when eliminating them from your home.
If you place traps in areas that are well lit throughout the night, they may not go near them at all. However, if you turn off the lights in an area where you’ve seen roach activity and place traps there instead, you’re more likely to catch them with the lures.
What Colour Light Do Cockroaches Hate?
As referenced in the study linked above it appears that:
When it comes to the colour of light that cockroaches hate, red light is the most effective colour for repelling cockroaches but other colours including green and blue light also work well. However, it is not the intensity of these colours that repels the roaches but rather the wavelengths associated with each.
Cockroaches do not see ultraviolet light and cannot detect UV rays far away because they have weak eyesight. However, by using the wavelengths of coloured lights it appears we have another weapon in our arsenal to repel the cockroach!
How To Get Rid of Cockroaches?
Light is not a major factor for cockroaches deciding where to live so we may be better served looking at other ways to get rid of cockroaches.
Overall we have learnt that cockroaches will not be deterred by light so much as they will be attracted to it (due to the other insects drawn towards the light). Cockroaches are nocturnal, which means they are most active at night and prefer darkness over bright lights during the day.
This makes them susceptible to light pollution, and you may find them in areas with high levels of artificial lighting, such as parking lots and streetlights trying to catch their next meal.
That being said, if you want to avoid attracting cockroaches into your home, try turning off any lights at night that may be near food sources or places where roaches could hide, such as under sinks or behind appliances.
When you see a cockroach in your home, it is usually because there is a food source nearby or a place they can hide, turning on the light won’t have that much of an effect on them.
Light or dark, if there’s food and water (and a nice hiding spot), they’ll come. That said, some things do make roaches more likely to stick around. The most important is a lack of ventilation: they like airy, moist places that are also cool but not cold.
They also like dirty places, so this tip is essential: clean up after yourself! Don’t leave dirty dishes sitting out; wash them as soon as you eat. Make sure your trash is covered and emptied frequently – don’t let it sit around and don’t leave food out on the counter!
Some people have had luck with pest control traps, though these aren’t foolproof and obviously won’t solve the root issue of why you have roaches in the first place. With any luck, though, these suggestions will help you get rid of them!
Do Led lights attract cockroaches? The short answer: Yes–but it won’t make a difference. Cockroaches are scattered in every lit-up city or dark alley and LED lights are not the biggest factor that attracts cockroaches.
Cockroaches seem to be more strongly attracted to other things in your house, so focus more on ridding your home of these pests’ food sources and dirty resting areas to eliminate the problem of unwanted cockroaches!