Global insect population faces “catastrophic” collapse – “If we destroy the basis of the ecosystem, which are the insects, then we destroy all the other animals that rely on them for a food source”

Desdemona Despair

12 February 2019 (University of Sydney) – A research review into the decline of insect populations has revealed a catastrophic threat exists to 40 percent of species over the next 100 years, with butterflies, moths, dragonflies, bees, ants, and dung beetles most at risk.

Author of the review, Dr Francisco Sanchez-Bayo, an honorary associate with the Sydney Institute of Agriculture in the School of Life and Environmental Sciences, said that habitat loss from intensive agriculture alongside agro-chemical pollutants, invasive species and climate change are the main drivers behind the collapse in insect populations.

“As insects comprise about two thirds of all terrestrial species on Earth, the trends confirm that the sixth major extinction event is profoundly impacting life forms on our planet,” write Dr Sanchez-Bayo and co-author Dr Kris Wyckhuys from the University of Queensland and the Institute of Plant Protection, China Academy of Agricultural Sciences, Beijing.

Their study was published this week in Biological Conservation. It involved a comprehensive review of 73 historical reports of insect declines from across the globe, systematically assessing the underlying drivers of the population declines.

“Because insects constitute the world’s most abundant animal group and provide critical services within ecosystems, such an event cannot be ignored and should prompt decisive action to avert a catastrophic collapse of nature’s ecosystems,” the report said.

“We are realists”

Speaking to ABC television in Australia, Dr Sanchez-Bayo said: “We are not alarmists, we are realists. We are experiencing the sixth mass extinction on Earth. If we destroy the basis of the ecosystem, which are the insects, then we destroy all the other animals that rely on them for a food source.

“It will collapse altogether and that’s why we think it’s not dramatic, it’s a reality.”

To address this threat to insect species, the study said humanity needs to rethink “current agricultural practices, in particular a serious reduction in pesticide usage and its substitution with more sustainable, ecologically based practices”.

Dr Sanchez-Bayo said this is urgently needed to slow or reverse these current trends to “allow the recovering of declining insect populations and safeguard the vital ecosystem services they provide”.

Impact could be “unimaginable”

Dr Tanya Latty is also from the Sydney Institute for Agriculture and works in the Social Insects Lab in the School of Life and Environmental Sciences. She was not connected to the Biological Conservation study.

Dr Latty said: “Insects are absolutely vital to our ecosystems: they are pollinators, pest controllers and waste managers. They are food to countless birds, reptiles, mammals and fish. Left unchecked, the ongoing loss of insects will impact our daily lives in ways that are almost unimaginable.

“Insects are resilient and it’s not too late to stop and even reverse declines. But we need to care enough to do something. I hope Dr Sanchez-Bayo’s study gets people to stand up and take notice of what we are losing – and what can still be saved.”

Reporting of the research has gone global, with reports by the BBC, CNN, The Huffington Post, Al Jazeera, El Pais, the New York Post, New Scientist and many others. The Guardian in London, which broke the story, has also penned an editorial on the subject.

Social media was also lit up, with people expressing dismay at the conclusions of the study.

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Insect population faces ‘catastrophic’ collapse: Sydney research

ABSTRACT: Biodiversity of insects is threatened worldwide. Here, we present a comprehensive review of 73 historical reports of insect declines from across the globe, and systematically assess the underlying drivers. Our work reveals dramatic rates of decline that may lead to the extinction of 40% of the world’s insect species over the next few decades. In terrestrial ecosystems, Lepidoptera, Hymenoptera and dung beetles (Coleoptera) appear to be the taxa most affected, whereas four major aquatic taxa (Odonata, Plecoptera, Trichoptera, and Ephemeroptera) have already lost a considerable proportion of species. Affected insect groups not only include specialists that occupy particular ecological niches, but also many common and generalist species. Concurrently, the abundance of a small number of species is increasing; these are all adaptable, generalist species that are occupying the vacant niches left by the ones declining. Among aquatic insects, habitat and dietary generalists, and pollutant-tolerant species are replacing the large biodiversity losses experienced in waters within agricultural and urban settings. The main drivers of species declines appear to be in order of importance: i) habitat loss and conversion to intensive agriculture and urbanisation; ii) pollution, mainly that by synthetic pesticides and fertilisers; iii) biological factors, including pathogens and introduced species; and iv) climate change. The latter factor is particularly important in tropical regions, but only affects a minority of species in colder climes and mountain settings of temperate zones. A rethinking of current agricultural practices, 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. In addition, effective remediation technologies should be applied to clean polluted waters in both agricultural and urban environments.

Worldwide decline of the entomofauna: A review of its drivers