Opinion: Insect decline worries scientists

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MICHELE S. BYERS / NJ CONSERVATION FOUNDATION – Of all the creatures in the animal kingdom, insects are the least loved.

Anyone who’s been bitten by ticks, stung by bees, swarmed by mosquitos, bothered by flies or had ants crash their picnic – in other words, everyone – has, at some point, wondered if the world would be better without bugs.

But be careful of what you wish for! A world without bugs would be uninhabitable for most species.

Insects pollinate plants, including crops, control pests and reduce waste. They’re at the bottom of the wildlife food chain and are essential for the survival of birds, reptiles, amphibians, fish and mammals – and humans!

Unfortunately, scientists around the globe are noticing an alarming decline in the number and variety of insects.

Most recently, a long-term study of 63 nature reserves in northwestern Germany showed “dramatic” declines in insect populations.  Published in the online science journal PLOS One in 2017, the study found that flying insect populations declined by more than 75 percent from 1989 to 2016.

“The flying insect community as a whole … has been decimated over the last few decades,” according to the study, conducted by researchers from Radboud University in the Netherlands and the Entomological Society Krefeld in Germany. “Loss of insect diversity and abundance is expected to provoke cascading effects on food webs and to jeopardize ecosystem services.”

Scientists captured flying insects in traps made of netting to collect data on insect “biomass.”  While researchers found a seasonal average 75 percent decline in insect biomass, they found even higher rates of decline – up to 82 percent – in the midsummer period when insect numbers usually peak.

Researchers said climate change, habitat loss and fragmentation, and deterioration of habitat are prime suspects responsible for the decline. They also theorized that pesticide use on surrounding agricultural lands another could be another cause, but said further study is needed.

“There is an urgent need to uncover the causes of this decline, its geographical extent, and to understand the ramifications of the decline for ecosystems and ecosystem services,” the study concluded.

If these German nature reserves – whose very purpose is to protect a rich diversity of flora and fauna – are experiencing such a dramatic loss of insects, are similar declines occurring in other places in Germany and around the world?

The German study cited an American report showing that ecosystem services provided by wild insects in the United States are worth an estimated $57 billion a year. Some 80 percent of wild plants rely on insects for pollination, and 60 percent of birds depend on insects as a food source. “Clearly, preserving insect abundance and diversity should constitute a prime conservation priority,” the study said.

Edward O. Wilson, the distinguished Harvard biologist and author, once described insects as “the little things that run the world.”  By his calculations, they’re more important than humans in the grand scheme. “If all humankind were to disappear, the world would regenerate back to the rich state of equilibrium that existed 10,000 years ago,” he wrote. “If insects were to vanish, the environment would collapse into chaos.”

As the German study suggests, more research is needed on the potential causes of insect decline – and steps that can be taken to reverse it. Our insects are far too important to lose!

To learn more about the German study, go to https://journals.plos.org/ plosone/article?id=10.1371/ journal.pone.0185809

For a report on how neonicotinoid pesticides are affecting insects, go to www.iucn.org/news/secretariat/ 201709/severe-threats- biodiversity-neonicotinoid- pesticides-revealed-latest-scientific-review.

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