The Biological Rulebook Was Just Rewritten—by Ants

Welcome back to the Abstract! Here are the studies this week that transgressed the rules, explored extraterrestrial vistas, and went with the flow.

First, ants are doing really strange things again. I don’t even want to spoil it—you’ll just have to read on! Then, plan your trip to the latest hot exoplanet destination (literally, in the case of the lava planets), and check out Saturn’s new bling on the way. Lastly, all aboard on a trip to the riverboats of the past.

Same mama, different species

Y. Juvé, C. Lutrat, A. Ha, et al. “One mother for two species via obligate cross-species cloning in ants.” Nature.

Scientists have discovered a gnarly reproductive strategy that is unlike anything ever documented in nature: Ant queens that produce offspring from two entirely different species by cloning the “alien genome” of males from another lineage. This unique behavior has been  dubbed “xenoparity,” according to a new study.

Researchers were first tipped off to this bizarre adaptation after they kept finding builder harvester ants (Messor structor) in the colonies of Iberian harvester ants (Messor ibericus). Field and laboratory observations revealed that, in addition to mating with males of their own species, M. ibericus queens mate with M structor. The queens store and clone this sperm to produce hybrids with M. structor genomes and M. ibericus mitochondria. Even though these two ant species diverged five million years ago and don’t share the exact same range, the queens rely on M. structor males exclusively for its worker caste, suggesting a “domestication-like process,” the study reports.

“Living organisms are assumed to produce same-species offspring,” said researchers co-led by Y. Juvé, C. Lutrat, and A. Ha of the University of Montpellier. “Here, we report that this rule has been transgressed by Messor ibericus ants, with females producing individuals from two different species.”

“M. ibericus queens strictly depend on males of M. structor, which is a well-differentiated, non-sister species,” the team added. “To our knowledge, females needing to clone members of another species have not previously been observed.”

Iberian harvester queens only produce females when they mate within their own species, which may have prompted this cross-species adaptation. By producing cloned M. structor males, the queens ensure the continuation of a worker caste as well as a supply of male mates for later generations of queens. 

“At the intraspecific level, several cases of ants cloning males from their own species’ sperm have been observed,” the researchers noted. “Here, our results imply that this phenomenon has crossed species barriers.”

“Taken together, these results further support the idea that clonal males should be characterized as a domesticated lineage of M. structor,” they continued. “Although matching all criteria of domestication, the relationship we describe is both more intimate and integrated than the most remarkable examples known so far.”

What’s next, dogs giving birth to whales? Probably not, but still, these transgressive queens have rewritten the reproductive rulebook in a truly astonishing way.

In other news…  

Vacationing really far abroad 

Dovey, Ceridwen. Imagining exoplanets as destinations: a case study of artist-scientist collaborations on NASA's iconic Exoplanet Travel Bureau posters. Journal of Science Communication.

In 2015, NASA released a bunch of splashy retro posters that imagined exoplanets as travel destinations, as part of a collaborative project between scientists and artists. A new study dissects the huge success of that campaign, which engaged the public in the burgeoning field of exoplanet research and helped scientists visualize their distant observational targets.

Exoplanet posters. Image: NASA

The Exoplanet Travel Bureau posters “were not images designed to be understood by the public as objectively ‘real’ or ‘scientific’, yet they were still scientifically informed,” said author Ceridwen Dovey of Macquarie University. “As tourism posters proposing travel to extremely distant exoplanets, they were not pretending to be direct images of astronomical objects, yet they were also not pure speculation or fantasy. They sat very comfortably—and alluringly—somewhere in between.”

There’s always a fine line to tread when depicting alien exoplanets, given how little we know about what it is really like on these distant worlds. But since interstellar travel does not seem to be coming anytime soon, the NASA posters served as a powerful imaginative stopgap for thinking about these new worlds—even if their amenities remain unknown. 

Saturn has ‘strange dark arms’ and beads to match its rings

Stallard, Tom S. et al. “JWST/NIRSpec Detection of Complex Structures in Saturn's Sub-Auroral Ionosphere and Stratosphere.” Geophysical Research Letters.

The James Webb Space Telescope is most famous for peering farther back in space and time than ever before, revealing amazing insights about the early universe. But JWST is also shedding light on planets right in our own backyard, as evidenced by a new study about “dark beads” and “strange dark arms” that showed up in its observations of Saturn. 

These features arise from Saturn's stratosphere and ionosphere, which were captured in "unprecedented detail” by JWST’s near-infrared instruments. The “arms” are methane-gas  structures that extend down from the poles toward the equator while the beads emerge “in a variety of sizes and shapes” on one side of the ionosphere.

“This stratospheric structure is again unlike anything previously observed at other planets,” said researchers led by Tom Stallard of Northumbria University. “While we do not understand how or why these dark arms are generated, it is perhaps noteworthy that they occur in a region where the underlying atmosphere is also disturbed, suggesting this stratospheric layer might be influenced from below.”

Given its famous rings and now its beads, my prediction is that they will discover a bedazzled bangle on Saturn next.

Up history’s creek without a paddle

Filet, Clara et al. “As the water flows: A method for assessing river navigability in the past.” Journal of Archaeological Science.

Rivers are often employed as metaphors for the passage of time into the future, but a new study is paddling upstream into the past. The goal was to reconstruct the navigability of rivers in ancient times, which is important information for understanding past trade networks, migrations, and social connections. However, it is difficult to pinpoint how ancient peoples traversed these waterways using only archeological sites and historical documents.

“The very notion of a navigable river seems problematic, as the possibilities for navigation on a river are highly dependent on the section considered, the type of boat, the climate and seasonal cycles,” said researchers led by Clara Filet of the Bordeaux Montaigne University. 

To address this gap, the researchers developed an algorithm that searched for flat and calm stretches of a river, called “plain sections.” They tested out their approach on dozens of rivers used by cultures in ancient Gaul and Roman and concluded that it “provides a good approximation of navigable sections.” 

“Applying this method offers a new perspective on navigable areas in the Roman world, providing a reasonable first guess that could guide future empirical research into the navigability of ancient rivers,” the team concluded.

Thanks for reading! See you next week.