Bugs are critical to the global environment — they facilitate the pollination of crops and flowers, decompose waste, support food chains, and much more.
Without them, whole ecosystems could collapse. Yet that’s what’s happening. All around the world, insect populations are plummeting, according to the Washington Post, and entomologists — insect experts — are panicking.
The latest report documenting this decline, published in the Proceedings of the National Academy of Sciences, focuses on insects in Puerto Rico’s rainforests.
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The lead researcher, Bradford Lister of Rensselaer Polytechnic Institute, has been tracking insects for decades with his team through a sophisticated system of nets and traps. During this time, they noticed a growing decline in various populations.
In 2013, insect catch rates in the nets dropped to an eighth of what they were in 1977 and catch rates in the traps fell 60-fold.
Lister told the Post that climate change is the most likely culprit because average peak temperatures in the rainforests have risen by 4 degrees Fahrenheit over the past four decades and the insects being studied are sensitive to climate.
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Pesticides can likely be ruled out as a cause in this instance because their use has fallen by 80% in Puerto Rico during this time.
In addition to a decline in insects, the researchers also found that insect-eating animals such as lizards were vanishing, too, signaling a food chain breakdown.
“This study in PNAS is a real wake-up call — a clarion call — that the phenomenon could be much, much bigger, and across many more ecosystems,” David Wagner, an expert in invertebrate conservation at the University of Connecticut, told the Post. “This is one of the most disturbing articles I have ever read.”
The data adds to a growing body of research showing how insects are struggling to survive in the face of disappearing habitats, global warming, climate change, an explosion of pesticide use, and more.
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A report from 2014 found that invertebrate populations had decreased by 45% over the preceding 35 years and a report from last year found that flying insects had fallen by 76% in Germany.
In various countries, key crop pollinators such as butterflies and bees are declining. Meanwhile crop-ravaging insects are proliferating and expanding their ranges amid higher temperatures.
Another forward-looking report determined that insects will suffer the largest habitat losses if climate changes continues to intensify.
And the analysis of rainforests in Puerto Rico shows, other animals tend to follow the lead of insects.
“If the tropical forests go it will be yet another catastrophic failure of the whole Earth system,” Liste, the author of the report, told the Post. “That will feed back on human beings in an almost unimaginable way.”