Entomologists claim that insects are the most successful creatures on earth. They are the most numerous in terms of species and numbers and they are found in most, if not all, habitats on every continent.
More than a million insect species are known to science. These make up more than half the living things known up to now and it is estimated that there could be anything between 25 and 30 million insect species still to be discovered which would make up 90 per cent of all living organisms.
Even Malta has its fair share of undiscovered species and every year entomologists discover species that are new to science.
Part of the success of insects is due to their size and structure. Insects can be so small that they can hardly be seen with the naked eye and can occupy the smallest of habitats. Their body is encased in an exoskeleton which protects the internal soft tissues, including the muscles which are anchored to the skeleton.
Most insects start life as an egg. The female insect lays her eggs on or close to the larvae’s food to ensure that as soon as the eggs hatch the larvae can immediately start to feed, which is what they will do throughout their life as a larva. Most larvae are nothing more than a mouth and a rectum connected together by an efficient alimentary canal wrapped in an exoskeleton.
Even Malta has its fair share of undiscovered species
Once hardened, an exoskeleton cannot grow further. An immature insect grows out of its skeleton as soon as it has formed a new soft one underneath. During this stage an insect goes through several skeletons each one larger than the previous one. The change from one skeleton to another can take place in rapid succession or over a long period of time, depending on how long it takes for a larva to develop.
The process that insects go through when developing is known as metamorphosis. There are two types of metamorphosis: incomplete and complete. In insects with an incomplete metamorphosis, such as dragonflies, the immature stage is known as a nymph. Nymphs look like adults except that they do not have wings. The wings appear only after the final molt.
Insects with a complete metamorphosis go through an extra stage. The larva looks like a worm. When fully grown it changes into a pupa inside which the body is broken down and changes into an adult. Butterflies are the best known example of insects with a complete metamorphosis.
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