SAN DIEGO — Labs growing replicas of snakes’ venom glands may one day replace snake farms.
Researchers in the Netherlands have succeeded in growing mimics of venom-producing glands from multiple species of snakes. Stem cell biologist Hans Clevers of the Hubrecht Institute in Utrecht, the Netherlands, reported the creation of these organoids on December 10 at a joint meeting of the American Society for Cell Biology and the European Molecular Biology Organization.
If scientists can extract venom from the lab-grown glands, that venom might be used to create new drugs and antidotes for bites including from snakes that aren’t currently raised on farms.
Up to 2.7 million people worldwide are estimated to be bitten by venomous snakes each year. Between about 81,000 to 138,000 people die as a result of the bite, and as many as roughly 400,000 may lose limbs or have other disabilities, according to the World Health Organization. Antivenoms are made using venom collected from snakes usually raised on farms. Venom is injected into other animals that make antibodies to the toxins. Purified versions of those antibodies can help a bitten person recover, but must be specific to the species of snake that made the bite. “If it’s a fairly rare or local snake, chances are there would be no antidote,” Clevers says.
Three postdoctoral researchers in Clevers’ lab wanted to know if they could make organoids — tissues grown from stem cells to have properties of the organs they mimic — from snakes and other nonmammalian species. The researchers started with Cape coral snakes (Aspidelaps lubricus) that were dissected from eggs just before hatching. Stem cells taken from the unhatched snakes grew into several different types of organoids, including some that make venom closely resembling the snake’s normal venom, Clevers reported at the meeting.
His team has produced venom-gland organoids from at least seven species of snakes. The organoids have survived in the lab for up to two years so far.
Clevers and colleagues hope to harvest venom from the organoids, which produce more highly concentrated venom than snakes usually make. “It’s probably going to be easier than milking a snake,” he says.
Satellites may be a more accurate way to track smog-producing ammonia.
It’s notoriously tricky to pinpoint accurate numbers for ammonia gas emissions from sources such as animal feedlots and fertilizer plants. But new maps, generated from infrared radiation measurements gathered by satellites, reveal global ammonia hot spots in greater detail than before. The new data suggest that previous estimates underestimate the magnitude of these emissions, researchers report December 5 in Nature.
In the atmosphere, ammonia, which contains nitrogen, can help form tiny particles that worsen air quality and harm human health. The research could help keep tabs on who’s emitting how much, to make sure that factories and farms are meeting environmental standards. Emissions are usually estimated by adding up output from individual known sources of activity, but those calculations are only as good as the data that go into them. Ammonia sticks around only hours to a few days in the atmosphere, so on-the-ground measurements vary a lot even in the same place, says coauthor Martin Van Damme, an atmospheric scientist at the Université Libre de Bruxelles in Belgium.
“There’s so much uncertainty in ammonia emissions,” says Daven Henze, a mechanical engineer at the University of Colorado Boulder who wasn’t part of the research. Other scientists, including his research group, have estimated ammonia releases using satellite data before. But these new maps rely on a more detailed dataset and have substantially better resolution, Henze says — fine enough that the study authors were able to link areas of high emissions to specific factories or farms. The new maps show 248 nitrogen emission hot spots across the globe at a resolution of about a kilometer. Eighty-three of those hot spots arose from agricultural activity that involved high numbers of cows, pigs and chickens, such as a site in Colorado that overlapped on satellite imagery maps with two big cattle feedlots. Ammonia emissions from feedlots come largely from livestock waste. Another 158 sites were affected by industrial emissions — mostly from sites that produced ammonia-based fertilizer, such as in Marvdasht, Iran. Six hot spots couldn’t be pinned to specific activity. Ammonia is also emitted naturally, from volcanoes or seabird colonies. But most of those sources were too weak or not concentrated enough to show up as hot spots in the data. Lake Natron in Tanzania is the one exception — its mud flats show up as an ammonia-releasing hot spot, perhaps due to decaying algae. But it’s not clear why other lakes with similar mud flats didn’t. Some natural sources may have gone undetected because of where they were located — in places with heavy cloud cover that obscured the data, or where turbulent air dissipated ammonia especially quickly, Van Damme suggests.
Some areas with particularly high overall ammonia emissions from biomass burning or fertilizer, such as West Africa and the Indus Valley in Pakistan and northern India, didn’t reveal specific hot spots, either, the researchers report.
Since people in the United States began dying in the fentanyl-related drug overdose epidemic, whites have been hit the hardest. But new data released March 21 by the Centers for Disease Control and Prevention show that African-Americans and Hispanics are catching up.
Non-Hispanic whites still experience the majority of deaths involving fentanyl, a synthetic opioid. But among African-Americans and Hispanics, death rates rose faster from 2011 to 2016. Whites experienced a 61 percent annual increase, on average, while the rate rose 140.6 percent annually for blacks and 118.3 percent per year for Hispanics. No reliable data were available for other racial groups. Overall, the number of U.S. fentanyl-related deaths in 2011 and 2012 hovered just above 1,600. A sharp increase began in 2013, reaching 18,335 deaths in 2016. That’s up from 0.5 deaths per 100,000 people in 2011 to 5.9 per 100,000 in 2016.
In the first three years of the data, men and women died from fentanyl-related overdoses at similar rates, around 0.5 per 100,000. But in 2013, those paths diverged, and by 2016, the death rate among men was 8.6 per 100,000; for women it was 3.1 per 100,000. Overdose death rates rose most sharply along the East Coast, including in New England and the middle Atlantic, and in the Great Lakes region.
One of the most powerful opioids, fentanyl has been around for decades and is still prescribed to fight pain. But it has emerged as a street drug that is cheap to make and is found mixed into other drugs. In 2013, fentanyl was the ninth most common drug involved in overdose deaths, according to the CDC report; in 2016, it was number one. Just a little bit can do a lot of damage: The drug can quickly kill a person by overwhelming several systems in the body (SN: 9/3/2016, p. 14).
Viruses, which cannot reproduce on their own, infect cells and usurp their genetic machinery for use in making new viruses…. But just how viruses use the cell machinery is unknown.… Some answers may come from work with an unusual virus, called M13, that has a particularly compatible relationship with … [E. coli] bacteria. — Science News, April 5, 1969
Update M13 did help unlock secrets of viral replication. Some bacteria-infecting viruses, called bacteriophages or simply phages, kill the host cell after hijacking the cell’s machinery to make copies of themselves. Other phages, including M13, leave the cell intact. Scientists are using phage replication to develop drugs and technologies, such as virus-powered batteries (SN: 4/25/09, p. 12). Adding genetic instructions to phage DNA for making certain molecules lets some phages produce antibodies against diseases such as lupus and cancer. The technique, called phage display, garnered an American-British duo the 2018 Nobel Prize in chemistry (SN: 10/27/18, p. 16).
My youngest child, now just over a year old, has started to talk. Even though I’ve experienced this process with my older two, it’s absolutely thrilling. He is putting words to the thoughts that swirl around in his sweet little head, making his mind a little less mysterious to the rest of us.
But these early words may not mean what we think they mean, a new study hints. Unsurprisingly, when 2-year-olds were asked a series of “this or that” questions, the toddlers showed strong preferences — but not for the reasons you’d think. Overwhelmingly, the toddlers answered the questions with the last choice given. That bias, described in PLOS ONE on June 12, suggests that young children’s answers to these sorts of questions don’t actually reflect their desires. Instead, kids may simply be echoing the last thing they heard.
This verbal quirk can be used by parents to great effect, as the researchers point out in the title of their paper: “Cake or broccoli?” More fundamentally, the results raise questions about what sort of information a verbal answer actually pulls out of a young child’s mind. This murkiness is especially troublesome when it comes to questions whose answers call for adult action, such as: “Did you hit your sister on purpose or on accident?”
In the first series of experiments, researchers led by Emily Sumner at the University of California, Irvine, asked 24 1- and 2-year-olds a bunch of two-choice questions, some of which involved a polar bear named Rori or a grizzly bear named Quinn. One question, for example, was, “Does Rori live in an igloo or a tepee?” Later, the researchers switched the bear and the order of the options, asking, for example, “Does Quinn live in a tepee or an igloo?”
The toddlers could answer either verbally or, for reluctant speakers, by pointing at one of two stickers that showed the choices. When the children answered the questions by pointing, they chose the second option about half the time, right around chance. But when the toddlers spoke their answers, they chose the second option 85 percent of the time, regardless of the bear. SECOND BEST A toddler taking part in a study selects the second option in three either-or questions. This tendency, called the recency bias, may reflect kids’ inability to juggle several choices in their minds simultaneously. Credit: E. Sumner et al/PLOS ONE 2019
This abundance of second options selected — a habit known as the recency bias — might be due to the fact that young children have trouble holding the first option in mind, the researchers suspect. Other experiments showed that children’s tendency toward the second option got stronger when the words got longer.
Adults actually have the opposite tendency: We’re more inclined to choose the first option we’re given (the primacy bias). To see when this shift from last to first occurs, the researchers studied transcripts of conversations held between adults and children ages 1.5 to 4. In these natural conversations, 2-year-olds were more likely to choose the second option. But 3- and 4-year-olds didn’t show this bias, suggesting that the window closes around then.
The results hold a multitude of delightful parenting hacks: “Would you like to jump on the bed all night, or go to sleep?” But more importantly, the study serves as a reminder that the utterances of small children, while fascinating, may not carry the same meanings as those that come from more mature speakers. If you really want a straight answer, consider showing the two options to the toddler. But if you go that route, be prepared to hand over the cake.
For the first time, researchers have harnessed the body’s own chemistry to “grow” electrodes inside the tissues of living fish, blurring the boundary between biology and machines.
The technique uses the body’s sugars to turn an injected gel into a flexible electrode without damaging tissues, experiments show. Zebrafish with these electrodes grown in their brains, hearts and tail fins showed no signs of ill effects, and ones tested in leeches successfully stimulated a nerve, researchers report in the Feb. 24 Science. Someday, these electrodes could be useful for applications ranging from studying how biological systems work to improving human-machine interfaces. They also could be used in “bioelectronic medicine,” such as brain stimulation therapies for depression, Parkinson’s disease and other conditions (SN: 2/10/19).
Soft electronics aim to bridge the gap between soft, curvy biology and electronic hardware. But these electronics typically still must carry certain parts that can be prone to cracks and other issues, and inserting these devices inevitably causes damage to tissues.
“All the devices we have made, even though we have made them flexible, to make them more soft, when we introduce them, there will still be a scar. It’s like sticking a knife into the organ,” says Magnus Berggren, a materials scientist at Linköping University in Sweden. That scarring and inflammation can degrade electrode performance over time.
Previous efforts to grow soft electronics inside tissues have drawbacks. One approach uses electrical or chemical signals to power the transformation from chemical soup to conducting electrodes, but these zaps also cause damage. A 2020 study got around this problem by genetically modifying cells in worms to produce an engineered enzyme that does the job, but the new method achieves its results without genetic alterations.
Berggren and colleagues’ electrodes instead exploit a natural energy source already present in the body: sugars. The gel cocktail contains molecules called oxidases that react with the sugars — glucose or lactate — to produce hydrogen peroxide. That then activates another ingredient in the cocktail, an enzyme called hydrogen peroxidase, which is the catalyst needed to transform the gel into a conducting electrode.
“The approach leverages elegant chemistry to overcome many of the technical challenges,” says biomedical engineer Christopher Bettinger of Carnegie Mellon University in Pittsburgh, who was not involved in the study.
To test the technique, the researchers injected the cocktail into the brains, hearts and tail fins of transparent zebrafish. The gel turns blue when it becomes conductive, giving a visual readout of its success. “The beautiful thing is you can see it: The zebrafishes’ tail changes color, and we know that blue indicates a conducting polymer,” says materials scientist Xenofon Strakosas, also of Linköping University. “The first time I saw it, I thought ‘Wow, it’s really working!’”
The fish appeared to suffer no ill effects, and the researchers saw no evidence of tissue damage. In partially dissected leeches, the team showed that delivering a current to a nerve via a soft electrode could induce muscle contractions. Ultimately, devices like this could be paired with various wireless technologies in development.
Long-term implant performance remains to be determined, however. “The demonstrations are impressive,” Bettinger says. “What remains to be seen is the stability of the electrode.” Over time, substances in the body could react with the electrode materials, degrading it or even producing toxic substances.
The team still needs to refine how precisely the electrodes can stimulate nerves, says chemical engineer Zhenan Bao of Stanford University, who was not involved in the work. She and colleagues developed the way to “grow” electrical components using genetic modifications. Ensuring stimulation is concentrated where it’s needed for a treatment, while preventing the leakage of current to unwanted regions will be important, she says.
In the new study, the relative abundance of different sugars in different tissues determines exactly where electrodes form. But in the future, a component of the main ingredient could be swapped out for elements that attach to specific bits of biology to make targeting much more precise, Berggren says. “We’re conducting experiments right now where we’re trying to bind these materials directly on individual cells.” Notes Strakosas: “There are some applications where precision is really important; that’s where we have to invest effort.”
The best shot we have at minimizing the future impacts of climate change is to limit global warming to 1.5 degrees Celsius. Since the Industrial Revolution began, humankind has already raised the average global temperature by about 1.1 degrees. If we continue to emit greenhouse gases at the current rate, the world will probably surpass the 1.5-degree threshold by the end of the decade.
That sobering fact makes clear that climate change isn’t just a problem to solve someday soon; it’s an emergency to respond to now. And yet, most people don’t act like we’re in the midst of the greatest crisis humans have ever faced — not politicians, not the media, not your neighbor, not myself, if I’m honest. That’s what I realized after finishing The Climate Book by Greta Thunberg.
The urgency to act now, to kick the addiction to fossil fuels, practically jumps off the page to punch you in the gut. So while not a pleasant read — it’s quite stressful — it’s a book I can’t recommend enough. The book’s aim is not to convince skeptics that climate change is real. We’re well past that. Instead, it’s a wake-up call for anyone concerned about the future.
A collection of bite-size essays, The Climate Book provides an encyclopedic overview of all aspects of the climate crisis, including the basic science, the history of denialism and inaction, and what to do next. Thunberg, who became the face of climate activism after starting the Fridays For Future protests as a teenager (SN: 12/16/19), assembles an all-star roster of experts to write the essays.
The first two sections of the book lay out how a small amount of warming can have major, far-reaching effects. For some readers, this will be familiar territory. But as each essay builds on the next, it becomes clear just how delicate Earth’s climate system is. What also becomes clear is the significance of 1.5 degrees (SN: 12/17/18). Beyond this point, scientists fear, various aspects of the natural world might reach tipping points that usher in irreversible changes, even if greenhouse gas emissions are later brought under control. Ice sheets could melt, raise sea levels and drown coastal areas. The Amazon rainforest could become a dry grassland.
The cumulative effect would be a complete transformation of the climate. Our health and the livelihood of other species and entire ecosystems would be in danger, the book shows. Not surprisingly, essay after essay ends with the same message: We must cut greenhouse gas emissions, now and quickly.
Repetition is found elsewhere in the book. Numerous essays offer overlapping scientific explanations, stats about emissions, historical notes and thoughts about the future. Rather than being tedious, the repetition reinforces the message that we know what the climate change threat is, we know how to tackle it and we’ve known for a long time. Thunberg’s anger and frustration over the decades of inaction, false starts and broken pledges are palpable in her own essays that run throughout the book. The world has known about human-caused climate change for decades, yet about half of all human-related carbon dioxide emissions ever released have occurred since 1990. That’s the year the Intergovernmental Panel on Climate Change released its first report and just two years before world leaders met in Rio de Janeiro in 1992 to sign the first international treaty to curb emissions (SN: 6/23/90).
Perversely, the people who will bear the brunt of the extreme storms, heat waves, rising seas and other impacts of climate change are those who are least culpable. The richest 10 percent of the world’s population accounts for half of all carbon dioxide emissions while the top 1 percent emits more than twice as much as the bottom half. But because of a lack of resources, poorer populations are the least equipped to deal with the fallout. “Humankind has not created this crisis,” Thunberg writes, “it was created by those in power.”
That injustice must be confronted and accounted for as the world addresses climate change, perhaps even through reparations, Olúfẹ́mi O. Táíwò, a philosopher at Georgetown University, argues in one essay.
So what is the path forward? Thunberg and many of her coauthors are generally skeptical that new tech alone will be our savior. Carbon capture and storage, or CCS, for example, has been heralded as one way to curb emissions. But less than a third of the roughly 150 planned CCS projects that were supposed to be operational by 2020 are up and running.
Progress has been impeded by expenses and technology fails, science writer Ketan Joshi explains. An alternative might be “rewilding,” restoring damaged mangrove forests, seagrass meadows and other ecosystems that naturally suck CO2 out of the air (SN: 9/14/22), suggest environmental activists George Monbiot and Rebecca Wrigley.
Fixing the climate problem will not only require transforming our energy and transportation systems, which often get the most attention, but also our economies (endless growth is not sustainable), political systems and connection to nature and with each other, the book’s authors argue.
The last fifth of the book lays out how we could meet this daunting challenge. What’s needed is a critical mass of individuals who are willing to make lifestyle changes and be heard. This could trigger a social movement strong enough to force politicians to listen and create systemic and structural change. In other words, it’s time to start acting like we’re in a crisis. Thunberg doesn’t end the book by offering hope. Instead, she argues we each have to make our own hope.
“To me, hope is not something that is given to you, it is something you have to earn, to create,” she writes. “It cannot be gained passively, through standing by and waiting for someone else to do something. Hope is taking action.”
Modern birds evolved from dinosaurs, but it’s not clear how well birds’ ancient dino ancestors could fly (SN: 10/28/16). Now, a look at the fossilized feet of one nonavian dinosaur suggests that it may have hunted on the wing, like some hawks today.
The crow-sized Microraptor had toe pads very similar to those of modern raptors that can hunt in the air, researchers report December 20 in Nature Communications. That means the feathered, four-winged dinosaur probably used its feet to catch flying prey too, paleobiologist Michael Pittman of the Chinese University of Hong Kong and colleagues say (SN: 7/16/20). Other researchers caution that toe pads alone aren’t enough to declare Microraptor an aerial hunter. But if the claim holds up, such a hunting style would reinforce a debated hypothesis that powered flight evolved multiple times among dinosaurs, a feat once attributed solely to birds.
Toe pads are bundles of scale-covered flesh on the undersides of dinosaur feet, similar to “toe beans” on dogs and cats. Because the pads are points where the living animal interacted with surfaces, toe pads give paleontologists a “sense of where the rubber meets the road,” says Alexander Dececchi, a paleontologist at Mount Marty University in Yankton, S.D., who was not involved in the new study.
These contact points can paint a clearer picture of an animal’s behavior by providing “details that the skeleton itself wouldn’t show,” says Thomas Holtz Jr., a dinosaur paleobiologist at the University of Maryland in College Park, who was also not involved in the study.
To investigate dinosaur toe pads, Pittman and colleagues turned to the Shandong Tianyu Museum of Nature in Linyi, China. It “has arguably the largest collection of feathered dinosaurs in the world, and, importantly, they haven’t been prepared extensively,” Pittman says. Many of these dinosaur skeletons are still surrounded by rock, which is where soft tissues can be preserved. Such a specimen “gives us the best chance of finding this wonderful soft tissue information,” he says. Using special lasers that cause the otherwise nearly invisible soft tissue in the fossils to fluoresce, the team found 12 specimens with exceptionally well-preserved toe pads among the thousands examined (SN: 3/20/17).
The team compared the fossil toe pads with those of 36 types of modern birds, whose toe pads vary with their lifestyle. Predatory birds, for example, have protruding toe pads with spiky scales for grasping prey, while ground birds that spend their time walking and running have flatter toe pads. The analysis showed that Microraptor’s toe pads and other aspects of the feet, like the shape of the toe joints and claws, are most like those of modern hawks. That similarity suggests that the dinosaur could hunt prey midair and on the ground like hawks do, the team says.
Other dinosaurs, like the feathered Anchiornis, had flatter toe pads and straighter claws, suggesting a terrestrial lifestyle. That’s in line with ideas about this dinosaur being a poor flier, Pittman says. The idea that Microraptor hunted like a hawk is consistent with other fossil evidence. One Microraptor fossil has been found with a bird in its stomach, and Microraptor‘s skeletal and soft tissue anatomy suggest some powered flight capability.
There’s still more work to do to figure out how well the dinosaur may have flown. “Microraptor is not a bird, but a close relative. Just because it has feet like a predatory bird doesn’t necessarily mean it must be catching prey in the exact same way,” Pittman says. But Microraptor’s hawklike lifestyle “is a strong possibility,” he adds. Flight could have been useful to Microraptor when hunting, even if it couldn’t stack up to today’s fliers. Dececchi speculates that Microraptor’s anatomy probably prevented it from outflying birds, but may have helped it surprise otherwise out-of-reach prey, including flying and gliding animals.
“You only have to be fast or aerobatic enough to catch other things in your environment,” Holtz says. “So, it’s not improbable that [Microraptor was] catching things in the air on occasion.”
Other paleontologists are more skeptical that Microraptor hunted on the wing. “It would be a bit of a stretch to me to suggest that Microraptor was pursuing prey in an aerial context,” says Albert Chen, a paleobiologist at the University of Cambridge. The new findings inform only “what the foot was used for.”
Alternative hypotheses, such as a completely or partially terrestrial hunting style, could fit the data too, Holtz says, but the “feet are definitely playing a major role in their prey capture,” whether on the ground or in the air.
For now, the picture of Microraptor’s ecology remains fuzzy, but as lasers continue to increase the picture’s resolution, our understanding of dinosaur flight may reach new heights.
The sperm whale is an endangered species. A major reason is that the whale oil is heat-resistant and chemically and physically stable. This makes it useful for lubricating delicate machinery. The only substitute is expensive carnauba wax from the leaves of palm trees that grow only in Brazil … [but] wax from the seeds of the jojoba, an evergreen desert shrub, is nearly as good.
Update After sperm whale oil was banned in the early 1970s, the United States sought to replenish its reserves with eco-friendly oil from jojoba seeds (SN: 5/17/75, p. 335). Jojoba oil’s chemical structure is nearly identical to that of sperm whale oil, and the shrub is native to some North American desert ecosystems, making the plant an appealing replacement. Today, jojoba shrubs are cultivated around the world on almost every continent. Jojoba oil is used in hundreds of products, including cosmetics, pharmaceuticals, adhesives and lubricants. Meanwhile, sperm whale populations have started to recover under international anti-whaling agreements (SN: 2/27/21, p. 4).
Some thumbnail-sized, brown male spiders in Georgia could be miffed if they paid the least attention to humans and our news obsessions.
Recent stories have made much of “giant” jorō spiders invading North America from eastern Asia, some large enough to span your palm. Lemon yellow bands cross their backs. Bright red bits can add drama, and a softer cheesecake yellow highlights the many joints on long black legs.
The showy giants, however, are just the females of Trichonephila clavata. Males hardly get mentioned except for what they’re not: colorful or big. A he-spider hulk at 8 millimeters barely reaches half the length of small females. Even the species nickname ignores the guys. The word jorō, borrowed from Japanese, translates to such unmasculine terms as “courtesan,” “lady-in-waiting” and even “entangling or binding bride.” Mismatched sexes are nothing new for spiders. The group shows the most extreme size differences between the sexes known among land animals, says evolutionary biologist Matjaž Kuntner of the Evolutionary Zoology Lab in Ljubljana, Slovenia. The most dramatic case Kuntner has heard of comes from Arachnura logio scorpion spiders in East Asia, with females 14.8 times the size of the males.
With such extreme size differences, mating conflicts in animals can get violent: females cannibalizing males and so on (SN: 11/13/99). As far as Kuntner knows, however, jorō spiders don’t engage in these “sexually conflicted” extremes. Males being merely half size or thereabouts might explain the relatively peaceful encounters.
When it comes to humans, these spiders don’t bother anybody who doesn’t bother them. But what a spectacle they make. “I’ve got dozens and dozens in my yard,” says ecologist Andy Davis at the University of Georgia in Athens. “One big web can be 3 or 4 feet in diameter.” Jorō spiders have lived in northeastern Georgia since at least 2014. These new neighbors inspired Davis and undergraduate Benjamin Frick to see if the newcomers withstand chills better than an earlier invader, Trichonephila clavipes, their more tropical relative also known as the golden silk orb-weaver. (The jorō also can spin yellow-tinged silk.) The earlier arrival’s flashy females and drab males haven’t left the comfy Southeast they invaded at least 160 years ago.
Figuring out the jorō’s hardiness involves taking the spider’s pulse. But how do you do that with an arthropod with a hard exoskeleton? A spider’s heart isn’t a mammallike lump circulating blood through a closed system. The jorō sluices its bloodlike fluid through a long tube open at both ends. “Think of a garden hose,” says Davis. He has measured heart rates of monarch caterpillars, and he found a spot on a spider’s back where a keen-eyed observer can count throbs.
Female jorō spiders packed in ice to simulate chill stress kept their heart rates some 77 percent higher than the stay-put T. clavipes, tests showed. Checking jorō oxygen use showed females have about twice the metabolic rate. And about two minutes of freezing temperatures showed better female survival (74 percent versus 50 percent). Lab tests used only the conveniently big jorō females, though male ability to function in random cold snaps could matter too.
Plus jorō sightings in the Southeast so far suggest the newer arrival needs less time than its relative to make the next generation, an advantage for farther to the north. The adults don’t need to survive deep winter in any case. Mom and dad die off, in November in Georgia, and leave their hundreds of eggs packed in silk to weather the cold and storms.
Reports on the citizen-observer iNaturalist site suggest that in Georgia, jorō spiders already cover some 40,000 square kilometers, Davis and Frick report February 17 in Physiological Entomology. Sightings now stretch into Tennessee and the Carolinas. But how far the big moms and tiny dads will go and when, we’ll just have to wait and see.
