INSECTS - A GENERAL INTRODUCTION
| Insects are literally 'everywhere'.
Their remarkable adaptability, strength in numbers and high reproductive
rates have helped them to become without doubt the most dominant form of
life on earth. To back up thus statement the question must be asked
that 'If all insects were non-existent tomorrow then what sort of world
would we have within twelve months of their demise?'. A key factor
in the food chain and the whole ecological balance, insects are precious
in the extreme and yet are often overlooked and treated with
disdain. But just what are insects?
Insects are characterised by several distinguishing features which sets them apart from any other group of organisms. 1. The first and most obvious feature is that all insects have 6 legs. These appendages are all attached to the thorax as well as the wings. If it doesn't have 6 legs then it's not an insect. 2. An insects body is composed of 3 parts - head, thorax and abdomen. Remember INSECT = IN SECTIONS. 3. An insect has an external skeleton (exoskeleton) rather than an internal one. This is mainly composed of chitin. 4. Most insects possess 2 pairs of wings. It is important to remember that there are many small creatures that many of us consider as insects but upon examination are in fact members of other groups, for example:- Woodlice (crustaceans), Centipedes and Millipedes (myriapods) and most famously Spiders (Arachnids). |