Some insects are helpful for agriculture and human welfare but some insects are pests of our crop and some insects have poisonous nature. Here we study some beneficial and harmful importance of insects.
A- Beneficial Insects
1- Insects and insects product in the food
Insects are an abundant food supply for several animals like frogs, snakes and small fishes, etc depend on insects for food. In several countries, the human population also uses insects as a portion of food it depends on the choice of the native population of the particular country. Some insect products such as honey are used as food in human beings.
2- Insects as a scavenger
Some insects such as houseflies, silverfish, termites, maggots, dung-beetles, etc. feed upon waste material like a dead and decaying matter of insects and plants, thus act as scavengers and remove dead and decaying materials from the environment.
3- Insects as pollinators for flowers
Some beneficial insects act as the pollinator for several flowers, it means transfer pollen grain from the anther of one flower to the stigma of the same or another flower of the same species. Flowers of some plants are adapted for pollination only by insects such as Ficus racemosa. Some plants secrete nectar to attract insects for pollination. Insects come to flower for nectar and pollinate the flower.
4- Insects in medicine
Some insects used as medicine, such as Cochineal insects contain carminic acid, used for the treatment of whooping cough. Cantharidine oil obtained from bristle beetles serves as a hair restorer. Bombax mori is used for treating leucorrhoea and chronic diarrhea.
5- Insects in biological Paste control
Some beneficial insects feed on another insect which damage crops, these beneficial insects feeding on harmful insects are used as biological paste controller.
6- Insects in fine arts
We all know insects produce noises in various ways, in some countries insects sound used as music. Japan celebrates an annual function, as “festival of the singing insects”.
7- Productive insects
a- Honey producing insect
Honey is produced by the honey bee “Apis”. Honey is good food for human beings.
b- Bee-wax producing insect
Bee-wax is also a product of the honey bee “Apis”. It is used in polish, wax production, and to wax the thread. A few scale insects also wax producing.
c- Silk producing insects
Silk is produced by Bombyx mori and other silkworms. Cocoons of the insects are unwound to spin silk thread.
d- Lac producing insects
Lac or shellac for commerce is obtained from female lac insects (Tachardia lacca). Female secrete lac use for shellac formation.
Dyes such as tannin, cochineal, and crimson lake are obtained from dried bodies of certain scale insects living on cacti.
B- Harmful insects
1- Paste of plants, fruits, and stores grains
Insects feed on several parts of green plants and crops, such as leaves, stems, buds, flowers, fruits, and seeds. Several stored products such as wool, feather, cigars, tools are also damaged by insects. Locusts move in swarms of several Kilometer long, when these swarms attack the crop damage the whole crop of fields of an area.
2- Household pests
Several insects are living in our house, and annoy ourselves, such as mosquitoes, bedbug, may suck our blood and disturb us. They live in our house as unwanted guests and destruct our household products, such as ants, cockroaches, termites, silverfish, spoil our food, damage our cloth and book, and wood of window and door. Cloth moth carpet beetle may destroy the carpets, furs, and feathers.
3- Injurious to domestic animals
Many insects affect domestic animals as parasites, some are ectoparasites such as fleas, lice, bugs, mosquitoes, and a few can live as endoparasites such as bolt-fly larvae in sheep. They irritate our domestic animals, such as bird lice feed upon feathers of chicken, causing irritation and loss of flesh.
4- Disease carriers or an intermediate host of several pathogens
Several insects act as disease or n intermediate host of several pathogens and transfer disease from one pathogen to human to another, hence spread disease in population called as the vector of this particular disease. Some insects which act as vector and secondary host of the pathogen are described here.
a- Anopheles mosquitoes
Anopheles mosquitoes transfer malarian parasites “Plasmodium” from one human to another, if we can control the anopheles population we can control malaria.
b- Aedes mosquitoes
Spread yellow fever and dengue in the human population, means spread the viral fever. Dengue and yellow fever occur in high frequency where Aedes mosquitoes occur in large numbers.
c- Culex mosquitoes
Filariasis is spread by Culex mosquitoes. Culex acts as the intermediate host of filarian worms and transfers filarian worms from the infected human to healthy persons.
d- Tsetse fly (Glossina palpalis)
Tsetse fly spreads African sleeping sickness, acts as the intermediate host of Trypanosoma gambiense. Hence, spread sleeping sickness in the human population.
e- Sand fly (Phlebotomus)
Act as intermediate host of Leishmania donovani and spread kala-azar in human populations.
f- Housefly (Musca)
Spread food and water-borne disease in human populations, housefly cause contamination in food and water. By eating and drinking this food and water we can affect by diseases such as diarrhea, Cholera, etc.
References and Sources
- A Text-Book of Zoology Invertebrates by R.L. Kotpal, Tenth edition.
- https://pets-animals.blurtit.com/3751878/how-insects-are-used-to-produce-biological-products – 2%
- https://en.wikipedia.org/wiki/Insect – 2%
- https://en.m.wikipedia.org/wiki/Insects_in_medicine – 2%
- https://www.studyread.com/importance-of-insects/ – 1%
- https://www.researchgate.net/publication/315683761_INSECTS_FRIENDS_OR_ENEMIES – 1%
- https://www.pollinator.org/pollinator.org/assets/generalFiles/Gardens-Curriculum-2010-one-doc.pdf – 1%
- https://en.wikipedia.org/wiki/Tsetse_fly – 1%