In this post, I will cover numerous questions about the humble cockroach. While almost universally hated worldwide, you can not deny these pesky insects are fascinating in their own right.
Do Cockroaches Have Brains?
Yes, cockroaches have brains – but these are basic and simple compared to human brains.
They only have about 20,000 brain cells (compared to the 100 billion humans), and they do not have any pain receptors.
The cockroach’s brain is in its head, and it has a pair of ganglia in the thorax near the nerve cord that helps it process some of its information.
Do Cockroaches Have Nerves?
They have nerve cells – cockroaches do not have very much of them, though, so compared to humans, they don’t feel pain as much as we do.
Cockroaches have two major ganglia, also called nerve cords. One is located in their head, and the other is near their body’s tail end.
These help them control movement, but they don’t give them any sensory information – it’s more like they are “connected” to different parts of the roach’s body, which helps them control movement.
Do Cockroaches Have Feelings?
It is not clear whether or not cockroaches can feel pain. You could assume they do according to their behaviour, but it is difficult to tell for sure due to a lack of research.
Do Cockroaches Have Hearts?
They do not have hearts, but they do have a very long dorsal vessel that carries hemolymph throughout their body. This is more like a system of arteries and veins than anything else, though – no one part can be said to be functioning as a heart.
Do Cockroaches Have Eyes?
Their compound eyes comprise hundreds of lenses (called ommatidia), each with a specific task. They can see fine details this way.
A downside is that they also see everything from many different perspectives, making it difficult to recognize what they’re actually looking at.
Do Cockroaches See?
Cockroaches do not have eyelids and can’t blink. One reason they die in contact with insecticides is that the chemical gets into their eyes and kills them.
They also can’t see colours, but the spectrum of light that they perceive (which has more blue than red) makes it easy for them to distinguish between dark and light.
Can Roaches See in the Dark?
They can see much better in the dark than we can. Their eyes are multi-faceted; each lens has around 150 lenses to help them detect as much light as possible.
They also have many genes devoted to helping them see in the dark.
Do Cockroaches Smell?
They do not have noses as we do, but they still manage to smell and communicate with each other through pheromones (chemicals used for communication).
Additionally, roaches can smell in stereo. Each antenna on their body has around 50 smaller antennas which help them detect different smells.
Do Cockroaches Have Mouths?
Yes, they do. They are located on the underside of their body and open up in a straight line from where their head is to the end of the abdomen.
This might make it seem like they are taking food in through that opening, but this is incorrect. The mouth of the cockroach is called a “proboscis”, and it does not always stay in that straight line.
When they eat, the first thing that goes into their mouth is saliva, which further breaks down food. They are very picky about what they will eat, though – for example, if there are two similar types of food on the floor (same type of leaf, for example), they will choose the fresher one over the older one.
Do Cockroaches Have Tongues?
No, they do not. However, they do produce a liquid that is similar to saliva, and it moistens the mouthparts that are called palps. These palps help them eat food by breaking it down further with enzymes.
Do Cockroaches Have Ears?
Their ears are tiny holes on the side of their bodies. The way they hear is similar to how moths do, although cockroaches have far more hearing organs than moths.
Cockroaches have groups of cells for hearing called chordotonal organs, and they’re located in the joints between their body parts.
They can sense vibrations in the air, the ground and even their bodies. For example, they can hear their footsteps.
Do Cockroaches Have Hair?
They don’t have any hair on their bodies. They are almost completely smooth. However, they produce a waxy compound that coats the body and makes them feel smooth/silky. It also helps them keep moisture in their body (like sweat does for us).
However, some types of roaches have hairs/bristles around/behind their head and on the lower abdomen. These bristles are sensory organs.
Do Cockroaches Have Lungs?
They do not breathe but absorb oxygen through spiracles in their body walls. They also use this breathing method to scent pheromones and release carbon dioxide (similar to humans). This is why you rarely see them panting as dogs do – they don’t need to.
Are Cockroaches Omnivores?
They are not picky eaters. They will eat pretty much anything that smells good.
Their favourite foods are sugars and starches (e.g. fruits, bread).
They can also feed on plant leaves, glue, hair/fur/feathers/skin particles, etc. They will not eat wood, and some roaches can’t feed on leaves because they have been genetically modified to be unable to digest cellulose.
Cellulose is a carbohydrate found in plant cell walls. Humans have enzymes that break down these carbohydrates so we can get energy from them, but cockroaches do not.
Do Cockroaches Carry Diseases?
They do not carry any diseases- they spread them.
Some of the most common infections that roaches can transmit are E.coli (short for Escherichia coli), salmonella, shigella and streptococcus (the last two cause strep throat).
They carry these viruses on their legs, bodies, and intestines.
If you touch a cockroach, its droppings can get under your fingernails. If you eat soon after that, the bacteria from those droppings can also end up inside your body. However, it is not very common for people to catch these infections from roaches.
One good thing to remember is that roaches clean themselves as cats do (they lick their legs and such) – this means the droppings on their legs will not be there for long.
Do Cockroaches Sleep?
Cockroaches do sleep but don’t have eyelids, so they can’t close their eyes. They will only rest in a dark place where they feel safe, and even then, it might be just for a few minutes or hours.
When the roach is resting, its body goes into “stop” mode, meaning all of its muscles will relax (this doesn’t mean they are unconscious, though).
Do Cockroaches Have Blood?
Yes, they do have blood – it is called hemolymph, and it’s closer to an insect’s blood than our blood (the colour varies depending on what type of food they eat).
When a roach loses a leg, it can bleed because the hemolymph will ooze out. Sometimes they will “bleed” to death this way simply because their immune system isn’t strong enough, and other times it might be caused by a bacterium that enters the wound and releases toxins.
Do Cockroaches Have Bones?
They do not have a skeleton – instead, their bodies are made up of a hard protective shell called an exoskeleton. This surface can be hard or soft depending on what kind of species it is – the harder species will have a shield-like shell, while the softer ones will have a smoother one.
They do not need bones because their exoskeleton can support themselves, and their muscles are enough to keep their bodies from collapsing.
Do Cockroaches Shed?
Yes, they do shed their skin when they grow too big for it. They will eat their shed skin after doing this, though, because the new skin underneath is soft and moist, allowing them to move around much easier.
When moulting, they will be very vulnerable to other predators because they cannot move while their new exoskeleton forms.
Can Roaches Survive a Fire?
Yes, they can. This is because their bodies are covered in a wax-like substance that protects them from extreme temperatures (this wax also helps them retain moisture).
This doesn’t mean that they will not suffer great physical harm if exposed to very high temperatures for too long, though – their exoskeletons might begin to melt, and this will cause them to melt as well. They can also die if burned and not allowed to cool down before too long.
Do Cockroaches Like the Cold?
They can tolerate pretty low temperatures, but they prefer warmer weather. Suppose you’re thinking about keeping them as pets. In that case, it is best to choose one of the species that live in tropical conditions (humidity and high temperature) because keeping them in warm conditions will be much easier than keeping them in cold ones.
Do Cockroaches Have Genders?
Yes, they are either male or female. The male has a “phallus”, which can be compared to the shape of a sabre tooth tiger’s fang. It is an organ that will transfer sperm from the male to the female during mating.