Arthropods: Insects

Maria and Sofia are out exploring. Sofia notices something interesting moving on the ground. It’s a long line of ants! Take a closer look at them with your magnifying glass, Sofia. Look!

The body of an ant is divided into three segments - the head, the thorax, and the abdomen. It has 6 legs, all attached to the thorax. There is a pair of antennae on its head, that the ant uses to sense its environment. There are also three simple, single-lens eyes, and a pair of eyes with several lenses, also called compound eyes. And these bits here, at the front of its head, are the three mouthparts that the ant uses to feed.

It’s not only all species of ants that have these body characteristics. Silverfish, beetles, praying mantises, even bees, moths, and butterflies also have all these features. All these types of animals, and many more, belong to the same group or CLASS of animals - they are all INSECTS. But if we take, for example, an ant and a butterfly, there is one obvious difference between these. The butterfly has wings!

Normally, butterflies and other insects that have wings, have two pairs of them, attached to the thorax. How the wings look varies a lot though. Butterflies have two pairs of very thin wings, but beetles, for example, have one pair of very thick, armour-like wings, and one pair of thin wings underneath. And insects don’t use wings just for flying! Hard wings can be used for protection, while colourful wings can warn off predators, or attract mates.

There is another feature that all insects have in common - they all go through a transformation phase, also called metamorphosis, before reaching the mature adult stage. When young, some insects, like praying mantises, look like adults apart from not having wings. They change gradually by shedding, or moulting - a process called incomplete metamorphosis. Whereas other kinds of insects, like moths, go through four very distinct phases. When they hatch from the egg, they have a worm-like shape we call larva, that then grows and becomes a pupa.

As pupae, insects go through a complete transformation and emerge as adults. This process is called complete metamorphosis. Insects are an incredibly diverse and adaptable group of animals. More than half of all known living organisms are insects. They function as pollinators, and as food for other animals, which makes them extremely important for the proper functioning of all ecosystems.

Humans rely on insects much more than we realise - most of the food on our plates would not be there if not for the insects pollinating the plants that we farm! But a lot of species are now threatened by the loss of their habitat, use of chemicals in farming, pollution, and climate change. We must not let insects become extinct, but what can we do to protect them? For example, Maria and Sofia could plant some good insect “food” in the garden, like a variety of flowering plants. Or, they could make a “bug hotel” using wood scraps, leaves and sticks, to provide a safe place for insects to rest and hide from predators and bad weather.