The number of flying insects has dropped by up to 75% in less than 30 years, provoking the risk of an "ecological Armageddon", scientists have said.
Research stretching over 63 protected areas in Germany and dating back to 1989 provides a frightening view of ecological change – with implications across the globe.
It showed an average annual decline of 76% over the course of the study, and as much as 82% in mid-summer.
The study was published in the peer-reviewed journal Plos One and warned the "loss of insect diversity and abundance is expected to provoke cascading effects on food webs and to jeopardise ecosystem services."
Populations of insects are vital as pollinators and prey for other creatures.
The study suggests that an entire community of flying insects, including butterflies, bees, and moths, has been "decimated", researchers said.
Scientists had been aware of the decline in the number of insects – which they describe as "the windscreen phenomenon", where there seem to be fewer squashed insects on car windows than there was in the past.
But this study suggests a sharper decline than previously thought.
Professor Dave Goulson at the University of Sussex, one of the co-authors of the report, said: "Insects make up about two thirds of all life on Earth.
"We appear to be making vast tracts of land inhospitable to most forms of life, and are currently on course for ecological Armageddon.
"On current trajectory, our grandchildren will inherit a profoundly impoverished world."
The new data has shocked the amateur entomologists, who used special tents called malaise traps to capture the creatures across nature reserves in Germany.
Another researcher, Hans de Kroon of Radboud University, said the study "places the decline of insect-eating birds and mammals in a new context".
He added: "We need to do less of the things that we know have a negative impact, such as the use of pesticides."