This newscard is an excerpt from the original article published in the DownToEarth.  It talks about the ecological importance of insects.

Try this PYQ:

Q.Consider the following:

1. Birds
2. Dust blowing
3. Rain
4. Wind blowing

Which of the above spread plant diseases?

(a) 1 and 3 only

(b) 3 and 4 only

(c) 1, 2 and 4 only

(d) 1, 2, 3 and 4

Various threats to insects

• Insects are increasingly susceptible to extinction due to increasing climate crisis.
• They form the basal part of the food pyramid and impact our agriculture ecosystems as well as human health.
• Their extinction can have a cascading effect on the upper levels of the food pyramid.
• Rampant and indiscriminate use of chemicals in commercial agricultural practices, mainly monocropping systems, has been taking a toll on insects in the vicinity of farmlands and plantations.
• While everyone is talking about sustainability in agriculture, the role of insects has largely been ignored.

A few common insects whose existence is taken for granted and their ecological relevance are:

(1) Butterflies

• They are important pollinators like bees.
• Species diversity and density of butterfly indicate a good diversity of plants in an area. Several types of butterflies have specific host plants.
• Climate change, forest degradation, habitat loss, unavailability of hosts and nectar plant species are among major reasons for a decline in butterfly population.
• This leads to loss of plants species that depend on the butterflies for pollination.
• Backyard gardening and growing host plants in public spaces are important strategies to conserve butterfly species.

(2) Dragonflies

• They are one of the most widely recognised insects, need clean aquatic systems and are hence a good indicator of the health of local aquatic systems.
• These, along with damselflies, are well-known biological predators with both larvae and adults acting as natural bio-control agents.
• They are highly sensitive to changes in their habitats and are declining due to increasing habitat loss, anthropogenic activities, pollutants, climate change and rapid urbanisation.
• For their conservation, use of chemical fertilizers and pesticides has to be prohibited or minimized in agriculture systems.

(3) Grasshoppers

• They feed on different plants and can cause serious damage to economic crops.
• However, in a biodiversity-rich region, they are an important component of the food chain, being an important food source for many birds.
• Grasshoppers and insects such as crickets are often consumed by people as they are rich in protein.

(4) Ants

• They are in the most abundance. Ants act as scavengers/decomposers by feeding on organic wastes and other dead animals.
• Ants also aerate the soil.
• Heavy use of chemicals in agriculture causes harm to ants.

(5) Wild honey bees

• They play a major role in the pollination of forest species affecting cross-pollination and maintenance of variability within species.
• Wild honey is also a food source for humans and many wild animals.
• When forest covers are lost, wild bees tend to migrate to newer areas where they may or may not adapt.
• With the possibility of commercial apiaries, wild bees need to be left alone and honey tapping from wild hives discouraged.
• This can help sustain the natural processed of pollination among forest species and maintain diversity in plants conventionally propagated through seeds.

(6) Rainbow leaf beetles

• They are found in forests, woodlands and mountain grasslands.
• They mostly depend on leaves and flowers of some specific plant family like Apocynaceae.
• These are listed as endangered species in International Union for Conservation of Nature from 1994.
• The species is also known to be poisonous to its predators for they feed on dogbane that contains poisonous cardenolides.

(7) Fireflies

• They are a good indicator of a healthy environment, especially a good aquatic system. They avoid regions with chemical toxicity.
• They are good pollinators and natural pest control agents in several ecosystems.

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