Have you ever woken up in the middle of the night to satisfy midnight cravings and as you turned the kitchen light on, you saw some tiny insects scurrying away? Those were very likely cockroaches. These are mostly nocturnal creatures that come out in the night to forage for food and water.
Roaches have existed since time immemorial and with evolution, these insects have become one of the most resilient creatures in the world. Scientists believe that the most likely survivors of a nuclear explosion are going to be cockroaches.
One of the reasons for this strong survival instinct is their being nocturnal. Most of their natural predators like humans and land animals are asleep at night.
But sometimes we spot cockroaches during the daytime as well. So, this begs the question if cockroaches are nocturnal or diurnal creatures. And if they are indeed nocturnal then why so.
Are Cockroaches Nocturnal or Diurnal?
If we generalize, then cockroaches are indeed nocturnal creatures. They are most active at night when we are in deep sleep.
This is an adaptation the cockroaches developed after years of survival as they are quite tiny. Imagine if we see cockroaches roaming about during the day. There is no way we will not try to kill them off.
This is the sole reason why roaches prefer the dark over the light. Moist, warm, and dark conditions are ideal for these pests and that is why they make their nests in places like the insides of unused appliances, behind stacks of paper, inside shoe racks, in sewers and drains, etc.
Cockroaches thrive better at night and even have better control over their movement and senses in the dark.
Researchers at The Department of Entomology at the National Taiwan University conducted experimental research on the German cockroach in which the functions of The Pigment Dispersing Factor (PDF) were studied and it was found that PDF significantly influences the nightly activity in cockroaches.
All of these being stated, it should also remember that cockroaches can indeed also be active during the day.
Some species of cockroaches are diurnal such as Mitchell’s Diurnal Cockroach and the Australian Cockroach but these bugs are very different in their behaviorism from the most commonly spotted varieties such as the Oriental Cockroach and the German Cockroach.
If you do however, spot these common varieties during the day then chances are there will be just one or two and they may have come out of their hiding place due to some external threat.
You will hardly ever spot a swarm of cockroaches feasting on food crumbs during the day because they are nocturnal creatures.
Are Cockroaches Most Active at Night?
Yes, cockroaches are most active at night. Due to multiple factors, roaches prefer to emerge during the night instead of the day. This is both a survival skill as well as an adaptation. Rather than saying, they are active at night, it would be appropriate to say that they prefer the absence of light.
But this does not mean that cockroaches are completely immobile during the day. Other than appearing out of their hiding place if they detect an external threat to their life, cockroaches may also have to scavenge for food during the day. Due to being cold-blooded, they can survive multiple days without any food.
And if a cockroach is unable to forage for any food during the night with all the cockroaches in the colony also actively scurrying about for the same reason, it may come out during the day.
When the infestation reaches a severe state, the time no longer matters because no matter what time of the day, you will also see cockroaches. In such a state these insects may even get daring enough to bite humans as they sleep.
However, in cases of mild infestations the cockroaches who come out during the day will mostly do so at dawn or dusk when human activity is still limited.
Why are Cockroaches Only Active at Night?
The cockroach is a nocturnal insect because of its circadian rhythm. Just as the human circadian rhythm makes us active during the day and automatically feel sleepy during the night, in cockroaches too the same thing happens but in an opposite manner.
Roaches are adapted for feeding, mating, and gathering in the dark because there are several advantages to it:
Most of the natural predators of cockroaches are diurnal, that is they are active during the day and rest at night. These include mammals, birds, turtles, and reptiles. It is a survival mechanism that has been adapted by the cockroaches. They just know that during the night, these threats will not be present making the time safer.
Nighttime is Quieter
Cockroaches are equipped with organs that give them a 360-degree spatial awareness to a certain distance. In simpler terms, even without facing a particular way, they will know if a threat is getting closer to them.
This is why it is assumed that cockroaches are easily scared which is indeed true to a certain extent. Cockroaches can determine the size and distance of predators through super-sensitive organs on their posterior end. In the dark, there is no such threat and thus cockroaches can carry about their tasks in peace.
An act like mating or reproducing is important to carry on the line. It makes sense for cockroaches to want to mate in safety and to also store their eggs in a safe and secure place.
Due to the peace and safety that the dark brings, cockroaches will prefer mating at night. But if they do even mate during the date, it is improbable that you will spot a cockroach roaming about with an egg sack when it is still light.
Female cockroaches give much importance to the preservation of the egg sacks which are either attached to the bottom of their body or deposited and kept in a safe spot.
Feeding Pattern Matches Circadian Rhythm
Finding food is easier at night because as the humans are asleep, there is nobody to intervene.
On top of that, their circadian rhythm matches their feeding pattern thus making it ideal for them to hunt for food during the night.
Do Cockroaches Sleep During the Day?
Yes, cockroaches sleep or rest during the day. They choose dark, warm and moist place to rest. This is also why cockroaches usually build their nests in the back of appliances such as CPUs and Refrigerators because they can get some warmth from there.
In a 1986 experiment, cockroaches were kept active and simulated during the daytime or their period of rest. It was found that before they start their activity at night, it is usually preceded and followed by a period of rest. This is not like humans who enter an unconscious state but rather a period of immobility.
This groundbreaking study conducted by Irene Tobler inspired much further research on insect sleeping patterns and each of them more or less emphasized the importance of this period of rest that insects including cockroaches go through.
If not allowed to rest, cockroaches will exhibit similar behavior to sleep-deprived humans. In simple words, cockroaches do rest during the day and if they don’t, it might affect their metabolism and mortality.
Sleep Behavior of Roaches
Cockroach sleep behavior has three distinct circadian stages:
- Active or Locomotion Stage: The activity stage or wake stage. This is usually when the cockroaches are at their most active. Usually a few hours after sundown between 10 pm to 12 am.
- Limb and Antenneal Movement Stage: Think of this as similar to when we humans just start to fall asleep or just start to wake up. Cockroaches in this stage are immobile but still make minor movements in their limbs and antenna. Roaches are in this stage usually in the early evening or late morning.
- Deep Sleep Stage: In this stage, cockroaches are completely immobile and do not even flinch or make any minor movements. They are usually in this stage during the day.
Cockroaches go through cycles of these three stages to stay alive and healthy.
Are Roaches Scared of Light?
No cockroaches are not afraid of light and neither are they harmed by it. But it is a common misconception to assume that cockroaches fear light as they are always seen to hurry away whenever we turn on lights.
But if you think carefully, almost all animals react like this to a sudden burst of light after staying in the dark for some time. Even humans. But since for us there is no danger associated with light, we simply cover our eyes and get adjusted to the light for a while.
But for cockroaches, the sudden presence of light can also mean the appearance of predators, which is the very reason why they hurriedly scamper away.
How Long Do Cockroaches Sleep?
Unlike humans, cockroaches do not need a full eight hours of continuous sleep at night. However, it is still assumed that they do get around 8-10 hours of rest in installments within 24 hours.
The exact time for each stage of their circadian rhythms depends on predator activity and the intensity of light but their most deep stage of sleep where they go completely immobile takes up multiple hours in their sleep cycles.
Therefore, cockroaches can be termed as nocturnal creatures that are active during the night and go through a period of rest during the day.
Their sleeping stages are very essential for their metabolism and nervous stability and a rest-deprived cockroach may even die.
So, if you are trying to eliminate cockroaches using insecticides then do so during the day when they are in their most deep sleep. This is when they are at their most vulnerable and are unlikely to run away when attacked.