What is an insect?
Insects are a group within the phylum Arthropoda. It is the most diverse group of animals on land! There are almost a million different species of insects on the planet, and in Sweden there are around 33,000 species. Insects are found all over the world. They are highly adaptable and range in size from less than a millimetre, to almost half a metre long! There are many species of insects that migrate over large areas, just like migratory birds. The science of insects is called entomology.
Insects have been around for millions of years, and some have changed and adapted a lot during evolution. The oldest fossils found of insects are 400 million years old! Fossils have been found of dragonfly-like insects that were 70 cm between the tips of their wings.
Did you know there are migratory butterflies? The red admiral flies thousands of kilometers from north to south and back again, every year. It is one of the longest animal migrations in the world! Red admirals navigate by using the Sun, and the Earth's magnetic field.
Photo: NTNU-Vitenskapsmuseet-CC-BY
Insects, like this southern hawker, have an exoskeleton. It is a hard exterior, which protects their soft bodies. In order to grow, insects shed their exoskeleton and replace the old shell that no longer fits.
Photo: WWalas-CC-BY-SA
Most insects have two pairs of wings, and in beetles, one pair is called elytra (or hardened forewings) and the other is called hindwings. The elytra can be lifted up to expose the thin hindwings. When the beetle is not using its hindwings, they are folded and hidden under the protective elytra.
Photo: Hedwig-Storch-CC-BY-SA
Flies, mosquitoes, and crane flies may appear to have only one pair of wings, but they actually have two pairs! The second pair looks like small knobs and is called halteres. They are modified wings that, through evolution, have acquired the function of helping the insect maintain balance while flying. The halteres oscillate back and forth at a high frequency to assist insects in navigating through the air more efficiently.
Photo: Géry-PARENT-CC-BY-SA
Did you know that there are almost a million species of insects on our planet? Scientists also believe that there may be up to 4 million more that we have not yet discovered. Insects come in many shapes and forms, from shiny beetles and colorful butterflies to a tiny fly. But all have an important role to play in the ecosystem!
About 200 million years ago, during the Jurassic period, this dragonfly lived along with the dinosaurs. Fossils like this give us a glimpse of what life was like on Earth long before humans existed. Although dragonflies have existed on Earth for millions of years, their basic appearance and lifestyle have remained unchanged.
Compare the image of this southern hawker with the fossil dragonfly image, and you will see that the dragonflies of today are very similar to the dragonflies of the time of the dinosaurs.
Photo: Bohringer-CC-BY-SA
Insects come in many shapes and sizes. Each insect's head is adapted to its lifestyle and needs. Some have large eyes to see in the dark or search for food, while others have powerful jaws to defend themselves or chew through prey. Regardless of appearance, these different faces help the insects survive and thrive in their specific environment.
Photo: Andrei-Savitsky-CC-BY
Did you know there are migratory butterflies? The red admiral flies thousands of kilometers from north to south and back again, every year. It is one of the longest animal migrations in the world! Red admirals navigate by using the Sun, and the Earth's magnetic field.
Photo: NTNU-Vitenskapsmuseet-CC-BY
Insects, like this southern hawker, have an exoskeleton. It is a hard exterior, which protects their soft bodies. In order to grow, insects shed their exoskeleton and replace the old shell that no longer fits.
Photo: WWalas-CC-BY-SA
Most insects have two pairs of wings, and in beetles, one pair is called elytra (or hardened forewings) and the other is called hindwings. The elytra can be lifted up to expose the thin hindwings. When the beetle is not using its hindwings, they are folded and hidden under the protective elytra.
Photo: Hedwig-Storch-CC-BY-SA
Flies, mosquitoes, and crane flies may appear to have only one pair of wings, but they actually have two pairs! The second pair looks like small knobs and is called halteres. They are modified wings that, through evolution, have acquired the function of helping the insect maintain balance while flying. The halteres oscillate back and forth at a high frequency to assist insects in navigating through the air more efficiently.
Photo: Géry-PARENT-CC-BY-SA
Did you know that there are almost a million species of insects on our planet? Scientists also believe that there may be up to 4 million more that we have not yet discovered. Insects come in many shapes and forms, from shiny beetles and colorful butterflies to a tiny fly. But all have an important role to play in the ecosystem!
About 200 million years ago, during the Jurassic period, this dragonfly lived along with the dinosaurs. Fossils like this give us a glimpse of what life was like on Earth long before humans existed. Although dragonflies have existed on Earth for millions of years, their basic appearance and lifestyle have remained unchanged.
Compare the image of this southern hawker with the fossil dragonfly image, and you will see that the dragonflies of today are very similar to the dragonflies of the time of the dinosaurs.
Photo: Bohringer-CC-BY-SA
Insects come in many shapes and sizes. Each insect's head is adapted to its lifestyle and needs. Some have large eyes to see in the dark or search for food, while others have powerful jaws to defend themselves or chew through prey. Regardless of appearance, these different faces help the insects survive and thrive in their specific environment.
Photo: Andrei-Savitsky-CC-BY
The exoskeleton of the body
Insects have their skeleton on the outside. This is called an exoskeleton, and it is hardened skin that acts like a shell. Usually insects have 6 legs, but in some species one of the pairs of legs may be transformed, making them useless for walking. Instead of lungs or gills, insects breathe through so-called tracheae, which are tubular passages through the body. Some species instead have buccal lungs, a kind of blood-filled disc that absorbs oxygen from the air.
Almost all insects have wings, either one or two pairs. All insects have a body that is divided into three parts: head, thorax and abdomen. The head has antennae and mouthparts with specially adapted jaws and eyes.
Insects have three distinct body parts - the head, thorax, and abdomen. The head contains the eyes, antennae, and mouthparts. The thorax has three pairs of legs and usually one or two pairs of wings for flying. In the abdomen, the insect has its stomach, intestines, and reproductive organs.
Photo: Richard-Bartz-CC-BY-SA
Flies have compound eyes, which are divided into many small parts called facets. Each facet functions as a tiny lens that captures light from different directions. Because each facet gives a small piece of the image that the fly sees, compound eyes also help flies detect movement from multiple directions at the same time. Insects can also have simple eyes, small spots which are very light-sensitive but do not create any images.
Photo: stephane400-CC-BY-NC
Most insects breathe through a network of small tubes called tracheae that extend throughout their bodies. Air enters through tiny pores called spiracles, located on the sides of the body, and is then distributed through the tracheae to all parts of the insect. In this way, insects obtain oxygen directly to their cells without lungs.
Photo: Geoff-Gallice-CC-BY
Insects that live in water breathe through a combination of tracheae and gills, like this diving beetle.
Insects have three distinct body parts - the head, thorax, and abdomen. The head contains the eyes, antennae, and mouthparts. The thorax has three pairs of legs and usually one or two pairs of wings for flying. In the abdomen, the insect has its stomach, intestines, and reproductive organs.
Photo: Richard-Bartz-CC-BY-SA
Flies have compound eyes, which are divided into many small parts called facets. Each facet functions as a tiny lens that captures light from different directions. Because each facet gives a small piece of the image that the fly sees, compound eyes also help flies detect movement from multiple directions at the same time. Insects can also have simple eyes, small spots which are very light-sensitive but do not create any images.
Photo: stephane400-CC-BY-NC
Most insects breathe through a network of small tubes called tracheae that extend throughout their bodies. Air enters through tiny pores called spiracles, located on the sides of the body, and is then distributed through the tracheae to all parts of the insect. In this way, insects obtain oxygen directly to their cells without lungs.
Photo: Geoff-Gallice-CC-BY
Insects that live in water breathe through a combination of tracheae and gills, like this diving beetle.
Beneficial insects and insects that bite
All insects have a function in the ecosystem, and many are vital for human survival. Perhaps most important are the insects that pollinate plants. Without pollination, many plants would not be able to multiply, and no fruits, berries or nuts would be able to form. In Sweden, it is mainly bees and bumblebees, but also certain groups of butterflies, hoverflies and beetles that pollinate.
Different insect species are adapted to eat many different things. They help break down plant material, fungi and dead animals in nature. They are also food for many other animals such as birds, frogs and some mammals.
However, humans view many insects as pests. A lot of people find flies and cockroaches disgusting, and they can also spread disease and dirt. Locusts are capable of swarming in huge numbers, and can devour agricultural crops. Biting flies can gather in huge numbers and bite grazing animals like horses and cows so badly that they become acutely ill. Some mosquitoes, like the malaria mosquito, can spread serious diseases. But usually, pests become so numerous because humans have changed the environment in various ways.
Temporary swarms of insects can cause significant damage to crops. Here, locusts are moving in huge groups in Madagascar.
Photo: Iwoelbern-CC-BY-SA
Many people find cockroaches disgusting because they have adapted well to human environments and can come very close to us. However, as a group, they are very impressive insects that have existed on Earth for hundreds of millions of years.
Photo: Peterwchen-CC-BY-SA
The malaria mosquito lives in warm and humid areas around the world and seeks blood from humans and animals to survive. When a malaria mosquito feeds on a person who carries malaria parasites, the mosquito can become infected and then transfer the parasites to other people through its next blood meal. Malaria is a serious illness that can lead to fever, headache, fatigue, and sometimes even death. Malaria existed in Sweden until the 1930s.
Even though it may sound unusual to many people, there are many benefits to eating insects. Insects are a nutritious source of protein, vitamins, and minerals. By eating insects, we can reduce our carbon footprint as insects produce fewer greenhouse gases than other types of food production.
Photo: shankar-s.-CC-BY
Bumblebees, like many other insects, help to pollinate flowers by transferring pollen from one flower to another. This allows the flowers to create new seeds. The furry bodies of bumblebees make them excellent pollinators, as pollen sticks to their hair while they search for nectar.
Photo: Ivar-Leidus-CC-BY-SA
Many insect larvae, such as flies and beetles, feed on decaying plants or animal carcasses, breaking them down into smaller pieces. This helps to spread nutrients from organic material to the soil, building up a fertile soil for plants to grow in. It is an important part of the ecosystem, as the larvae help to return nutrients to the soil and enable new organisms to grow.
Photo: Magne-Flaten-CC-BY-SA
Insects are an important part of many animals' diets, and they can provide protein and other important nutrients needed to survive. Insects are particularly important food for bird chicks when they need a lot of energy to grow.
Photo: Kathy-Büscher-CC-BY
Temporary swarms of insects can cause significant damage to crops. Here, locusts are moving in huge groups in Madagascar.
Photo: Iwoelbern-CC-BY-SA
Many people find cockroaches disgusting because they have adapted well to human environments and can come very close to us. However, as a group, they are very impressive insects that have existed on Earth for hundreds of millions of years.
Photo: Peterwchen-CC-BY-SA
The malaria mosquito lives in warm and humid areas around the world and seeks blood from humans and animals to survive. When a malaria mosquito feeds on a person who carries malaria parasites, the mosquito can become infected and then transfer the parasites to other people through its next blood meal. Malaria is a serious illness that can lead to fever, headache, fatigue, and sometimes even death. Malaria existed in Sweden until the 1930s.
Even though it may sound unusual to many people, there are many benefits to eating insects. Insects are a nutritious source of protein, vitamins, and minerals. By eating insects, we can reduce our carbon footprint as insects produce fewer greenhouse gases than other types of food production.
Photo: shankar-s.-CC-BY
Bumblebees, like many other insects, help to pollinate flowers by transferring pollen from one flower to another. This allows the flowers to create new seeds. The furry bodies of bumblebees make them excellent pollinators, as pollen sticks to their hair while they search for nectar.
Photo: Ivar-Leidus-CC-BY-SA
Many insect larvae, such as flies and beetles, feed on decaying plants or animal carcasses, breaking them down into smaller pieces. This helps to spread nutrients from organic material to the soil, building up a fertile soil for plants to grow in. It is an important part of the ecosystem, as the larvae help to return nutrients to the soil and enable new organisms to grow.
Photo: Magne-Flaten-CC-BY-SA
Insects are an important part of many animals' diets, and they can provide protein and other important nutrients needed to survive. Insects are particularly important food for bird chicks when they need a lot of energy to grow.
Photo: Kathy-Büscher-CC-BY
Temporary swarms of insects can cause significant damage to crops. Here, locusts are moving in huge groups in Madagascar.
Photo: Iwoelbern-CC-BY-SA
Insects as food for humans?
There are a large number of insects such as beetles, larvae, grasshoppers, crickets and ants that are eaten by humans today. In the future, humans are likely to farm and eat larger quantities of insects. This will have a much smaller impact on the climate than some of today’s food production, and will significantly improve animal welfare. Today, many mammals and poultry are raised for meat, which deprives them of their basic, natural needs and behaviours.