While we see crickets around us all the time, especially in their natural habitats, like meadows, forests, and grasslands, we rarely think beyond their chirping. Their chirping is fascinating, though. It’s a sound they produce by rubbing their feet together, and it rises in pitch as the weather grows warmer. However, the chirping is not the only amusing thing about these strange-looking, pesky insects. In fact, all insects are pretty enthralling if you’re into observing, discovering, and understanding nature and its creations.
Crickets are a necessary part of the ecosystem and the food chain. They eat anything, from other crickets to fungus, and many other bigger insects eat them. Like every other living being, crickets exist for a purpose; they are a food source for other insects and animals.
Crickets look very much like their cousins, the grasshoppers. With the same antennas, rounded head, and bulging bug eyes, crickets might seem creepy to you, but they’re actually not harmful to humans – mostly. They’re simply a nuisance, with their tell-tale chirping after dark. However, most people see crickets as nothing more than pests that make music that accompanies night time. This is unfortunate because despite being classified as bugs and pests, they are mesmerizing creatures with their own unique set of characteristics.
The resemblance doesn’t end there, though; both the cousins do not have a set of lungs. Something that we deem necessary for survival.
While their respiratory systems and almost every other biological function are very distinct to that of humans, like every other living creature, they need oxygen for survival too. However, since they don’t have lungs, and they don’t circulate oxygen through their bodies like humans and other animals, how do they breathe?
Crickets and other insects have little holes all over their body that lets them absorb oxygen and dispel carbon dioxide. Their respiratory system is basically just a gas diffusion mechanism, where the oxygen diffuses the carbon dioxide from their bodies. They have some control over their respiratory systems and can control these holes to expand or contract to regulate the intake of oxygen, and prevent the loss of moisture.
Insects look like very simple beings, with uncomplicated biological systems, but the truth is that every living thing has a very unique system keeping it alive. Nature is full of strange mysteries like that, and one of them is the mystery of how exactly crickets breathe.
Belonging to the family, Gryllidae, crickets have over 2400 types, including tree crickets, house crickets, and various others. They are omnivores. This means that their diet consists of just about anything from grass, fabric, and fungus, to other crickets if they have no other source of food around. They’re nocturnal insects and feed mostly by night, which is also when they make their characteristic sound. The singing is only characteristic of the male crickets, and the process is called stridulation.
Crickets have a hard exoskeleton to protect themselves from predators. With their strong hind legs for jumping, their defining long antennas, and the ears that are located in their feet, crickets are pretty interesting creatures, even by insect standards. Another weirdly remarkable feature of the humble cricket is its absolute lack of nostrils or lungs, baffling scientists in the past as to how crickets manage to breathe and stay alive.
Understanding External and Internal Respiration in Organisms
To understand how unusual a cricket’s respiratory system is, you have to understand how the normal human and animal respiratory system works.
How do Humans and Animals breathe
Humans, animals, and even birds have a similar process for taking in oxygen and expelling carbon dioxide. They’re all equipped with lungs, which are air-filled sac-like respiratory organs that lie inside our rib cages. When we breathe in air, the diaphragm expands, taking in as much air from the environment as possible. Through a tube called the trachea, the air goes into the lungs. This process is called inspiration.
The internal respiratory system then gets to work by separating the oxygen molecules from the air in our lungs and transporting it throughout the body. The oxygen is broken down, and energy is produced, with carbon dioxide being produced as a by-product of internal respiration.
The carbon dioxide produced cannot stay inside the body, so the lungs expel it by contracting the diaphragm. This pushes the toxic carbon dioxide gas out from the body and back into the environment. This process is called expiration.
While the process for inhaling and exhaling oxygen (breathing) is different and varies with different organisms, the internal respiration process is almost the same for most living beings. No matter how the oxygen got in, once the oxygen is processed and converted into energy, the carbon dioxide is ejected out.
How do Crickets Breathe?
Some people use the reference of a sponge when explaining the cricket’s breathing mechanism. For reference, a sponge absorbs water through the millions of tiny holes on its surface and expels water from the same holes.
Crickets breathe like most insects do, through their tracheal system. They do not have limited orifices that are meant for taking in air, like the mouth or nostrils. Crickets, grasshoppers, locusts, and cockroaches all have a similar mechanism for breathing, as they lack lungs, which all other animals utilize for breathing.
As mentioned above, the trachea is a tube that transports oxygen into the lungs of humans and animals. Insects have a large network of tracheal tubes in their bodies, but unlike in humans, these tubes open on the outside of their bodies. The small resultant holes on the cricket’s exterior are called spiracles, and this is where the oxygen gets in the cricket’s body from.
The spiracles directly take in the oxygen from the air and transport it into the cricket’s body. The cricket doesn’t have lungs that the trachea can lead to, so it transports the oxygen to the cricket’s entire body, bathing all its organs in the oxygen.
Once the cricket’s entire body and organs are bathed in oxygen, the gas diffusion process takes place. This is basically the “breathing” part. The oxygen displaces the carbon dioxide by-product present in the body of the cricket, making space for the oxygen.
The oxygen is then broken down, and it transforms into carbon dioxide. The process continues, with the spiracles taking in oxygen and soaking the cricket’s body and cells with oxygen, and the resultant carbon dioxide being diffused by the intake of more oxygen. The carbon dioxide comes out of the tracheal tubes and through the spiracles, where it is released back into the atmosphere.
The spiracles also assist the insect in regulating the amount of oxygen in the body. In places with limited oxygen available, the cricket can expand the spiracles by contracting its muscles to provide more surface area for the oxygen to get in. In cases of extreme heat, they can shut off some of their spiracles to prevent the loss of moisture.
In 2003, scientists looked at the insect’s breathing more closely and ascertained that crickets and humans don’t really have drastically different mechanisms for breathing. Through advanced X-ray machines that enabled them to observe the breathing system in more detail, the scientists claimed that the trachea in a cricket’s body expands and contracts like an animal lung does. So, while insects don’t have a pair of lungs, their trachea functions like one to keep the cricket alive and breathing perfectly.
Their unique breathing mechanism keeps them alive for about 3 months, which is their average lifespan. Crickets do not live for very long; after they develop into mature adults, they die out naturally or by becoming prey to the hundreds of animals that hunt them for food. These include lizards, rodents, frogs, etc.
You’ve probably heard that crickets drown easily. Knowing what you know now, it is easy to see why. The spiracles on the sides of their bodies absorb water, drowning all their organs and cells. While they can contract their muscles to close the spiracles for a while, they can’t keep it up for long, and eventually give up as water permeates their entire bodies.
Crickets are just one of the insects that breathe through their tracheas. Many other insects do so, and each one of them is as interesting as the last one.
Do crickets have lungs?
Unlike humans and most animals, crickets don’t have traditional lungs. Instead, they have special orifices on their bodies through which they take in oxygen and expel carbon dioxide.
What insects are crickets related to?
Crickets are most closely related to grasshoppers. You can even see the resemblance if you compare the two side-by-side. Both of them share the same antennas, rounded head, and bulging bug eyes.
If crickets don’t have lungs, what do they use to breathe?
Crickets have special orifices on their bodies. These are known as spiracles. Through these spiracles, the crickets take in oxygen and expel carbon dioxide from their bodies.