February 11, 2019

Small but vital | Rainforest insect populations are collapsing

Humanity has wiped out 60% of mammals, birds, fish and reptiles since 19701. But this terrifying statistic ignores the invertebrates. This army of insects makes up over two-thirds of terrestrial species and supports every living thing.

Insects are not just declining, they’re being decimated.

More than 40% of insect species are declining and a third are endangered. According to new research, the rate of extinction is eight times faster than that of mammals, birds and reptiles. The total mass of insects is falling by a precipitous 2.5% a year, according to the best data available, suggesting they could vanish within a century.

The biggest threats are from habitat loss, chemicals and climate change. Invertebrates are particularly sensitive to climate change-related variations. They’re unable to regulate their temperatures or migrate to alternative habitats, and they are vulnerable to invasive species 2.  New research has shown that heatwaves can damage the reproductivity of male insects, making them almost sterile 4.

Image of a bee and a thistle plant taken from Unsplash by Olga Brajnovic

Ants cutting leaves and carrying them back to the nest

Insect populations are collapsing as we create an increasingly inhospitable world through deforestation, changing land use and liberal pesticide usage. Humans tend to choose which species to prioritise and save based on usefulness, beauty and visibility. This leaves the ugly bugs, the tiny worms, and the seemingly irritating flies to be lost without trace.

Yet they are the ones that can have the biggest impacts on society and food webs.

hummingbird on branch

Rainforest insects are already being eradicated by habitat loss and climate change.

This is already leading to the collapse of the tropical-forest food web. Recent research 3 has found that the biomass of insects living in the Luquillo rainforest, Puerto Rico has fallen between 10-60 times from what it was in the 1970s. The knock on effects are stark. “Our analyses revealed synchronous declines in the lizards, frogs, and birds that eat arthropods,” the scientists write. “If supported by further research, the impact of climate change on tropical ecosystems may be much greater than currently anticipated.” When insects go, so does everything else.


October’s IPCC Emissions Report demanded urgent action to mitigate the disastrous effects of climate change on biodiversity and the rainforest itself.

Ecological breakdown is a global emergency, and we must respond accordingly. Nature is not ‘nice to have’ – it’s our life support system. We need to treat it as so, big and small, unforgettable or ugly.



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