Insects are members of the largest class of the Arthropoda, the largest phylum of the kingdom animalia. They have segmented bodies, jointed legs, and external skeletons (exoskeletons). They are unique among other arthropods by their tri-partite body structure comprising the head, which bears the mouth parts, eyes, and a pair of antennae; the thorax, which usually has three pairs of legs in adults and one or two pairs of wings; and the many-segmented abdomen, which contains the digestive, excretory, and reproductive organs. In terms of habitat, they may either be terrestrial or aquatic. Insects have diversely high reproductive capacity (fecundity). They display varying behavioral and adaptive features that enhance their survival in any environment they live. Certain insects are gregarious– they form gigantic migratory swarms, which travel over hundreds or thousands of miles. On the other hand, there are solitary insects [see] that do not swarm like the gregarious ones.
Often in their bid to survive, insects interfere with human activities. Especially in the area of agriculture, a host of insects interfere with crops and other vegetation available in the environment. While this interference produces positive results, there is a negative side to this interference, which may be serious enough to warrant control measures [see]. The highlights of positive and negative interference of insects with farming are as stated below.
Positive effects of insects:
- Some insects like termites and rhinoceros beetle larvae aid bacteria, fungi, and other organisms in the decomposition of organic matter and in soil formation [see].
- Insects assist in pollination of many flowers.
- Some insects are predators of others, thus assisting in biological control of crop pests.
- Certain insects provide sources of commercially important products such as honey, silk, wax, dyes, or pigments, all of which can be of direct benefit to humans.
- Since the primitive age, insects have been a significant food source, providing a good source of protein for people in some countries.
- The coccids are the source of dye used for dying cloth, in foods, cosmetics, drugs, and textiles [see]
- Waxes produced by insects are of high commercial importance, especially bees wax and lac wax.
- Silks of varying types are produced from the cocoons of large wild silkworm species [see]
- The honeybee produces honey, which is an important sweetener.
Negative effects of insects [see]:
- They destroy crops directly, either in the field or in storage, and convey infection microorganisms to crops, farm animals, and humans.
- They affect humans, causing sicknesses and diseases in farming households.
- They cause indirect damage by acting as vectors and transmitting bacterial, viral, or fungal infection into a crop
- They cause diseases in livestock, leading to low meat and egg production and destruction of hide and skin.
- When crops are harvested, these insects thrive in the stores, reducing their economic value.
- They invariably cause food shortage and hunger in the society.
Although insects are could be destructive in most of their activities through which they interact with man and the environment, they also produce positive influence which promotes sustainable agriculture and food security. Depending on the side of the coin a farmer experiences, he may consider the insect foes or friends. A farmer who has witnessed crop failure due to insect pest invasion considers them as foes. However, when opportunities provided by insects are considered, a farmer may want to regard them as friends.