Ground beetle genitals have the genetic ability to get strange. They don’t

A new peek at the genetics of beetle genitals reveals the underpinnings of a battle of the sexes.

When mating, males of Japan’s flightless Carabus beetles insert a chitin-covered appendage that, once inside a female, pops out a plump sperm-delivery tube as well as a side projection called a copulatory piece. That piece doesn’t deliver any sperm, but steadies the alignment by fitting just so into a special pocket inside the female reproductive tract.

Researchers in Japan have now identified several regions of DNA that include genes controlling the length and width of the piece and pocket. Instead of being controlled mostly by the same genes, the beetles seem to have a fair amount of genetic freedom in changing one sex’s doodad dimensions without also resizing the other sex’s counterpart, evolutionary ecologist Teiji Sota of Kyoto University and colleagues say June 26 in Science Advances.
Within a given species of these beetles, males and females have evolved compatible sizes, but the capacity for mismatching shows up in hybrids. Out-of-sync sizes can cause ruptures, snap-offs and generally low numbers of offspring. This misfortune matters not just to a few unlucky beetles, but to the whole process of forming species, or speciation.

“I personally think that one of the greatest remaining mysteries in evolutionary biology is the role of genital evolution in speciation,” says Justa Heinen-Kay of the University of Minnesota in St. Paul. She was not part of the beetle work, but has studied fish genital evolution. Across the animal kingdom, shapes of genitals are among the most rapidly evolving traits, she points out. There are species that otherwise look almost exactly alike that specialists distinguish by differences in genitals.

One early idea linking genital shape with the formation of species proposed that developing a unique his-and-hers fit worked as a lock and key that separated members of one species from another. One of Sota’s early papers, in 1998, proposed that the genital quirks of the ground beetles worked as just this kind of separator of species.
The lock-and-key concept sounded great, says Brian Langerhans of North Carolina State University in Raleigh. But disputes over evidence of the process led “to many believing it played little role in reality.” Recently though, he says, the idea is rousing interest again.

Sota has started exploring the genetics governing size in the ground beetles’ proposed locks and keys. Earlier research had suggested a battle of the sexes over genital size. Longer could be better for a male, as it may help outcompete a less-endowed guy in the struggle to fertilize a female’s egg. Yet longer male parts can damage females, unless a female’s parts lengthen, too. Biologists have proposed that certain traits, for instance the sizes of his and her organs, stay in sync in a species because the same genes influence both the male and female form. Appealing as that idea might sound, in this case, the beetle researchers are now arguing against it.

The evidence comes from analyzing the odd genital forms in hybrids of two beetle species that manage to mate. The patterns of variety in the offsprings’ genital width and length suggest that genes for female pocket width are not tied to male piece width, and are only loosely related to male length. The females thus have some freedom genetically to vary on their own. What’s keeping male and female parts in sync for the beetles, Sota suggests, is not shared genes but shared consequences. Parents with the wrong-sized genitals just don’t have a lot of offspring.

Many fictional moon voyages preceded the Apollo landing

From the beginning, the moon has been humankind’s perpetual nighttime companion.

Accompanied by innumerable points of light, the moon’s luminous disk hovered overhead like a dim substitute for the sun, just with a shape not so constant. Rather the moon waxed and waned, diminishing to a barely discernible sliver before disappearing and then gradually restoring itself to fullness.

It was obviously far away, yet sometimes — especially when on the horizon — seemed so near. Its size, its phases, its peculiar blemishes resembling a face, made the moon an enduring mystery for all ancient civilizations.

In virtually every culture throughout history, the moon acquired an elaborate mythology. For the Greeks the moon was the goddess Selene (or Artemis, or Phoebe); for the Romans, Luna or Diana; for the Chinese, Chang’e. For some other cultures — the Inuit peoples of the Arctic, for instance — the moon was a male deity.
As astronomical objects go, the sun could certainly claim a more prominent impact on human affairs — illuminating darkness, providing warmth, nourishing the growth of vegetation essential to sustaining life. But the sun did its job out in the open, in (obviously) the light of day. The moon was more mysterious. Primitive skywatchers speculated about the source of its light, what it was made of and whether it was inhabited. It inspired wonder, and curiosity, and therefore played no small part in inspiring the origin of science itself.

As the story commonly goes, early Greek philosophers gave birth to science by seeking rational, logical explanations for natural phenomena in preference to mythological explanations — replacing mythos with logos. But as the historian Liba Taub has pointed out, Greek philosophy did not really dispose of mythos, but rather merged it with logos — or if not a merger, at least a juxtaposition. Mythos and logos could both in some context merely mean “story.” And so for the Greeks, mythos was not always opposed to logos, Taub wrote in her book Aetna and the Moon; “they were recognized forms of discourse that could, on occasion, both be invoked, and each could lay claim to the truth.” Philosophers such as Parmenides, Empedocles and Plato used mythlike narrative to convey essentially scientific ideas.

In no case was the mythos-logos juxtaposition more clearly in force than with the moon. In the first century, the Greek-Roman writer Plutarch’s On the Face which Appears on the Orb of the Moon explored via dialog Greek scientific opinions about the moon: the nature of eclipses, whether the moon shone on its own or reflected light from the sun, whether the moon was made of earthlike matter or celestial crystal. But the speakers in Plutarch’s dialog did not restrict themselves to scientific matters, also discussing the belief that the moon served as a receptacle for souls leaving earthly bodies upon death.

In Plutarch’s discussion, “science and myth are in dialogue,” Taub wrote. “Scientific enquiry and mythological explanation are not set up as rivals; rather, they are presented as two complementary aspects of a full consideration of nature.”

Even after the ascendancy of modern science, the moon retained its cultural and mythological presence, in literature and poetry, song and film. Full moons cause madness, or crime, or turn people into werewolves. Entertainers sing of dancing in the moonlight, a bad moon on the rise or being followed by a moonshadow. Frank Sinatra crooned “Fly Me to the Moon.” Cher was Moonstruck, and Jimmy Stewart declared his love for Donna Reed by offering to lasso the moon and bring it down to Earth. Humans have always been lunatics about the moon.

No wonder people have long imagined going there.

Among the earliest dreamers of a lunar voyage was Lucian of Samosata, a Syrian satirist born about A.D. 120. His Vera Historia (A True Story, “true” being the satirical part) recounts an ocean voyage gone wrong when a waterspout lifted Lucian’s boat into the sky, landing it (after seven days of flight) on the moon. Lucian and his companions found the moon full of various weird, huge forms of life, kind of like what you’d expect to find in the Forbidden Forest outside Hogwarts (a flea the size of a dozen elephants, for example).
By some accounts, Lucian’s “true” story was the first true work of science fiction. But some sci-fi authorities reserve that honor for the prominent astronomer Johannes Kepler, whose Somnium (The Dream) was published in 1634, four years after Kepler’s death. Kepler did not imagine flying to the moon himself, but wrote of a dream in which a demon described the moon’s inhabitants to an Icelandic boy and his mother, a witch (not associated with Hogwarts).

After Kepler’s Somnium, moon voyages became a popular fascination with various writers, Cyrano de Bergerac and Daniel Defoe among them. In 1638, for instance, English historian and author Francis Godwin published a short novel called The Man in the Moone, telling of the adventures of a Spaniard named Domingo Gonsales. Gonsales managed to train a group of migratory swans to wear harnesses and fly him around in an “engine” he had devised. But unknown to Gonsales, the swans’ migration took them regularly to the moon. He described a 12-day journey watching the Earth recede from view as the swans delivered him to the lunar surface. There he encountered a utopian lunar society, with inhabitants extraordinarily tall, and with no illness, crime or need for any lawyers.

Around the same time another Englishman, the philosopher and clergyman John Wilkins, composed

A Discourse Concerning a New World and Another Planet, a fully scientific discussion of the moon and the possibility of voyaging there. Wilkins analyzed all the scientific questions about the moon and the possibility of its habitation, and seriously considered the prospect of visiting it. “Tis possible for some of our posterity, to find out a conveyance to this other world,” he wrote.

Wilkins argued that the air between Earth and moon might not be so cold and thin as some had supposed, and that future technology might permit humans to attain a height above the reach of Earth’s gravity. (Lack of gravity offered the additional advantage of requiring no expenditure of energy and hence no need for food during the journey.)

Possibly, Wilkins speculated, a human might achieve flight by attaching wings, or perhaps by riding on the back of a large bird. If neither of those two plans turned out to be feasible, Wilkins offered a third: “I do seriously, and upon good grounds, affirm it possible to make a flying chariot, in which a man may sit, and give such a motion unto it, as shall convey him through the air.” And Wilkins foresaw fame and fortune for such a chariot’s inventor: “The perfecting of such an invention, would be of such excellent use, that it were enough, not only to make a man famous, but the age also wherein he lives. For besides the strange discoveries that it might occasion in this other world, it would be also of inconceivable advantage for travelling, above any other conveyance that is now in use.”

For both Godwin and Wilkins, flying to the moon seemed feasible, as in those days nobody knew that the vacuum of space separated the top of the Earth’s atmosphere from the lunar surface. Only later in the 17th century, when experiments established the reality of a vacuum, and Isaac Newton’s laws specified the mechanical and gravitational impediments, did the dreams of moon visitation seem most likely unattainable.

But dreamers still dreamed. In 1827, one Joseph Atterley (pseudonym for George Tucker, a University of Virginia professor who had once been a U.S. congressman) wrote A Voyage to the Moon. Atterley traveled in a copper vessel powered by “lunarium,” an antigravitational metal (repelled by the Earth, but attracted to the moon) discovered in Burma. Later in the 19th century Jules Verne wrote the more famous From the Earth to the Moon, in which propulsion for the space capsule was provided by a powerful cannon.

All the while that the moon mesmerized songwriters and novelists, it provided similar inspiration for science. Lunar cycles and their importance for creating an accurate calendar were major aspects of ancient and medieval science, as was the moon’s role in eclipses, a foundational element in the development of astronomy. Isaac Newton, of course, made science truly modern following his realization that the moon was just like a falling apple, guided by gravity (only in the moon’s case, falling around the Earth instead of into it). And while showing how difficult it might be to overcome the Earth’s gravity and fly to the moon, Newton’s physics at the same time specified exactly the mechanical requirements to do so. Rocket technology for meeting those requirements, developed in the 20th century, produced the multistage Saturn V that launched Apollo astronauts Neil Armstrong, Buzz Aldrin and Michael Collins on their way to the moon half a century ago.

Perhaps it was that success in achieving John F. Kennedy’s vision, of landing a man on the moon and returning him safely to Earth, that most dramatically demonstrated the merger of myth with logos, of lunar science with the moon’s cultural relevance. Armstrong’s first small step reminded all humankind of its essential unity as a single community in the cosmos — the moon serving as symbol for all that every member of the human race has in common. After July 20, 1969, it became truer than ever what Jules Verne wrote in the opening pages of From the Earth to the Moon, when Impey Barbicane proposed such a voyage to the members of his club: “There is no one among you, my brave colleagues, who has not seen the Moon, or, at least, heard speak of it.”

Boa suffocation is merely myth

Boa constrictors don’t so much suffocate prey as break their hearts. It turns out that the snakes kill like demon blood pressure cuffs, squeezing down circulation to its final stop. The notion that constrictors slay by preventing breathing turns out to be wrong.

The snakes don’t need limbs, or even venom, to bring down an animal of their own size. “Imagine you’re killing and swallowing a 150-pound animal in one meal — with no hands or legs!” animal ecologist Scott Boback tells his students at Dickinson College in Carlisle, Pa., to convey what extraordinary hunters snakes are. Speed matters with prey flailing claws, hooves or other weaponry the snake lacks. Embracing prey into heart failure is faster than suffocating it and appeared in different forms multiple times in snake history.
Ambushing birds, monkeys and a wide range of other animals from Mexico south to Argentina, the iconic Boa constrictor attacks in much the same way each time. The snake cinches a loop or two around the upper body of prey, pressing against its victim hard enough to starve organs of oxygenated blood.

“It’s not some unbelievable amount of pressure,” says Boback, whose arms get snaked now and then. “It stings a little — you can kind of feel the blood stop,” he says.
Within six seconds of looping around an anesthetized lab rat, a boa constrictor squeezes enough to halve blood pressure in a rear-leg artery. Blood that should surge through the artery lies dammed behind snake coils in the rat’s upper body. And back pressure keeps the rat heart from pumping out new blood. Circulation falters and fails. Boas release their grip after about six minutes on average, Boback and his colleagues report in the July 15 Journal of Experimental Biology.

Then the boa swallows the catch whole. A rat about a quarter of the snake’s weight disappears down the gullet in a couple of minutes. Moveable bones in the head help the snake make the gulp, as does a dimple of stretchy cartilage that lets the chin open wide. But what people most often tell Boback — that snake jaws must separate at the back — is just another serpentine myth.

Here’s why icicles made from pure water don’t form ripples

Icicles made from pure water give scientists brain freeze.

In nature, most icicles are made from water with a hint of salt. But lab-made icicles free from salt disobey a prominent theory of how icicles form, and it wasn’t clear why. Now, a study is helping to melt away the confusion.

Natural icicles tend to look like skinny cones with rippled surfaces — the result of a thin film of water that coats the ice, researchers think (SN: 11/24/13). As icicles grow, the film freezes. Any preexisting small bumps in the icicle get magnified into large ripples because the water layer is thinner above the bumps and can freeze more readily. But this theory fails to explain the salt-free variety, which have more irregular shapes reminiscent of drippy candles, says physicist Menno Demmenie of the University of Amsterdam.
So Demmenie and colleagues grew icicles in the lab, adding a blue dye that was visible only when the water was liquid. Salted icicles not only had ripples, but they also were covered in a thin, blue film. Icicles made from pure water had no such film. Only small droplets of blue appeared on those icicles, the team reports in the February Physical Review Applied.

In icicles with salt, the temperature at which the water on the surface freezes is lowered, allowing a liquid layer to coat the entire icicle. Without the salt, icicles must build up drop by drop.

Scientists have found the first known microbes that can eat only viruses

Tiny, pond-dwelling Halteria ciliates are virovores, able to survive on a virus-only diet, researchers report December 27 in Proceedings of the National Academy of Sciences. The single-celled creatures are the first known to thrive when viruses alone are on the menu.

Scientists already knew that some microscopic organisms snack on aquatic viruses such as chloroviruses, which infect and kill algae. But it was unclear whether viruses alone could provide enough nutrients for an organism to grow and reproduce, says ecologist John DeLong of the University of Nebraska–Lincoln.
In laboratory experiments, Halteria that were living in water droplets and given only chloroviruses for sustenance reproduced, DeLong and colleagues found. As the number of viruses in the water dwindled, Halteria numbers went up. Ciliates without access to viral morsels, or any other food, didn’t multiply. But Paramecium, a larger microbe, didn’t thrive on a virus-only diet, hinting that viruses can’t satisfy the nutritional requirements for all ciliates to grow.

Viruses could be a good source of phosphorus, which is essential for making copies of genetic material, DeLong says. But it probably takes a lot of viruses to account for a full meal.

In the lab, each Halteria microbe ate about 10,000 to 1 million viruses daily, the team estimates. Halteria in small ponds with abundant viral snacks might chow down on about a quadrillion viruses per day.

These feasts could shunt previously unrecognized energy into the food web, and add a new layer to the way viruses move carbon through an ecosystem — if it happens in the wild, DeLong says (SN: 6/9/16). His team plans to start finding out once ponds in Nebraska thaw.

Readers discuss jazz music, the next generation of astronauts and more

In full swing
The swaying feeling in jazz music that compels feet to tap may arise from near-imperceptible delays in musicians’ timing, Nikk Ogasa reported in “Jazz gets its swing from small, subtle delays” (SN: 11/19/22, p. 5).

Reader Oda Lisa, a self-described intermediate saxophonist, has noticed these subtle delays while playing.“I recorded my ‘jazzy’ version of a beloved Christmas carol, which I sent to a friend of mine,” Lisa wrote. “She praised my effort overall, but she suggested that I get a metronome because the timing wasn’t consistent. My response was that I’m a slave to the rhythm that I hear in my head. I think now I know why.”
On the same page
Murky definitions and measurements impede social science research, Sujata Gupta reported in “Fuzzy definitions mar social science” (SN: 11/19/22, p. 10).

Reader Linda Ferrazzara found the story thought-provoking. “If there’s no consensus on the terms people use … then there can be no productive discussion or conversation. People end up talking and working at cross-purposes with no mutual understanding or progress,” Ferrazzara wrote.

Fly me to the moon
Space agencies are preparing to send the next generation of astronauts to the moon and beyond. Those crews will be more diverse in background and expertise than the crews of the Apollo missions, Lisa Grossman reported in “Who gets to go to space?” (SN: 12/3/22, p. 20).

“It is great to see a broader recognition of the work being done to make spaceflight open to more people,” reader John Allen wrote. “Future space travel will and must accommodate a population that represents humanity. It won’t be easy, but it will be done.”

The story also reminded Allen of the Gallaudet Eleven, a group of deaf adults who participated in research done by NASA and the U.S. Navy in the 1950s and ’60s. Experiments tested how the volunteers responded (or didn’t) to a range of scenarios that would typically induce motion sickness, such as a ferry ride on choppy seas. Studying how the body’s sensory systems work without the usual gravitational cues from the inner ear allowed scientists to better understand motion sickness and the human body’s adaptation to spaceflight.

Sweet dreams are made of this
A memory-enhancing method that uses sound cues may boost an established treatment for debilitating nightmares, Jackie Rocheleau reported in “L­earning trick puts nightmares to bed” (SN: 12/3/22, p. 11).

Reader Helen Leaver shared her trick to a good night’s sleep: “I learned that I was having strong unpleasant adventures while sleeping, and I would awaken hot and sweaty. By eliminating the amount of heat from bedding and an electrically heated mattress pad, I now sleep well without those nightmares.”
Pest perspectives
In “Why do we hate pests?” (SN: 12/3/22, p. 26), Deborah Balthazar interviewed former Science News Explores staff writer Bethany Brookshire about her new book, Pests. The book argues that humans — influenced by culture, class, colonization and much more — create animal villains.

The article prompted reader Doug Clapp to reflect on what he considers pests or weeds. “A weed is a plant in the wrong place, and a pest is an animal in the wrong place,” Clapp wrote. But what’s considered “wrong” depends on the humans who have power over the place, he noted. “Grass in a lawn can be a fine thing. Grass in a garden choking the vegetables I’m trying to grow becomes a weed. Mice in the wild don’t bother me. Field mice migrating into my house when the weather cools become a pest, especially when they eat into my food and leave feces behind,” Clapp wrote.

The article encouraged Clapp to look at pests through a societal lens: “I had never thought of pests in terms of high-class or low-class. Likewise, the residual implications of [colonization]. Thanks for provoking me to consider some of these issues in a broader context.”

Mysterious marks on Ice Age cave art may have been a form of record keeping

As far back as roughly 25,000 years ago, Ice Age hunter-gatherers may have jotted down markings to communicate information about the behavior of their prey, a new study finds.

These markings include dots, lines and the symbol “Y,” and often accompany images of animals. Over the last 150 years, the mysterious depictions, some dating back nearly 40,000 years, have been found in hundreds of caves across Europe.

Some archaeologists have speculated that the markings might relate to keeping track of time, but the specific purpose has remained elusive (SN: 7/9/19). Now, a statistical analysis, published January 5 in Cambridge Archeological Journal, presents evidence that past people may have been recording the mating and birthing schedule of local fauna.
By comparing the marks to the animals’ life cycles, researchers showed that the number of dots or lines in a given image strongly correlates to the month of mating across all the analyzed examples, which included aurochs (an extinct species of wild cattle), bison, horses, mammoth and fish. What’s more, the position of the symbol “Y” in a sequence was predictive of birth month, suggesting that “Y” signifies “to give birth.”

The finding is one of the earliest records of a coherent notational system, the researchers say. It indicates that people at the time were able to interpret the meaning of an item’s position in a sequence and plan ahead for the distant future using a calendar of sorts — reinforcing the suggestion that they were capable of complex cognition.
“This is a really big deal cognitively,” says Ben Bacon, an independent researcher based in London. “We’re dealing with a system that has intense organization, intense logic to it.”

A furniture conservator by day, Bacon spent years poring through scientific articles to compile over 800 instances of these cave markings. From his research and reading the literature, he reasoned that the dots corresponded to the 13 lunar cycles in a year. But he thought that the hunter-gatherers would’ve been more concerned with seasonal changes than the moon.

In the new paper, he and colleagues argue that rather than pinning a calendar to astronomical events like the equinox, the hunter-gatherers started their calendar year with the snowmelt in the spring. Not only would the snowmelt be a clear point of origin, but the meteorological calendar would also account for differences in timing across locations.
For example, though snowmelt would start on different dates in different latitudes, bison would always mate approximately four lunar cycles — or months — after that region’s snowmelt, as indicated by four dots or lines.

“This is why it’s such a clever system, because it’s based on the universal,” Bacon says. “Which means if you migrate from the Pyrenees to Belgium, you can just use the same calendar.”

He needed data to prove his idea. After compiling the markings, he worked with academic researchers to identify the timing of migration, mating and birth for common Ice Age animals targeted by hunter-gatherers by using archaeological data or comparing with similar modern animals. Next, the researchers determined if the marks aligned significantly with important life events based on this calendar. When the team ran the statistical analysis, the results strongly supported Bacon’s theory.

When explaining the markings, “we’ve argued for notational systems before, but it’s always been fairly speculative as to what the people were counting and why they were counting,” says Brian Hayden, an archaeologist at Simon Fraser University in Burnaby, British Columbia, who peer-reviewed the paper. “This adds a lot more depth and specificity to why people were keeping calendars and how they were using them.”

Linguistic experts argue that, given the lack of conventional syntax and grammar, the marks wouldn’t be considered writing. But that doesn’t make the finding inherently less exciting, says paleoanthropologist Genevieve von Petzinger of the Polytechnic Institute of Tomar in Portugal, who wasn’t involved in the study. Writing systems are often mistakenly considered a pinnacle of achievement, when in fact writing would be developed only in cultural contexts where it’s useful, she says. Instead, it’s significant that the marks provide a way to keep records outside of the mind.

“In a way, that was the huge cognitive leap,” she says. “Suddenly, we have the ability to preserve [information] beyond the moment. We have the ability to transmit it across space and time. Everything starts to change.”

The debate over these marks’ meanings continues. Archaeologist April Nowell doesn’t buy many of the team’s assumptions. “It boggles my mind why one would need a calendar … to predict that animals were going to have offspring in the spring,” says Nowell, of the University of Victoria in British Columbia. “The amount of information that this calendar is providing, if it really is a calendar, is quite minimal.”

Hayden adds that, while the basic pattern would still hold, some of the cave marks had “wiggle room for interpretation.” The next step, he says, will be to review and verify the interpretations of the marks.