Plot Twist: We're Probably Way Undercounting Insects on Earth

In one sentence: Short Wave's biweekly science news roundup, hosted by Regina Barber and Nate Rott with guest host Scott Detrow (NPR's All Things Considered), covers three stories: Earth's insect species count may be up to three times higher than previously believed, the Euclid space telescope has found 31 ancient quasars, and California's wolf packs are eating mostly cattle instead of wild game.

Story one: Earth's insect species count may be way undercounted

Core findings: The study starts in a protected area in Costa Rica, focused on parasitoid wasps — tiny, millimeter-scale wasps that lay their eggs in or on other species, like caterpillars. Melissa Guzman, an entomologist at Cornell University, is part of the team. Because the wasps are so small that it's hard to tell one species from another by sight, the scientists sequenced a specific stretch of DNA and used modeling to estimate 3,400 different species of just one subfamily of parasitoid wasps in that one nature reserve. They then extended the same modeling approach to a larger insect sample from the reserve to estimate a global total. The prior best estimate — based on studies of beetles — was roughly 6 million insect species (for perspective, even the most generous bird-species estimates put birds at only about 20,000). The new study, published this week in the Proceedings of the National Academy of Sciences (PNAS), concludes that the 6 million figure is a huge undercount: the real number is at least 14 to 20 million — up to three times as many species as previously believed. So far, only about 1 million insects have been taxonomically described. Guzman: "There's so much that we don't know, right? And I think it's humbling, just to get a sense of how much we have yet to discover."

Science background: Species censuses lean on groups that are relatively easy to identify and count, like birds or beetles — but most insects are tiny and look alike, so traditional morphology-based classification basically breaks down on a group as diverse and visually uniform as parasitoid wasps. That's why researchers are turning to DNA barcoding plus statistical modeling: take a measurable small sample (one reserve, one subfamily) and extrapolate to a global total. Rott notes there's "a lot of uncertainty with this kind of modeling," and verifying the new estimate would take a lot more taxonomic work.

Story two: Euclid space telescope finds 31 ancient quasars

Core findings: Quasars are blazing, bright centers of galaxies, powered by a supermassive black hole millions to billions of times the mass of the sun [transcribed as-is: Barber's actual words were "millions of billions of times the mass of our sun" — an order of magnitude larger than the standard astrophysical description of "millions to billions"; likely a verbal slip, reproduced here verbatim per data-fidelity rules] as infalling dust and gas heats up and glows. First author Daming Yang describes it as "a supermassive black hole caught in the act of feeding." The study, out this week in the journal Astronomy and Astrophysics, reports the discovery of 31 quasars, among the oldest ever found — before this study, astronomers only knew a handful of quasars this old. All were found using Euclid, a space telescope launched by the European Space Agency in 2023; it isn't as powerful as Hubble or James Webb, but it was designed to scan large swaths of the sky, which makes it especially good at finding rare objects. These quasars date to soon after the Big Bang and are much bigger and brighter than astronomers would expect that early in the universe's history — the open question, per Yang, is "what are they grown from? How did they grow?" Ancient quasars like these might also tell scientists more about the era when stars were born from the "primordial hot goo" (Rott's informal phrase) that followed the Big Bang.

Science background: A quasar is essentially the extreme, early-universe form of an active galactic nucleus — the bigger the black hole and the more violent the accretion, the brighter the radiation. The older (i.e., earlier in cosmic history) a supermassive quasar is, the harder it is to explain with current models of black hole formation and growth — which is exactly why the episode keeps circling back to "how did they get so big so fast."

Story three: California wolves are mostly eating cattle

Core findings: A new study out this week in the journal PLOS One looks at wolves that migrated into California from Oregon, and their impact on cattle — and consequently on ranchers. UC Davis researchers ran DNA analysis on scat from two wolf packs in 2022 and 2023 to determine diet; both years, the primary food source for these packs was cattle. Lead author Tina Saitone says livestock being the primary food source is uncommon for wolves — in most states, wolves predominantly eat wild game — but "when wolves come to a human-dominated landscape, like California, with very little prey, you're going to see a very different composition of prey." California doesn't have the elk populations of Montana or Wyoming, nor the deer numbers of the Midwest or Northwest. per Barber, Neil Carter — who studies wolves at the University of Michigan and wasn't involved in the study — says this study underscores how complicated it is for carnivores to come back to places that have fundamentally changed; Carter himself, on camera: "if you want to have these animals on the landscape, you know, you have to start kind of building back the full ecosystem." Rott adds that in California this would mean boosting declining mule deer populations (hurt by habitat loss) and other game species like elk — not something that happens overnight, but a target for wildlife managers who want fewer wolf-human conflicts.

Science background: Whether wolves prey on livestock depends heavily on how much wild prey is locally available. When native prey (deer, elk) is scarce because of habitat loss, livestock effectively becomes wolves' fallback food source — which is the ecological root of the conflict between ranchers and returning wolf populations.

Notable details and trivia

• Both Barber and Detrow named the firefly as their favorite insect — independently. Barber says she never saw fireflies on the West Coast until she moved to the East Coast; Detrow joked, "Let's get firefly tattoos."
• Barber called quasars "really, really old fireflies" as a segue linking the insect and quasar stories.
• Detrow described watching a wasp parasitize a cicada in his backyard: "It was like Alien in real life... it blew my mind." Rott quipped "life finds a way"; Barber reassured him these wasps aren't hatching out of human chests.
• Detrow's pre-segment guess for the global insect species count was "4 million" — Rott: "Well, you didn't go over. I'll give you that."
• Production credits: produced by Rachel Carlson and Jordan-Marie Smith; edited by Rebecca Ramirez and Christopher Intagliata; fact-checked by Tyler Jones; audio engineered by Annlie Huang and Tiffany Vera-Castro. Scott Detrow normally hosts NPR's Consider This; the hosts joked they'd get back to "real" space news next week.

Cross-domain connections

None found. This episode's three stories (insect species census, early-universe quasars, California wolf-cattle conflict) have no substantive connection to the acquired business domain. This is also the first Tier 1 extraction in the science domain, so there are no other science episodes yet to cross-reference.

Pages worth building

• euclid-space-telescope (ESA space telescope launched 2023, used here to find ancient quasars; likely to recur in future Short Wave space coverage, worth tracking across episodes)

Source · shortwave