Entomology (from Greek= entomon and logos= discourse) is the branch of zoology which deals with insects. It aims at understanding their body organization and functions, their habits, behavior, relation to one another and to the surroundings in which they live, their classification, development, distribution, origin, past history and economic importance. People who study insects are called entomologist. Worldwide there are countless thousands of entomologist observing, collecting and experimenting with insects.
Biologists choose to work with insects for many reasons: the ease of maintaining laboratory cultures, short life cycle and availability of many individuals are important factors. The few ethical problems concerning the responsible experimental use of insects, as compared with vertebrates, is another important consideration. It is a popular perception that entomologists kill or at least control insects but entomology includes many positive aspects of insects since their benefits to us outweigh their harm.
The importance of insects
We should study insects for many reasons. Their ecologies are highly diverse and often they dominate food chains and food webs in biomass and species richness. The feeding specialization of different insect groups range over detritivory, saprophagy, xylophagy, and fungivory, aquatic filter feeding and grazing, phytophagy including sap feeding and carnivory (predation and parasitism). Other insect group shows various combinations of these major feeding types. Insects may be aquatic or terrestrial throughout, or during part of their lives. Their lifestyles encompass solitary, gregarious. Subsocial and highly social modes. They may be conspicuous or concealed and active by day or night. Insect life cycles are adapted to a variety of abiotic conditions, including seasonal extremes of heat and cold, wet and dry, and notably to unpredictable climate.
Insects are essential in the following roles within ecosystems:
� Nutrient recycling via leaf-litter and wood degradation, carrion and dung disposal, and soil turnover.
� Plant pollination and sometimes seed dispersal.
� Maintenance of plant community composition and structure via phytophagy, including seed feeding.
� Supporting insectivorous animals, such as many birds, mammals, reptiles and fish.
Each insect species is part of a wider community and if lost, the complexities and abundance of other life will be affected.
Insects also contain a vast array of chemical compounds, some of which can be collected, extracted or synthesized and used by ourselves. Silk from the coccons of silk worm moths, Bombyx mori, has been used for fabric for centuries. The red dye, cochineal, is obtained commercially from scale insects of Dactylopius coccus cultured on Opuntia cacti. Another scale insect, the lac insect Kerria lacca, is a source of a commercial varnish called shellac. Chitin, a component of insect cuticle or derivative of chitin, can act as an anticoagulant or haemostatic agent for tissue repair in humans, enhancing the healing of wounds and burns, reducing serum cholesterol, serving as a non allergenic drug carrier, providing a biodegradable plastic of high tensile strength, and enhancing the removal of pollutants from waste water etc.
Charactristics of certain insects make them useful models for understanding biological processes in general. For instance, the now widespread vinegar fly, Drosophila melanogaster has a short generation time, high fecundity and ease of laboratory rearing, and manipulation making it ideal for generic and cytological research.
The study of insecta as human food is an increasingly popular field of entomology. About 500 species of insects in more than 260 genera and 70 families are used for food somewhere in the world, especially in central and southern Africa, Asia, Australia and Latin America.
Lastly and perhaps the most importantly, the sheer number of insects means that their impact upon the environment, and hence our lives, is highly significant. Insects are the major component of biodiversity and if only for this reason, we should try to understand them better.
