Somehow, it's easier to worry about wolves, sea turtles, and white rhinos dying off than it is to feel remorse over vanishing bugs.
But the loss of insects is a dire threat – one that could trigger a "catastrophic collapse of Earth's ecosystems," a new study said.
The research, the first global review of its kind, looked at 73 historical reports on insect declines around the world and found the total mass of all insects on the planets decreasing by 2.5% per year.
If this trend continues unabated, Earth may not have any insects at all by 2119.
"In 10 years you will have a quarter less, in 50 years only half left and in 1
That's a big problem because insects are food sources for countless birds, fish, and mammal species. Pollinators such as bees and butterflies also play a crucial role in fruit, vegetable, and nut production.
Sanchez-Bayo and his coauthors have focused their analysis on insects in European and North American countries. They estimate that 41% of insect species are in decline, and 31% are threatened (according to criteria set by the International Union for Conservation of Nature), and 10% are going locally extinct.
That extinction rate is eight times faster than the observed rate of extinction for mammals, birds, and reptiles.
The study suggested that bee species in the UK, Denmark, and North America have taken major hits – bumblebees, honey bees, and wild bee species are all declining. In the US, the number of honey-bee colonies dropped from 6 million in 1947 to 2.5 million just six decades later.
Dragonflies, mayflies, and beetles seem to be dying off as well.
According to a 2017 study, Earth looks to be undergoing a process of "biological annihilation." That analysis estimated that "as much as 50% of the number of animal individuals that once shared Earth with us are gone."
This rapid decline in global biodiversity is sometimes called the "sixth extinction," since it's the sixth time in the history of life on Earth that the planet's fauna has experienced a major collapse in numbers.
In the past, mass extinctions have been caused by the emergence of ice ages or asteroid collisions. This mass extinction, however, is driven by human activities – namely, deforestation, mining, and carbon-dioxide emissions that contribute to global warming.
"As insects comprise about two thirds of all terrestrial species on Earth, the above trends confirm that the sixth major extinction event has profoundly impacting life forms on our planet," the authors wrote.
Read more: Scientists say we are witnessing the sixth mass extinction of the planet – and 'biological annihilation' is the latest sign
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The study emphasized that insects are "essential for the proper functioning of all ecosystems" as food sources , crop pollinators, pest controllers, and nutrient recyclers in soil.
"If insect species can not be stopped, this will have catastrophic consequences for both the planet's ecosystems and the survival of mankind," Sanchez-Bayo told The Guardian.
Substantial declines in insect populations therefore threaten the food, timber, and fiber production that humanity's survival depends on, according to Timothy Schowalter, professor of entomology at Louisiana State University.
"The pollinator declines 35% of our global food supply, which is why European countries are mandating to protect and restore pollinator habitats," he told Business Insider.
Schowalter added that insects are also critical food resources for many birds, fish and other vertebrates, which would disappear if their food sources do.
"Insects are often maligned, or at least their significant contribution to ecosystem productivity and delivery of ecosystem services are underappreciated," Schowalter said. "In short, if insects and other arthropods are declining, our survival would be threatened."
This is not the first time scientists have called attention to plummeting insect populations.
In 2017, a study indicated that 75% of Germany's flying insects had disappeared since the 1990s. Another recent study has shown that the total biomass of arthropods – creatures such as insects, spiders, and lobsters that have jointed legs but no backbone – in Puerto Rico has taken a nose dive since the 1970s.
Pesticides, fertilizers, and heavy land use are primary drivers of this decline.
"Overall, the systematic, widespread and often superfluous use of pesticides in agricultural and pasture land over the past 60 years has negatively impacted most organisms, from insects to birds and bats," the authors of the new study wrote.
They added: "The conclusion is clear: unless we change our ways of producing food, insects as a whole will go down the path of extinction in a few decades."
Sanchez-Bayo told The Guardian he thinks insecticides such as neonicotinoids and fipronil are especially damaging.
"They sterilize the soil, killing all the grubs," he said.
Climate change-driven temperature shifts are also a role in insect deaths, factor.
"So far, declines have been related to land-use changes, especially agricultural intensification, forest fragmentation and urban development, rather than temperature change," Schowalter said.