Imagine a world without insects. You might breathe a sigh of relief at the thought of mosquito-free summers, or you might worry about how agriculture will function without pollinators. What you probably won’t picture is trudging through a landscape littered with feces and rotting corpses — what a world devoid of maggots and dung beetles would look like.

That’s just a snippet of the horrifying picture of an insect-free future that journalist Oliver Milman paints in the beginning of The Insect Crisis. “The loss of insects would be an agonizing ordeal eclipsing any war and even rivaling the looming ravages of climate breakdown,” he writes. And yet, the threat of an impending “insect apocalypse” doesn’t get nearly the same level of attention as climate change.

Researchers have been observing declining insect populations for decades. For instance, a study of nearly 40 years of data from a protected rainforest in Puerto Rico found that insect biomass had decreased by 98 percent on the ground and 80 percent in the canopy since the mid-1970s.

The threats insects face are many: Light pollution, the increasing use of pesticides and climate change are just a few (SN: 8/31/21; SN: 8/17/16; SN: 7/9/15). And it’s not only rare species that are at risk — it’s also species that were once common around the globe.

The reality of the crisis isn’t as foreboding as Milman initially makes it seem. A world with no insects is unlikely, he acknowledges. Studies have found that while some species are in decline, others, such as freshwater insects, are doing fine (SN: 4/23/20). Rather than viewing the insect crisis as all insect populations on one downward-trending line on a graph, Milman suggests picturing lots of different lines — some holding steady, some sloping up or down, and some zigzagging. “Insects are being shifted to an unhappy state where there will be far more bedbugs and mosquitoes and far fewer bumblebees and monarch butterflies,” he writes.

Those changes in biodiversity come with consequences. Farmers may have to fend off more pests that attack soybeans, for instance, and insect-pollinated fruits and vegetables will become hard to grow at scale. Some insect-eating animals will decline as their food disappears, which has already happened to some birds (SN: 7/11/14), or even vanish. Water and soil quality could also be in jeopardy.
Milman investigates the crisis by sharing his own adventures with insects, along with those of researchers, taking readers from the United States to Mexico, across the Atlantic to Europe and all the way to Australia. By sharing scientists’ stories, he makes the plight of insects personal. There’s a researcher in Denmark who has spent 25 years surveying insect populations by driving his old Ford Anglia down the same country roads and counting the number of bugs squashed against the windshield. Back when he started, he’d regularly have to clean insect guts off his car. But in recent years, he has experienced a lot of “zero insect days.” As I read that, I struggled to remember the last time I had to scrape any dead insects off my car. Another researcher recalls the joy of catching fireflies on his family ranch in Texas as a child. I felt a wave of sadness as I thought about how I don’t see fireflies as much as I did when I was a kid. With more streetlights and the switch to LED bulbs, it’s becoming harder for fireflies to spot potential mates.

Amid the doom and gloom, the book still manages to spark awe and delight with fun facts about insects. Bumblebee wings, for instance, vibrate so fast that they can produce gravitational forces of up to 50 g’s — five times greater than what fighter jet pilots experience. Milman also offers hope, sharing how certain insects are adapting to the threats and how some people are fighting to protect the critters through political campaigns and changing farming habits.

By the book’s end, readers may find that their attitude toward some insects has shifted from loathing to love, or at the very least, appreciation. (I, for one, never cared much for flies — until I learned we wouldn’t have chocolate without them.) Milman makes clear how much we benefit from insects, and what we stand to lose without them. As one researcher puts it, our deeply woven reliance on insects is like the internet: When parts of the network are removed, the less internet there is, “until eventually it doesn’t work anymore.”

A world without the internet would be difficult but livable. The same can’t be said for a world without insects.

More of the ingredients for life have been found in meteorites.

Space rocks that fell to Earth within the last century contain the five bases that store information in DNA and RNA, scientists report April 26 in Nature Communications.

These “nucleobases” — adenine, guanine, cytosine, thymine and uracil — combine with sugars and phosphates to make up the genetic code of all life on Earth. Whether these basic ingredients for life first came from space or instead formed in a warm soup of earthly chemistry is still not known (SN: 9/24/20). But the discovery adds to evidence that suggests life’s precursors originally came from space, the researchers say.
Scientists have detected bits of adenine, guanine and other organic compounds in meteorites since the 1960s (SN: 8/10/11, SN: 12/4/20). Researchers have also seen hints of uracil, but cytosine and thymine remained elusive, until now.

“We’ve completed the set of all the bases found in DNA and RNA and life on Earth, and they’re present in meteorites,” says astrochemist Daniel Glavin of NASA’s Goddard Space Flight Center in Greenbelt, Md.

A few years ago, geochemist Yasuhiro Oba of Hokkaido University in Sapporo, Japan, and colleagues came up with a technique to gently extract and separate different chemical compounds in liquified meteorite dust and then analyze them.

“Our detection method has orders of magnitude higher sensitivity than that applied in previous studies,” Oba says. Three years ago, the researchers used this same technique to discover ribose, a sugar needed for life, in three meteorites (SN: 11/22/19).

In the new study, Oba and colleagues combined forces with astrochemists at NASA to analyze one of those three meteorite samples and three additional ones, looking for another type of crucial ingredient for life: nucleobases.

The researchers think their milder extraction technique, which uses cold water instead of the usual acid, keeps the compounds intact. “We’re finding this extraction approach is very amenable for these fragile nucleobases,” Glavin says. “It’s more like a cold brew, rather than making hot tea.”

With this technique, Glavin, Oba and their colleagues measured the abundances of the bases and other compounds related to life in four samples from meteorites that fell decades ago in Australia, Kentucky and British Columbia. In all four, the team detected and measured adenine, guanine, cytosine, uracil, thymine, several compounds related to those bases and a few amino acids.

Using the same technique, the team also measured chemical abundances within soil collected from the Australia site and then compared the measured meteorite values with that of the soil. For some detected compounds, the meteorite values were greater than the surrounding soil, which suggests that the compounds came to Earth in these rocks.

But for other detected compounds, including cytosine and uracil, the soil abundances are as much as 20 times as high as in the meteorites. That could point to earthly contamination, says cosmochemist Michael Callahan of Boise State University in Idaho.

“I think [the researchers] positively identified these compounds,” Callahan says. But “they didn’t present enough compelling data to convince me that they’re truly extraterrestrial.” Callahan previously worked at NASA and collaborated with Glavin and others to measure organic materials in meteorites.

But Glavin and his colleagues point to a few specific detected chemicals to support the hypothesis of an interplanetary origin. In the new analysis, the researchers measured more than a dozen other life-related compounds, including isomers of the nucleobases, Glavin says. Isomers have the same chemical formulas as their associated bases, but their ingredients are organized differently. The team found some of those isomers in the meteorites but not in the soil. “If there had been contamination from the soil, we should have seen those isomers in the soil as well. And we didn’t,” he says.

Going directly to the source of such meteorites — pristine asteroids — could clear up the matter. Oba and colleagues are already using their extraction technique on pieces from the surface of the asteroid Ryugu, which Japan’s Hayabusa2 mission brought to Earth in late 2020 (SN: 12/7/20). NASA’s OSIRIS-REx mission is expected to return in September 2023 with similar samples from the asteroid Bennu (SN: 1/15/19).

“We’re really excited about what stories those materials have to tell,” Glavin says.