A sweeping review of 73 scientific studies around the world has painted a dire picture of mass insect extinction over the next few decades that would have "catastrophic" effects on the planet.

The analysis, titled "Worldwide Decline of the Entomofauna: A Review of Its Drivers" was published in the journal Biological Conservation.

The study warns that more than 40 percent of the world's insect species are at risk of extinction, and a third are endangered.

The authors said the decline likely stems from factors including habitat loss, invasive species, pollution from pesticides and fertilizers, as well as climate change.

"A rethinking of current agricultural practices," the study's authors write, "in particular a serious reduction in pesticide usage and its substitution with more sustainable, ecologically-based practices, is urgently needed to slow or reverse current trends, allow the recovery of declining insect populations and safeguard the vital ecosystem services they provide."

The study was co-authored by researchers from the universities of Sydney and Queensland and the China Academy of Agricultural Sciences.

The authors noted that the world is currently in the throes of the largest extinction event since the late Permian period 252 million years ago and the Cretaceous period 66 million years ago.

A study last year found that the number of flying insects in German nature reserves dropped by more than 75 percent over a 27-year span, suggesting the collapse of insect populations extends outside areas directly affected by habitat loss and agricultural pollution.

Read More:

• Plummeting Insect Numbers 'Threaten Collapse Of Nature' (The Guardian)
• Daily Briefing: Insect Decline Threatens "Catastrophic Collapse Of Nature's Ecosystems" (Nature)