The decline in Insect Population

What is the issue?

A study titled 'Worldwide decline of the entomofauna: A review of its drivers' was published recently.
Insect populations are declining sharply worldwide, which could potentially cause the collapse of the planet's ecosystems.

What are the key findings?

More than 40% of insect species could become extinct in the next few decades.
The extinction rate is eight times faster than that of mammals, birds and reptiles.
In addition to this, one third of insect species are endangered.
Insect biomass is declining by 2.5% a year; there is a threat that all of the planet’s insects could go extinct within a century.
Large numbers of specialist insects, which fill a specific ecological niche, and general insects are declining.
On the other hand, a small group of adaptable insects are rising in numbers, but nowhere near enough to arrest the decline.
An earlier study found that flying insect populations in German nature reserves declined by more than 75% over the duration of a 27-year study.
This indicates that die-off is happening even beyond areas affected by human activity, in locations meant to preserve biodiversity.

Why are insects important?

Bugs make up around 70% of all animal species.
The study stresses on the importance of insect life on interconnected ecosystems and the food chain.
The ecosystem at the bottom level which includes insects has to be in balance.
Insects have been at the structural and functional base of many of the world's ecosystems, since their rise almost 400 million years ago.
In a way, insects are the small creatures that run the world.
In the event of any imbalance, the "bottom-up" effects of insect loss would be serious.

What is the likely impact?

The decline in insect population and extinct could potentially cause the collapse of the ecosystems with a catastrophic effect on life on Earth.
If there are no insects as moderators of other pest populations, insect populations would increase and ruin crops and make them difficult to grow.
Species that rely on insects as their food source and the predators higher up the food chain which eat those species are likely to suffer more.
An immediate danger is the loss of insectivorous birds, and the risk of larger birds turning from eating insects to eating each other (birds).
The pollination of both crops and wild plants would also be affected, along with nutrient cycling in the soil.
[Some 80% of wild plants use insects for pollination while 60% of birds rely on insects as a food source.]
Lepidoptera, the order of insects that includes butterflies and moths, seems to have suffered the most.
Bees (belonging to the Hymenoptera order) have been equally hard hit by the current decline in insect numbers.
Most insects are particular about the kind of soil they inhabit; their absence can be a serious indicator of soil health too.

What are the causes for the decline?

What is to be done?

The findings call for an immediate and decisive action to avert a catastrophic collapse of nature's ecosystems.
Overhauling existing agricultural methods is essential at this stage.
Particularly, a serious reduction in pesticide usage and its substitution with more sustainable, ecologically-based practices is needed.

Source: Indian Express, CNN