Insects may be tiny, but there are more of them than all the other animals put together – over 1 million known species.
They range from tiny flies to huge beetles, and they are found everywhere there is land.
Insects have six legs and a body that is divided into three sections – which is why they are called insects sections’). The sections are the head, thorax (middle) and abdomen.
An insect’s body is encased in such a tough shell (its exoskeleton) that there is no need for bones.
Insects grow by getting rid of their old exoskeleton and replacing it with a bigger one. This is called molting.
Insects change dramatically as they grow. Butterflies, moths, and beetles undergo metamorphosis (see butterflies). Grasshoppers and mayflies begin as wingless nymphs, and then gradually grow wings with each molt. Silverfish and springtails simply get bigger with each molt.
Insects’ eyes are called compound because they are made up of many lenses – from six (worker ants) to more than 30,000 (dragonflies).
Insects have two antennae (feelers) on their heads.
Insects do not have lungs. Instead, they breathe through holes in their sides called spiracles, linked to their body through tubes called tracheae.
The world’s longest insect is the giant stick insect of Indonesia, which can grow to 33 cm long.
The bold coloring of the ladybird warns birds that it is not for eating. It has a healthy appetite for aphids making it every gardener’s friend.
Insects are small, but many have nasty poisons to protect themselves.
Most poisonous insects are brightly colored including many caterpillars, wasps and cardinal beetles – to warn off potential enemies.
Ants, bees and wasps have stings in their tails which they use to inject poison to defend themselves or paralyze prey.
Bee and wasp stings have barbed ends to keep the sting in long enough to inject the poison. Honey bees cannot pull the barb out from human skins, and so tear themselves away and die.
The hornet is really a large wasp. Its brightly striped body is a warning to others animals that it stings. When the hornet does sting, it injects venom that causes a painful swelling.
Velvet ants are not really ants at all, but wingless wasps with such a nasty sting that they are called cow killers.
Ladybirds make nasty chemicals in their knees.
When they are attacked, swallowtail caterpillars whip out a smelly forked gland from a pocket behind their head and hit their attacker with it.
The lubber grasshopper is slow moving, but when attacked it oozes a foul smelling froth from its mouth and thorax.
The bombardier beetle squirts out a spray of liquid from its rear end, almost like a small spray-gun! This startles and stings the attacker and gives the small beetle time to escape.