Are Fleas Attracted to Light or Heat? Here Is The Answer

Are fleas attracted to light or heat? Well, both light and heat attract fleas for the most. Those factors attract fleas more than others such as air currents, movement, host odor, gravity, physical contact, warmth, carbon dioxide, and etc. It sounds surprising, right? Now, let us focus on the light and the heat.

Here, both light and heat attract fleas during the period where they look for the host. As soon as the fleas come out from the cocoon, they must look for some meal to prevent starvation. Within a week, they must find a host and feed themselves. This is the most critical period for them to survive.

Those stimuli, light, and heat, are the cues for fleas in finding the host. It is well known that fleas can immediately jump after they come out from the cocoon to attach a host. However, in this case, the other stimuli are needed to reinforce the accuracy in detection.

Now, let us discuss more the light and the heat in the following passages.

Are Fleas Attracted to Light?

are fleas attracted to light or heat
Are fleas attracted to light or heat?

So, we all know that some insects fly around the lamp at night. This is a normal phenomenon that happens on a daily basis. But, what about fleas? We all do know that fleas are active during day and night but it doesn’t have any wings to fly around the lamp.

In this case, are fleas attracted to light? The answer is yes, fleas do attract to light. But, it doesn’t mean that fleas will suddenly jump to the lamp like other insects that fly around it. Here, fleas have their own way of responding to the light. There are some reasons why are fleas attracted to the light. Well, let us start with Phototaxis.


So, what is phototaxis? Phototaxis is a kind of ability to respond to light by moving directly to the source that organisms have. This ability does not only exist on the insects but also on the plants. For example, you may realize that a sprout that you hide in a dark place will always grow directly to the source of the light. It is just like you grow a sprout in a box with a small hole, and within a few days, you find that all the buds pointing out to the hole.

While, on the other side, insects will perform the same when they fly or move directly to the lamp at night. The clearest occasion to catch this moment is that when you see how some small moths flying around the lamp. Then, the other clearest case comes from flying termites. You can find like hundreds of flying termites gather around a lamp.

Now, what about fleas?

If you expect that fleas will suddenly come in large troops together in a light source, it will not happen. In this case, fleas are attracted light but they have a different movement toward the light. Here, studies found that adult fleas, which are actually newcomers from the cocoon, are attracted to the light. Precisely, there is a study found that 93% of fleas in a dark place will move to the brighter one within 40 minutes.

Then, on the other side, studies find that new adult fleas will climb to higher objects in natural settings. It is also normal to find fleas on the top of the grass, waiting for potential hosts before jumping to them. But, related to this particular case, do fleas always jump? No, they do not always jump.

The Light Color Fleas Attract to

When it comes to the color of the light, there are some colors that fleas are attracted to. The color of the light that fleas are attracted to is a green-yellow colored light. That color has the 500-530 nanometers of wavelengths. Thus, there is no wonder that flea traps use a green-yellow filter because it surely works.

While on the other side, the other colors seem not that attractive for fleas. It is observed that colors such as blue and green attract similarly to standard light which attracts less than a green-yellow colored light. Well, do not use this color to trap the fleas then. Just pick the right one.

In addition, the other colors such as magenta, red, medium blue, and yellow attract completely lower than the standard light. So, it means that you have to avoid those colors when you choose the flea traps. Just pick the right one which is the green-yellow colored light.

The Intermittent Light Attracts Fleas More

I believe we all do know that fleas will jump and follow the hosts they meet. But, I also do believe that actually, it is related to the light, intermittent light precisely. So, how does intermittent light attracts fleas?

A study found that fleas are attracted to light and the attractions rise when there is an interruption. It is like you see a light from the lamp for about 10 minutes and then sees a shadow for 5 seconds. There, the shadow attracts more than the light.

In this case, the attraction is similar to the way how the potential host walks passing by and interrupt what fleas watch. Instinctively, fleas will jump and follow that distraction. It is just like a decoy when you want to lead the prey walking to the trap. Well, the problem here is that the fleas cannot differentiate it.

That’s why fleas trap with intermittent light works better than the one that uses continuous light. It is also found that trap flea with intermittent light works 5 times better. So, it can be concluded that you need a green-yellow colored light trap with intermittent light. Also, it is clear that fleas are attracted to light.

Now, let’s move to the heat.

Are Fleas Attracted to Heat? 

It is a normal thing that any creature will find their way to adjust their body heat. Some of them will use materials covering their body and the others will just simply go to the heat source. For example, in the cold season, your pets will love to sit near the fireplace and humans will cover themselves with a thick blanket or jacket. Those activities are done to adjust the body heat.

While on the other side, you can find that in summer, people would wear short pants, and thin clothes to stay cool. They will stay away from any heat sources in the noon because that will be so hot. Cats, if you observe, they will stretch their body while sleeping when the temperature is getting hotter. In that situation, the cat will stay away from fire and do not cuddle with each other.

So, what about insects, especially fleas? Let’s start with thermotaxis first.


Well, let us understand the terms thermotaxis first. In a short definition, thermotaxis means the response of organisms to the heat; it can move toward or go away from the heat source. In other definition, thermotaxis means the movement based on the gradient of the temperature. So, both definitions emphasize that organisms do respond to the heat.

So, what about fleas?

Well, it is found that fleas movement belongs to the positive thermotaxis that means fleas will move toward the heat source. This movement is also known as thermophilic behavior that does exist in other organisms. The heat that shows in fleas’ radar helps them to identify the host since that is only alive creatures that can provide the blood meals.

As an alive creature, the body will produce heat that is detected in fleas’ sensory organs. So, heat can help them to distinguish the difference between the dead and alive objects. In this case, fleas use their antennae to detect the heat.

Wait…Do fleas have antennae? Yes, fleas do have antennae.

It may surprise people at first because antennae in insects usually long and even can be as long as the body. But, in fleas, you will find a different type of antennae. These antennae only can be seen with a microscope because the size is so microscopics. It is even smaller than the fleas’ eyes.

The antennae in fleas are located behind their eyes. It is just like very small curves hair with highly sensitive response. These antennae have very great sensory functions in detecting humidity, vibration, touch, smell, and of course heat. So, no wonder it helps fleas in looking for potential hosts.

Now, let us discuss more the topic.

What Temperature Attract Fleas?

Actually, fleas do not have any particular temperature preferences. It is observed in some studies that they attract to a warmer temperature. However,  the 104°F (40°C) temperature attracts them for the most. On the other side, it is also observed that fleas are attracted to 122°F (50°C) temperature. So, it means that fleas can attach to any hosts as long as the host is a match for them.

Well, surprisingly, those temperatures are in the range of both human and pets body temperature. So, I think that is the reason why fleas attracted to heat on that temperature. Or, is it already their instinct to follow the human and pet temperature? No one knows what comes first. But, that is a very logical reason why fleas consider pets and humans as their potential hosts.

Heat Indicates The Potential Host

Why do fleas attract to heat or even body heat? It is a good question because the fleas do not heat to warm their body. It is true that they are attracted to the heat, but the purpose is not to adjust the body heat. In this case, the body heat is one of the indicators, the minor one, that indicates what they sense is their potential host.

As has been mentioned before, human and pet body heat is similar to the temperature degree that attracts fleas the most. So, looking for alive hosts means that fleas will not pick the body temperature that has a very big gap with their preferences. It also the logical reason why fleas can go away anytime when the host is going to be cold because of its death.

This information may surprise you, but here is what I want to share.

Fleas are known to leave their host once the host is dying and going to be cold. It is so surprising because we sometimes think that fleas only look for blood. Actually, a dead body can also provide some fresh flood in very few minutes. But, on this occasion, fleas, especially the adult, will leave them and move to the others.

In this case, they will jump and move to the warmer one near them. Well, it possibly happens when the fleas move from the prey to the predators while they are in contact. Or, the setting can be a nest or burrow where sometimes one of the family dies but the others still live near them.

Heat + Pressure Trigger The Fleas Cocoon

The other surprising thing from heat attraction to fleas is that warmer temperature plus pressure will make fleas go out from their cocoon. So, it means that when your pets sit on their cocoon, then the new fleas will immediately emerge. It seems like they do know how to locate their host easily and efficiently.

Then, on the other side, without any warmth, the cocoon will enter to the dormancy mode. It is a condition where organisms prefer to stay and it is similar to hibernate. But, in the case of fleas, they will stay in their cocoon for about 5 months. Well, no wonder it is hard for us to completely get rid of fleas because they can survive in a long period.

Well, the other interesting thing is that the fleas cocoon can be attracted to the warmth of human breath. But, at the same time, they are not attracted to the heat trap that only uses heat. So, do not use a trap that only uses heat to lure and catch the fleas. Considering to add their most favorite color and light in the fleas trap.

In short, are fleas attracted to light or heat? Yes, fleas are attracted to the light and the heat since those two factors help them to indicate the potential host. The combination of the light and the heat completely help fleas to indicate and locate their potential host. Do not underestimate this.

Tips in Using Heat Lamp Flea Trap

To use a heat lamp flea trap more effectively, there are some important tips to do as follows:

  1. Choose the flea trap with yellow light color and heater features.
  2. Keeping some flea traps in different rooms. If you have a limited budget, you can surely move this trap from one room to another. But, if you have an extra budget, buying a few traps for each of your rooms can ensure all will be well.
  3. Put the trap in your washroom close to the door. If you groom your own pets in your washroom, there is a possibility that the egg fleas spread there which soon are going to hatch and become adult fleas. Or, sometimes, your pet visits you there. So, that is a reason why you have fleas in your washroom.
  4. It works best at night. In the night, make sure that the only light source you have in your room comes from the trap. So, the fleas will surely jump to get there.

Well, actually, it is quite rare to find a well-designed heat lamp trap specifically for fleas. So, I cannot make a huge list for now but, surely I will add later if I find the others. However, if you are wondering is there any heat lamp flea trap with the combination of light and heat, I actually find that one.

Get Happy Jack Flea Beacon Trap Now
Are Fleas Attracted to Light or Heat? Here Is The Answer

At the glance, this flea trap may look flimsy and fragile. But, later on, you will find that it works well. This flea trap not only has a yellow light color but also the heat that is generated from the light bulb installed in the trap that attracts fleas more.

Here, I find that people are so happy with this heat lamp flea trap because it is so affordable, removes fleas with no harmful pesticides, and captures a number fleas only in a few days.

So, that is all I can share about the fleas attraction to heat and light. Well, do you want to share something or have any suggestions? please feel free to write it down below. Thank you 🙂