Insects

According to the Smithsonian Museum, there are 900,000 identified insects and many more that have not been identified.  It is estimated that insects also probably have the largest biomass of the terrestrial animals.  Small they may be (usually less than 5mm long) but they cannot be ignored.  Indeed, it would be surprising if such a common organism were not to be significant for our planet.

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The oldest insect fossil is between 408 and 438 million years old. The oldest winged fossil dates back 330 million years ago, suggesting that insects were among the first animals to leave the oceans for land during the Devonian Period some 400 million years ago.  Compare that with the beginning of existence of Homo Sapiens about 650,000 years ago.

They are a major destroyer of crops, and their bites often cause both irritation and disease in animals and humans, so they are not without their downside. This however, is not the whole story.  They pollinate plants, control smaller pests, and serve as food for other animals and birds.  Insects too, provide a vital role in an ecosystem, as decomposers.  They consume dead or dying plants, dead animals and animal faeces. 

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But their most important function is helping to recycle organic waste.  Dung beetles do an amazing job of clearing waste from fields, pulling it underground, where it nourishes and fertilises the soil. They pull many times their own weight into the soil, recycling the nutrients of the dung.

Insects are vital to every ecosystem. They pollinate plants – it is estimated that 80% of trees are pollinated by insects, decompose animal and plant matter, and are themselves a source of food. Birds alone are estimated to eat 400 to 500 million tons of insects per year. Lizards, bats, toads find nourishment in insects.

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Some maggots, the larvae of some flies, have been used since Napoleonic times to clean wounds. The maggots not only eat the dead tissue, but they also secrete ammonia and calcium carbonate, which disinfects the wound. 

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Farmers see them as a pest and use pesticides to destroy them.  It is estimated that due to the heavy use of pesticides, the small bird population has declined by 40% in recent years.  Good news for farmers, perhaps.  From our planet’s point of view, which encompasses all life on the planet, definitely a disaster.  House Sparrows, Starlings and Skylarks are some of the worst-affected birds. But the overall picture for birds is just as serious – since 1980, one out of every six birds has been lost. That adds up to the loss of 600 million breeding birds over 40 years, according to a 2021 study from the RSPB, BirdLife International.

Intensive agriculture, particularly an increase in pesticides and fertiliser use, found to be the main pressure behind most bird population declines. (Ness Amaral-Rogers. 2023).

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An interesting experiment was carried out by the RSPB, who purchased Hope Farm in Cambridgeshire, in 2000. The adoption of nature friendly practices, without insecticide, has resulted in an increase of 177%.  Butterfly numbers have increased by 398%.

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Finally, there is currently work being done (Journal of Bioresource Management, 2021) on the role of insects to biodegrade nano plastics in the soil, an increasing and serious problem arising in the modern world.  Tiny insects can help to put right some of the damage being done by humans.

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The Beginnings of Life on Earth - click here

The First Big Advance - Cyanobacteria, click here

Fabulous Fungi - click here

Vegetation - click here

Earthworms - click here

Birds - click here

Mammals - including humans, click here

Water based life - click here

The Calculus - click here

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