🩰 Beneficial Insects

Helpful Insects Parasites

• These are small insects which feed and live on harmful insects by completing their life cycle in a host and kill the host insect.
• These can be
  • Egg Parasitoids (A parasite feed on another Parasite’s Eggs)
  • Larval Parasitoids (A parasite feed on another Parasite’s Larva)
  • Pupal Parasitoids (A parasite feed on another Parasite’s Pupa)
• These are used for biological control of pests and are integral part of any Integrated Pest Management Programs.

Predators

• These are large insects which capture and devour harmful insects.
• E.g., Coccinellids, Preying mantis etc.

  

Pollinators

• Many cross-pollinated plants depend on insects for pollination and fruit set.
• E.g., Honeybees, aid in pollination of sunflower crop.

Weed Killers

• Insects which feed on weeds, kill them thereby killers.
• Many insects feed upon unwanted weeds, just the same manner they do with cultivated plants.
• E.g.
  • The classical example being Prickly Pear control with cochineal insect, Dactylopius tomentosus.
  • Water-hyacinth is a free-floating freshwater plant. It impedes flow of irrigation water, interferes with pisciculture etc. and can be effectively controlled by two weevils namely Neochetina eichhorniae and Neochetina bruchi and mite Orthogalumna terebrantis.
  • Control of Parthenium hysterophorus by beetle Zygogramma bicolorata.
• We have already covered the examples of weed killers in Agronomy Course

Soil Builders

• Soil insects such as ants, beetles, larval of cutworms, crickets, collembola, make tunnels in soil and facilitate aeration in soil.
• They become good manure after death and enrich soil.

Scavengers

• Insects which feed on dead and decaying matter are called scavengers.
• They are important for maintaining hygiene in the surroundings.
• Since insects help to remove from the earth surface the dead and decomposing bodies, which would otherwise be a health hazard, they are referred to as scavengers.
• The following are the important groups of insects that serve as scavengers in nature:
• Coleoptera: Rove beetles, Chafer beetles, Ptilinid beetles, Darkling beetles, Skin beetles, Nitidulids, Carrion beetles, Jewel beetles, Water scavenger beetles, Powder post beetles and bostrychids.

  

• Diptera
  • Sand flies or moth flies
  • Hover flies
  • Root maggot flies
  • Termites (Isoptera: White Ants)
  • Ants (Hymenoptera: Ants)

    

• These also live and feed upon dead wood, dead animal, or decaying vegetable matter.

Useful as Drugs, Food, and Ornaments

• As medicine e.g. Sting of honey bees - remedy for rheumatism and arthritis.
• Eanthoridin - extracted from blister beetle – useful as hair tonic.
• They have been used as food by human beings in different parts of the world.
• For animals - aquatic insects used as fish food.
• Eg. Grasshoppers, termites, pupa of moths.

Cochineal

• A crimson colour dye (carminic acid) is obtained from Dactylopius ceylonicus.

Cantharidin

• Cantharidin is a substance derived from the blister beetle and has medicinal properties.

  

• Is obtained from haemocoel and accessory glands of male genetalia of meloid (blister) beetles.
• Anthroquinone is present in cochineal red and lac.

  

• Insect galls contain 30-70% Tannic acid.
• Insect galls contain Indole Acetic Acid (IAA).

  

Ornaments, entertainers

• Artists and designers, copy colours of butterflies.
• Beetles & worm as necklace
• Insect collection is also an hobby.

Scientific research

• Drosophila and mosquitoes are useful in genetic and toxicological studies respectively.
• Blow flies are used in forensic investigation.

  

- https://nisa.icar.gov.in/
- http://npic.orst.edu/envir/beneficial/index.html
- https://agritech.tnau.ac.in/
- Wikipedia