Insects Suffer Mass Decline With Disturbing Implications For The Ecosystem

Bees and other flying insects are suffering a staggering decline, as 2/3rds of them have disappeared in the last three decades. Photo: Shutterstock

Most people aren’t fans of insects, so to many people if insects suddenly disappeared it would seem like a good thing. In fact, this very phenomenon was discovered in Germany recently, but rather than rejoicing, many scientists are worried about the situation.

A new study done on insect populations in Germany, and published in the journal Plos One, has discovered that almost three-quarters of Germany’s flying insects have disappeared over the last three decades, a blink of an eye in the history of our planet. The sudden disappearance of these insects has scientists worried about a possible ecological collapse.

Flying insects, and insects, in general, are an integral part of our ecosystem. According to estimates by scientists, around 80% of all wild plants need insects for pollination. Many of the plants that require insects for pollination produce fruits and vegetables for us to eat. Around 60% of birds use insects for food as well.

A Drop of Two-Thirds

Professor Dave Goulson of Sussex University explains that insects make up approximately two-thirds of all life on Earth, but that there has been a “horrific decline” in insects just recently.

“We appear to be making vast tracts of land inhospitable to most forms of life and are currently on course for ecological Armageddon. If we lose the insects then everything is going to collapse,” says Goulson.

The recent report in Plos One was the result of a 27-year long study, running from 1989 to 2016, that tracked insect levels at 63 different nature reserves all across Germany. Researchers measured insects levels with something called a malaise trap, a tent that captures insects and puts them into containers without harming them.

Over the duration of the 27-year long study, the yearly biomass of flying insects was cut by three quarters.  The effect was most pronounced in the summer months. During the summer insect populations should be most abundant, and the average number of insects was 82% percent lower than expected.

Though the research was only done on insect populations in Germany, the researchers believe that the study is likely to be representative of a trend around the entire globe.

The Scope of the Problem

Certain populations of insects have been known to be in decline for a while now, as both certain bees and butterflies have been observed to be mysteriously on the decline. However, this is the first time that such large-scale research has been over such a long period of time. The research was also conducted in well-managed nature preserves, potentially meaning that elsewhere the phenomenon could be even worse.

There are at least a few different reasons why insects may suddenly be disappearing. Among the primary suspects are pesticides that cause habitat loss and global warming.

Detailed records about the weather were noted, along with any changes to the landscape of the preserves or changes to plants in the preserve. These factors did not explain the sudden loss of insect species. While the weather might impact insect populations in a given year, it doesn’t explain the drastic downward trend over the past three decades.

Pesticides are often applied to entire landscapes. Photo: David R Frazier Photolibrary/Alamy

Goulson says it is possible that something about the environment is killing insects when they leave nature preserves. Goulson says that farmland has cannot sustain most wild creatures, insects included. What is killing them is open for debate, but it could be a combination of pesticide use and a lack of the foods traditionally eaten by insects.

This past September the UK’s chief scientific advisers, Ian Boyd and Alice Milner, warned that the assumption that pesticides are safe to use at massive industrial scales across entire landscapes is false. Boyd says that the impacts of whole landscape dosing with pesticides have been ignored by regulatory bodies and that the required research and monitoring for the effects of wide-scale pesticide use does not yet exist.

Milner explains that controlling the distribution of pesticides is extremely hard and that any chemical you put out into the environment can be widely distributed.

“We’ve known this [about pesticides dispersing] for decades, particularly through the early work in the 1960s – the Silent Spring, DDT and so on – and you can find chemicals in places that have not been treated because of the connectivity of ecosystems,” says Milner. “There are often quite unexpected effects [and] you often don’t see them until the pesticide is used at more industrial scales.”

An Unseen Problem

If it seems like the massive loss of insect species is just being recognized as a problem, it may be for two different reasons. The first reason is cultural, people simply tend to care less about the lives of insects over the lives of vertebrates, with the possible exception of butterflies and bees. In general, people dislike insects and wouldn’t mind it if many disappeared.

There is a second reason that the problem is only recently being brought to light, the sheer amount of insect species. Monitoring the status of even a fraction of a percent of all insect species is almost impossible. For instance, the UK by itself is home to 24,500 insect species, and these are only the known ones. The massive amount of species means that even if insects were experiencing a dramatic decline, the problem was imperceptible to us until very recently.

Insects are necessary not only for pollination but for feeding birds and other animals. Photo: Kevin Elsby/Alamy

Researchers like Lynn Dicks from the University of East Anglia, UK, say the new study is convincing and extremely alarming, full of negative implications for the health of the ecosystem as a whole. Dicks notes that flying insects play extremely important roles in ecosystems. Moths, butterflies, bees, and flies pollinate flowers. Insects provide food for animals like bats, birds, fish, and amphibians. They also help clean up detritus and act as decomposers.

While it will be sometime before the full impact of the problem is realized, some of the impacts of insect die-off may be viewable right now. A different study also conducted in Germany found that the number of birds in the country has also been declining rapidly. In the past 12 years, around 12.5 million pairs of breeding birds have gone missing. That’s approximately 15% of the overall bird population in Germany. While no research has been done to establish a link between the two shrinking populations, it does seem unlikely that the two phenomena are not related.

More research will have to be done, both to corroborate the findings of this report and to uncover the cause of insect die-off. More research can help us determine what is killing insects and take actions to address the problem.

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