Dawn’s mission was extended several times, outperforming scientists’ expectations in its exploration of two planet-like bodies, Ceres and Vesta, that make up 45 percent of the mass of the main asteroid belt. Now the spacecraft is about to run out of a key fuel, hydrazine. When that happens, most likely between mid-September and mid-October, Dawn will lose its ability to communicate with Earth. It will remain in a silent orbit around Ceres for decades.

“Although it will be sad to see Dawn’s departure from our mission family, we are intensely proud of its many accomplishments,” said Lori Glaze, acting director of the Planetary Science Division at NASA Headquarters in Washington. “Not only did this spacecraft unlock scientific secrets at these two small but significant worlds, it was also the first spacecraft to visit and orbit bodies at two extraterrestrial destinations during its mission. Dawn’s science and engineering achievements will echo throughout history.”

When Dawn launched from Cape Canaveral Air Force Station in Florida in September 2007, strapped on a Delta II-Heavy rocket, scientists and engineers had an idea of what Ceres and Vesta looked like. Thanks to ground- and space-based telescopes, including NASA’s Hubble Space Telescope, the bodies in the asteroid belt between Mars and Jupiter were visible — but even the best pictures were fuzzy.

From 2011 to 2012, Dawn swept over Vesta, capturing images that exceeded everyone’s imaginings — craters, canyons and even mountains. Then on Ceres in 2015, Dawn showed us a cryovolcano and mysterious bright spots, which scientists later found might be salt deposits produced by the exposure of briny liquid from Ceres’ interior. Through Dawn’s eyes, these bright spots were especially stunning, glowing like diamonds scattered across the dwarf planet’s surface.

“Dawn’s legacy is that it explored two of the last uncharted worlds in the inner Solar System,” said Marc Rayman of NASA’s Jet Propulsion Laboratory in Pasadena California, who serves as Dawn’s mission director and chief engineer. “Dawn has shown us alien worlds that for two centuries were just pinpoints of light amidst the stars. And it has produced these richly detailed, intimate portraits and revealed exotic, mysterious landscapes unlike anything we’ve ever seen.”

Engineering Feats

Dawn is the only spacecraft to orbit a body in the asteroid belt. And it is the only spacecraft to orbit two extraterrestrial destinations. These feats were possible thanks to ion propulsion, a tremendously efficient propulsion system familiar to science-fiction fans and space enthusiasts. Dawn pushed the limits of the system’s capabilities and stamina, showing how useful it is for other missions that aim to visit multiple destinations.

Pushed by ion propulsion, Dawn reached Vesta in 2011 and investigated it from surface to core during 14 months in orbit. In 2012, engineers maneuvered Dawn out of orbit and steered it though the asteroid belt for more than two years before inserting it into orbit around the dwarf planet Ceres, where it has been collecting data since 2015.

Window into the Past

All the while, scientists gained new insight into the early stages of our Solar System, fulfilling Dawn’s objective. The mission was named for its purpose: to learn more about the dawn of the Solar System. It targeted Ceres and Vesta because they function as time capsules, intact survivors of the earliest part of our history. And the duo delivered, giving scientists insight into the original building blocks of the Solar System.

“Vesta and Ceres have each told their story of how and where they formed, and how they evolved — a fiery magmatic history that led to rocky Vesta and a cooler, water-rich history that resulted in the ancient ocean world Ceres,” said Carol Raymond of JPL, principal investigator of the Dawn mission. “These treasure troves of information will continue to help us understand other bodies in the Solar System far into the future.”

Spectacular Ceres

There was so much that scientists didn’t know about Ceres before Dawn arrived. Raymond wondered whether they might find Ceres covered with a smooth, young surface — an enormous cue ball with a frozen crust. Instead, they found the dwarf planet wearing the chemistry of its old ocean. “What we found was completely mind-blowing. Ceres’ history is just splayed all over its surface,” she said.

Some of the dazzling bright spots turned out to be brilliant salty deposits, composed mainly of sodium carbonate that made its way to the surface in a slushy brine from within or below the crust.

The findings reinforce the idea that dwarf planets, not just icy moons like Enceladus and Europa, could have hosted oceans during their history — and potentially still do. Analyses from Dawn data suggest there may still be liquid under Ceres’ surface and that some regions were geologically active relatively recently, feeding from a deep reservoir.

One of Dawn’s biggest reveals on Ceres lay in the region of Ernutet Crater. Organic molecules were found in abundance. Organics are among the building blocks of life, though Dawn’s data can’t determine if Ceres’ organics were formed by biological processes.

“There is growing evidence that the organics in Ernutet came from Ceres’ interior, in which case they could have existed for some time in the early interior ocean,” said Julie Castillo-Rogez, Dawn’s project scientist and deputy principal investigator at JPL.

Vibrant Vesta

At Vesta, Dawn’s investigation into the early Solar System found a 4.5-billion-year-old witness it could interrogate. Dawn mapped the craters of the planet-like world and revealed that its northern hemisphere had experienced more large impacts than expected, suggesting there were more large objects in the asteroid belt early on than scientists thought.

Vesta held other surprises as well. While it’s technically classified as an asteroid, that label belies the rich and varied terrain Dawn revealed, and the planet-like processes that Vesta experienced. Hubble had relayed images of a mountain at the center of an enormous basin now called Rheasilvia. Dawn’s mapping showed it to be twice the height of Mt. Everest, and it revealed canyons that rival the Grand Canyon in size. Dawn also confirmed Vesta as the source of a very common family of meteorites.

Now, near the end of Dawn’s second extended mission at Ceres, the spacecraft has continued to gather high-resolution images, gamma ray and neutron spectra, infrared spectra, and gravity data. Almost once a day, it will swoop over Ceres about 22 miles (35 kilometers) from its surface — only about three times the altitude of a passenger jet — gathering valuable data until it expends the last of the hydrazine that feeds thrusters controlling its orientation. Dawn’s reaction wheels failed earlier in the mission, leaving it heavily dependent on this key fuel. When Dawn runs out in the next month or two, the spacecraft will lose its ability to communicate with Earth, but it must not crash into Ceres.

Because Ceres has conditions of interest to scientists who study chemistry that leads to the development of life, NASA follows strict planetary protection protocols for the disposal of the Dawn spacecraft. Unlike Cassini, which deliberately plunged into Saturn’s atmosphere to protect the system from contamination — Dawn will remain in orbit around Ceres, which has no atmosphere.

Engineers designed Dawn’s final orbit to ensure it will not crash for at least 20 years — and likely decades longer.

Rayman, who led the team that flew Dawn throughout the mission and into its final orbit, likes to think of Dawn’s end this way: as “an inert, celestial monument to human creativity and ingenuity.”

More on Dawn’s mission legacy here: https://dawn.jpl.nasa.gov/mission/toolkit/

The Dawn mission is managed by JPL for NAPrSA’s Science Mission Directorate in Washington. Dawn is a project of the directorate’s Discovery Program, managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama. JPL is responsible for overall Dawn mission science. Northrop Grumman in Dulles, Virginia, designed and built the spacecraft. The German Aerospace Center, Max Planck Institute for Solar System Research, Italian Space Agency and Italian National Astrophysical Institute are international partners on the mission team.

For a complete list of mission participants, visit:

https://dawn.jpl.nasa.gov/mission

More information about Dawn is available at the following sites:

https://www.nasa.gov/dawn

https://dawn.jpl.nasa.gov

The panorama includes umber skies, darkened by a fading global dust storm. It also includes a rare view by the Mast Camera of the rover itself, revealing a thin layer of dust on Curiosity’s deck. In the foreground is the rover’s most recent drill target, named “Stoer” after a town in Scotland near where important discoveries about early life on Earth were made in lakebed sediments.

The new drill sample delighted Curiosity’s science team, because the rover’s last two drill attempts were thwarted by unexpectedly hard rocks. Curiosity started using a new drill method earlier this year to work around a mechanical problem. Testing has shown it to be as effective at drilling rocks as the old method, suggesting the hard rocks would have posed a problem no matter which method was used.

There’s no way for Curiosity to determine exactly how hard a rock will be before drilling it, so for this most recent drilling activity, the rover team made an educated guess. An extensive ledge on the ridge was thought to include harder rock, able to stand despite wind erosion; a spot below the ledge was thought more likely to have softer, erodible rocks. That strategy seems to have panned out, but questions still abound as to why Vera Rubin Ridge exists in the first place.

The rover has never encountered a place with so much variation in color and texture, according to Ashwin Vasavada, Curiosity’s project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California. JPL leads the Mars Science Laboratory mission that Curiosity is a part of.

“The ridge isn’t this monolithic thing — it has two distinct sections, each of which has a variety of colors,” Vasavada said. “Some are visible to the eye and even more show up when we look in near-infrared, just beyond what our eyes can see. Some seem related to how hard the rocks are.”

The best way to discover why these rocks are so hard is to drill them into a powder for the rover’s two internal laboratories. Analyzing them might reveal what’s acting as “cement” in the ridge, enabling it to stand despite wind erosion. Most likely, Vasavada said, groundwater flowing through the ridge in the ancient past had a role in strengthening it, perhaps acting as plumbing to distribute this wind-proofing “cement.”

Much of the ridge contains hematite, a mineral that forms in water. There’s such a strong hematite signal that it drew the attention of NASA orbiters like a beacon. Could some variation in hematite result in harder rocks? Is there something special in the ridge’s red rocks that makes them so unyielding?

For the moment, Vera Rubin Ridge is keeping its secrets to itself.

Two more drilled samples are planned for the ridge in September. After that, Curiosity will drive to its scientific end zone: areas enriched in clay and sulfate minerals higher up Mt. Sharp. That ascent is planned for early October.

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In “The Future of Nuclear Energy in a Carbon-Constrained World,” released by the MIT Energy Initiative (MITEI) on Sept. 3, the authors analyze the reasons for the current global stall of nuclear energy capacity — which currently accounts for only 5 percent of global primary energy production — and discuss measures that could be taken to arrest and reverse that trend.

The study group, led by MIT researchers in collaboration with colleagues from Idaho National Laboratory and the University of Wisconsin at Madison, is presenting its findings and recommendations at events in London, Paris, and Brussels this week, followed by events on Sept. 25 in Washington, and on Oct. 9 in Tokyo.

MIT graduate and undergraduate students and postdocs, as well as faculty from Harvard University and members of various think tanks, also contributed to the study as members of the research team.

“Our analysis demonstrates that realizing nuclear energy’s potential is essential to achieving a deeply decarbonized energy future in many regions of the world,” says study co-chair Jacopo Buongiorno, the TEPCO Professor and associate department head of the Department of Nuclear Science and Engineering at MIT. He adds, “Incorporating new policy and business models, as well as innovations in construction that may make deployment of cost-effective nuclear power plants more affordable, could enable nuclear energy to help meet the growing global demand for energy generation while decreasing emissions to address climate change.”

The study team notes that the electricity sector in particular is a prime candidate for deep decarbonization. Global electricity consumption is on track to grow 45 percent by 2040, and the team’s analysis shows that the exclusion of nuclear from low-carbon scenarios could cause the average cost of electricity to escalate dramatically.

“Understanding the opportunities and challenges facing the nuclear energy industry requires a comprehensive analysis of technical, commercial, and policy dimensions,” says Robert Armstrong, director of MITEI and the Chevron Professor of Chemical Engineering. “Over the past two years, this team has examined each issue, and the resulting report contains guidance policymakers and industry leaders may find valuable as they evaluate options for the future.”

The report discusses recommendations for nuclear plant construction, current and future reactor technologies, business models and policies, and reactor safety regulation and licensing. The researchers find that changes in reactor construction are needed to usher in an era of safer, more cost-effective reactors, including proven construction management practices that can keep nuclear projects on time and on budget.

“A shift towards serial manufacturing of standardized plants, including more aggressive use of fabrication in factories and shipyards, can be a viable cost-reduction strategy in countries where the productivity of the traditional construction sector is low,” says MIT visiting research scientist David Petti, study executive director and Laboratory Fellow at the Idaho National Laboratory. “Future projects should also incorporate reactor designs with inherent and passive safety features.”

These safety features could include core materials with high chemical and physical stability and engineered safety systems that require limited or no emergency AC power and minimal external intervention. Features like these can reduce the probability of severe accidents occurring and mitigate offsite consequences in the event of an incident. Such designs can also ease the licensing of new plants and accelerate their global deployment.

“The role of government will be critical if we are to take advantage of the economic opportunity and low-carbon potential that nuclear has to offer,” says John Parsons, study co-chair and senior lecturer at MIT’s Sloan School of Management. “If this future is to be realized, government officials must create new decarbonization policies that put all low-carbon energy technologies (i.e. renewables, nuclear, fossil fuels with carbon capture) on an equal footing, while also exploring options that spur private investment in nuclear advancement.”

The study lays out detailed options for government support of nuclear. For example, the authors recommend that policymakers should avoid premature closures of existing plants, which undermine efforts to reduce emissions and increase the cost of achieving emission reduction targets. One way to avoid these closures is the implementation of zero-emissions credits — payments made to electricity producers where electricity is generated without greenhouse gas emissions — which the researchers note are currently in place in New York, Illinois, and New Jersey.

Another suggestion from the study is that the government support development and demonstration of new nuclear technologies through the use of four “levers”: funding to share regulatory licensing costs; funding to share research and development costs; funding for the achievement of specific technical milestones; and funding for production credits to reward successful demonstration of new designs.

The study includes an examination of the current nuclear regulatory climate, both in the United States and internationally. While the authors note that significant social, political, and cultural differences may exist among many of the countries in the nuclear energy community, they say that the fundamental basis for assessing the safety of nuclear reactor programs is fairly uniform, and should be reflected in a series of basic aligned regulatory principles. They recommend regulatory requirements for advanced reactors be coordinated and aligned internationally to enable international deployment of commercial reactor designs, and to standardize and ensure a high level of safety worldwide.

The study concludes with an emphasis on the urgent need for both cost-cutting advancements and forward-thinking policymaking to make the future of nuclear energy a reality.

Further information: http://energy.mit.edu/research/future-nuclear-energy-carbon-constrained-world/

PhD candidate Daiki Sato and Professor Masakado Kawata have discovered SLC18A1 (VMAT1), which encodes vesicular monoamine transporter 1, as one of the genes evolved through natural selection in the human lineage. VMAT1 is mainly involved in the transport of neurochemicals, such as serotonin and dopamine in the body, and its malfunction leads to various psychiatric disorders. VMAT1 has variants consisting of two different amino acids, threonine (136Thr) and isoleucine (136Ile), at site 136.

Several studies have shown that these variants are associated with psychiatric disorders, including schizophrenia, bipolar disorder, anxiety, and neuroticism (a personality trait). It has been known that individuals with 136Thr tend to be more anxious and more depressed and have higher neuroticism scores. They showed that other mammals have 136Asn at this site but 136Thr had been favored over 136Asn during human evolution. Moreover, the 136Ile variant had originated nearly at the Out-of-Africa migration, and then, both 136Thr and 136Ile variants have been positively maintained by natural selection in non-African populations.

The study by Sato and Kawata indicates that natural selection has possibly shaped our psychiatric traits and maintained its diversity. The results provide two important implications for human psychiatric evolution. First, through positive selection, the evolution from Asn to Thr at site 136 on SLC18A1 was favored by natural selection during the evolution from ancestral primates to humans, although individuals with 136Thr are more anxious and have more depressed minds.

Second, they showed that the two variants of 136Thr and 136Ile have been maintained by natural selection using several population genetic methods. Any form of natural selection that maintains genetic diversity within populations is called “balancing selection.” Individual differences in psychiatric traits can be observed in any human population, and some personality traits are also found in non-human primates. This suggests the possibility that a part of genetic diversity associated with personality traits and/or psychiatric disorders are maintained by balancing selection, although such selective pressure is often weak and difficult to detect.

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“In the past century, memory research focused primarily on understanding how information can be successfully remembered,” says Nikolai Axmacher, Head of the Neuropsychology Department in Bochum. “However, forgetting is crucial for emotional wellbeing, and it enables humans to focus on a task.”

Rhythmic brain activity and word test

The researchers recorded the brain activity of 22 patients, who had electrodes implanted either in the prefrontal cortex or in a deeper structure, the hippocampus. They presented the participants with a number of words, asking them either to remember or to forget them. A test showed that the participants did indeed remember the words that they were supposed to forget less well than the words they were supposed to remember.

As they conducted the analysis, the researchers payed close attention to the synchronous rhythmic activity in the hippocampus and the prefrontal cortex. During active forgetting, oscillations in both areas of the brain showed characteristic changes in specific frequency bands. In the prefrontal cortex, oscillations between three and five Hertz were more pronounced, i.e. in the so-called theta range. They were coupled with increased oscillations at higher frequencies, namely between 6 and 18 Hertz, in the hippocampus.

The forgetting frequency

“The data showed us that during active forgetting, the activity in the hippocampus, an important region for memory, is regulated by the prefrontal cortex,” explains Carina Oehrn, who was initially involved in the research project in Bochum and now works at the University Hospital in Marburg. “The activity in the hippocampus is not just suppressed; rather, it is switched to a different frequency, in which currently processed information is no longer encoded,” continues the neuroscientist.

Potential therapy approach for posttraumatic stress disorder

The team believes that research into voluntary forgetting might constitute the basis of potential new therapies of posttraumatic stress disorder, which causes patients to relive negative emotional memories again and again.

“The prefrontal cortex, i.e. the brain region that exerts active control over memory processes, may be activated for therapy purposes through non-invasive magnetic or electrical stimulation,” as Oehrn outlines an initial idea. “Still, the benefits of this treatment will have to be tested in future studies.”

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Their new technique is the most sensitive way of controlling a chemical reaction on some of the smallest scales scientists can work — at the single molecule level. It will open up research possibilities across the fields of nanoscience and nanophysics.

An experiment at the extreme limit of nanoscience called “STM (scanning tunnelling microscope) molecular manipulation” is often used to observe how individual molecules react when excited by adding a single electron.

A traditional chemist may use a test-tube and a Bunsen burner to drive a reaction; here they used a microscope and its electrical current to drive the reaction. The current is so small it is more akin to series of individual electrons hitting the target molecule. But this whole experiment is a passive process- once the electron is added to the molecule researchers only observe what happens.

But when Dr Kristina Rusimova reviewed her data from the lab while on holiday, she discovered some anomalous results in a standard experiment, which on further investigation couldn’t be explained away. When the electric current is turned up, reactions always goes faster, except here it didn’t.

Dr Rusimova and colleagues spent months thinking of possible explanations to debunk the effect, and repeating the experiments, but eventually realised they had found a way to control single-molecule experiments to an unprecedented degree, in new research published in Science.

The team discovered that by keeping the tip of their microscope extremely close to the molecule being studied, within 600-800 trillionths of a metre, the duration of how long the electron sticks to the target molecule can be reduced by over two orders of magnitude, and so the resulting reaction, here driving individual toluene molecules to lift off (desorb) from a silicon surface, can be controlled.

The team believes this is because the tip and molecule interact to create a new quantum state, which offers a new channel for the electron to hop to from the molecule, hence reducing the time the electron spends on the molecule and so reducing the chances of that electron causing a reaction.

At its most sensitive this means the time of the reaction can be controlled for its natural limit to 10 femtoseconds down to just 0.1 femtoseconds.

Dr Rusimova said: “This was data from an utterly standard experiment we were doing because we thought we had exhausted all the interesting stuff — this was just a final check. But my data looked ‘wrong’ — all the graphs were supposed to go up and mine went down. “

Dr Peter Sloan, lead author on the study, added: “If this was correct, we had a completely new effect but we knew if we were going to claim anything so striking we needed to do some work to make sure it’s real and not down to false positives.”

“I always think our microscope is a bit like the Millennium Falcon, not too elegant, held together by the people who run it, but utterly fantastic at what it does. Between Kristina and PhD student Rebecca Purkiss the level of spatial control they had over the microscope was the key to unlocking this new physics.”

Dr Sloan added: “The fundamental aim of this work is to develop the tools to allow us to control matter at this extreme limit. Be it breaking chemical bonds that nature doesn’t really want you to break, or producing molecular architectures that are thermodynamically forbidden. Our work offers a new route to control single molecules and their reaction. Essentially we have a new dial we can set when running our experiment. The extreme nature of working on these scales makes it hard to do, but we have extreme resolution and reproducibility with this technique.”

The team hopes that their new technique will open the door for lots of new experiments and discoveries at the nanoscale, thanks to the options that it provides for the first time.

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Without the threat of predators and with food provided, it’s easy to imagine they would just stand on one leg, snoozing.

But research by the University of Exeter shows captive flamingos do more foraging and roam more widely in their enclosure at night than in the day.

“For lots of species housed in zoological collections, we know little about what they do once their keepers go home,” said Dr Paul Rose, of the University of Exeter.

“Wild flamingos are more active at night, and we were surprised to find the same is true in captivity.

“It seems they have an in-built behaviour pattern to keep active.

“This research has important implications for how we manage zoo populations of flamingos and other species.

“By providing a habitat that allows a range of activities to be performed — including some we don’t see them doing in the daytime — we can allow them to behave in a natural way.”

More research into nocturnal behaviour is needed if the welfare of captive animals is to be fully understood, Dr Rose says.

This study used remote trail cameras, fitted around the enclosure of a large flock of about 270 greater flamingos at WWT Slimbridge Wetland Centre.

The results showed flamingo foraging peaked in the evening, meaning this natural timing persisted despite the fact the birds were provided with a complete diet in the daytime.

Flamingos roamed most widely in their enclosure during the later evening, middle of the night and into the early morning.

Birds congregated in fewer areas of their habitat during the later morning and middle of the day — preferring to be in one specific place for resting and preening.

Some behaviours, such as courtship displays, were most commonly performed during the day.

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“It may seem almost inconceivable that just one single gene should make all the difference,” Libbrecht pointed out. The researchers drew their conclusion from a comparison of 5,581 genes in seven ant species in four different subfamilies that differ from each other with regard to numerous characteristics. But in one thing are they all alike: there is always a greater expression of ILP2 in the brain of reproductive insects. Queens thus have higher levels than workers. A further finding indicates that this peptide is found only in the brain, where it is produced in a small cluster of just 12 to 15 cells.

Division of reproduction and brood care as the basis of social colony formation

It is postulated that the origins of social behavior in insects are to be found in wasp-like ancestors that alternated between reproduction and brood care phases. A female wasp would lay an egg and take care of the larva until it pupated. However, these two phases were separated and their associated duties assigned to different individuals, namely queens and workers, during the evolution of eusociality.

Libbrecht and his colleagues in New York City investigated the ant species Ooceraea biroi to determine the molecular mechanisms underlying this division of labor. O. biroi is a small species of 2 to 3 millimeters in length that originated from Asia but has spread throughout the tropics. The insects live in underground passages, attack the nests of other ant species, and feed on their brood. The unusual thing about the O. biroi species is that there are no queens, only female workers. However, every female worker can reproduce through parthenogenesis. This means that a female produces another identical female — the insects in effect clone themselves. And they always follow a specific cycle: all female workers lay eggs during an 18-day period, after which they spend 16 days gathering food and feeding the larvae. The cycle then begins once again.

This cyclical behavior is comparable to that of the solitary wasp-like ancestors and is controlled by the presence of larvae. When the first larvae hatch at the end of the reproductive phase, their presence suppresses ovarian activity and triggers brood care behavior. When the larvae begin pupation at the end of the brood care phase, ovarian activity is scaled up and foraging scaled back. “What we did was break this cycle,” explained Libbrecht. The researchers synthesized the peptide ILP2 and injected it into the ants. This caused the ants to lay eggs in the presence of larvae.

Libbrecht used a brood substitution approach to investigate what happens when larvae are introduced into the colony during the reproductive phase and, conversely, when they are removed during the brood care phase. “What we see is that gene expression in the brain changes in both phases and the ants change their behavior and physiology accordingly. This response, however, happens at a faster rate if we confront egg-laying ants with larvae.” The insects then stop laying eggs and start to care for the brood. “This does make sense. It is, after all, important for survival to quickly start feeding the larvae,” he added. This experiment also revealed that the expression of ILP2 in the brain changed quickly and significantly in response to the change in social conditions.

From asymmetry in nutrition to asymmetry in reproduction

The researchers also considered the relevance of nutrition, which is known to be of importance when it comes to the differentiation between queens and workers. A large quantity or a good quality of nutritional protein favors the development of female larvae into queens. In colonies of the species O. biroi, a small proportion of the ants are so-called intercastes. These insects are slightly bigger, have eyes, and are more reproductive. Because of this, they can be compared to some extent with normal queens. The probability of a larva becoming an intercaste increases if it receives better nourishment. Fluorescence imaging shows that these intercastes have more ILP2 in their brains than normal workers.

“Something comparable may well have taken place in the case of the ancestors of eusocial insects,” Dr. Romain Libbrecht suggested. “Perhaps a minor asymmetry with regard to nutrition of larvae led to asymmetry in the reproductive behavior of adults developing from those larvae.” The assumption that the division into queens and workers might therefore have commenced with one single difference is supported by experiments conducted in a total of seven different ant species.

Further research is to be undertaken to determine whether the findings also apply to other social insects and how ant colonies as superorganisms control the overall supply of nutrition.

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