Insects, which are classified in the Class Insecta, are found in almost every kind of habitat on Earth, in a spectacular array of forems. They are the most numerous and diverse group of all animals, and the vast majority have never been formally identified. There are currently over a million described species, yet some experts think that there may be as many as ten million in total. So far, science has recorded around 360,000 species of beetle, 180,000 species of butterfly and moth, 120,000 fly species, 110,000 species of bee, wasps and ants, 82,000 true bug species, 20,000 species of grasshoppers, 5,000 dragonfly species, 2,000 praying mantids, and many, many other. Tragically, large number of insect across the world are being made extinct as the result of human activities such as rampant deforestation and widespread pollution.
Unlike many other animals, insects have to go through a complicated series of stages to reach adulthood. This process known as metamorphosis characteristically begins with an egg that hatches into a larva. It then undergoes several stages called “instars”, each of which is separated by a skin moult. At the final moult, the larva changes into a pupa, and then emerges from this some time later as an adult. However, this is an oversimplication of the process, as there are three entirely different types of metamorphic cycle. These are known as ametabolous, hemimetabolous andholometabolous processes.
Ametabolous insects, such as bristletails, emerge from the egg as small versions of the adult and simply grow bigger until they themselves are adult-sized and sexually mature. Hemimetabolous insects emerge from the egg as nymph (terrestrial species) or naiads (aquatic species), and change into adults via a series of small changes at each moult. Holometabolous insects undergo the full process outlined above-namely an egg, followed by the larva, then a pupa and finally the adult. The timing of the change in all three metamorphic regimes may be linked to a number of environmental conditions, but are ultimately controlled by the release of special hormones by the brain.
By far the most efficient insect predators are other insects. These include the praying mantids, parasitic wasps and flies, carnivorous hornets and beetles, aerial dragonflies, and many kinds of water bugs. Outside the insect kingdom, many animals are extremely well adapted to hunt and eat them too. Among the vertebrates, this includes everything from mice to hedgehogs, anteaters, monkeys, reptiles, amphibians, and of course birds. Invertebrate predators include spiders, scorpions, centipedes, millipedes and others. One of the most insidious of all natural control systems, however are various kinds of fungus these find their way into the breathing tubes of many kinds of insects and kill them from within.
In spite of all the media attention directed at reducing the amount of deforestation and other environmental damage, large numbers of animals and plants are still being made extinct. No one knows how many insects are included in this toll, and so it is vital that conservation efforts are maintained. Habitat loss is by far the biggest problem, and although many governments pass new laws to protect their natural environments, few actually enforce the regulations adequately. As individuals, the best thing we can do is to ensure that whatever land we have access to is managed in an insect-friendly manner. If everyone with a garden made the effort to provide food and shelter for wild creatures, the whole ecosystem would benefit. To this extent, it is important to gain a thorough understanding of what will and will not help. For example, hiding a patch of nettles ‘ for the butterflies ‘ behind a shed or in a shady corner may appear to be a significant gesture, but in fact most of the species that feed on them are very particular about where the plants are situated. If they are not in a sufficiently well-lit and ventilated location, any larvae would quickly succumb to fungal infections. Consequently, Small Tortoiseshells, Peacocks and other nettle-feeding species will not lay their eggs on them. It would be far better to use an area as a safe insects over-wintering zone by stacking some old logs in a position where they will not get disturbed. Establishing a pond is an even better idea, although stocking it with fish will result in any insects being eaten before they can make it to adulthood. There is a lot of information about specific conservation measures to be found in books, magazines, and on the internet, as well as with local natural history and gardening societies. At the end of the day, our planet’s environment is under extreme pressure, and its wild spaces need all the help they can get !!!!!!!