Leafcutter ants, new research


This 2015 video is called Leafcutter Ants‘ Life.

From Rice University in the USA:

Leafcutter ants‘ success due to more than crop selection

Genetic analysis finds leafcutter ants originated in South America

May 9, 2018

A complex genetic analysis has biologists re-evaluating some long-held beliefs about the way societies evolved following the invention of agriculture — by six-legged farmers.

Like humans, leafcutter ants grow crops, and like humans, farming allows the ants to produce enough food to support millions of individuals who work at specialized jobs. But while people invented agriculture at the dawn of civilization about 10,000 years ago, leafcutters began cultivating massive subterranean fungus gardens more than 10 million years ago.

In a study published this week in Molecular Ecology, biologists from Rice University, the University of Texas at Austin (UT Austin) and Brazil’s São Paulo State University analyzed genetic data from samples collected at leafcutter nests throughout South, Central and North America and concluded that the ants originated in South America and owe their success to something more than their choice of crops.

The ability to grow domesticated crops was a major turning point in human history and evolution, and we thought, until recently, that a similar thing was true for leafcutters,” said study co-author Scott Solomon, an evolutionary biologist at Rice who collected many of the study’s samples as a graduate student and postdoctoral researcher at UT Austin and the Smithsonian Institution in Washington, D.C. “Our findings suggest that several of the things we thought we ‘knew’ about leafcutters are not true.”

The research, led by co-author Ulrich Mueller, Solomon’s longtime UT collaborator and mentor, is available in both the newly published paper and a 2017 companion study, also published in Molecular Ecology.

“This study started 20 years ago as a collaboration between Brazilian and Texan labs and developed into a huge collaboration involving 22 labs surveying leafcutter ants in 17 countries,” said Mueller, the William Morton Wheeler-Lost Pines Professor in UT Austin’s Department of Integrative Biology. “Because of this international effort, we now have a comprehensive understanding of leafcutter ecology and evolution.”

Leafcutter ants are found only in the Americas. More than 40 species range from Argentina to the southern United States, and they are a dominant ecological player in any forest or grassland they inhabit.

“They aren’t the only ants that grow fungi, but if you compare leafcutter ants with other ants that grow fungi, there are many differences,” Mueller said. “For starters, no other ants use freshly cut leaves to grow their fungi.”

Ants that grow fungus on dead and decaying leaves have been around even longer than leafcutters, probably about 50 million years, Solomon said. But leafcutters’ ability to use living leaves was a quantum leap in evolutionary terms because it opened up the entire ecosystem. For example, Solomon said, the ability to consume plant matter they cannot directly digest allows a nest of leafcutters to consume about as much vegetation each year as a full-grown cow.

“Once you can use fresh leaves, it gives you access to so much more food,” Solomon said. “If you can grow and raise your crop on any leaf that’s growing out there, then the sky’s the limit.”

In comparison with other fungus-growing ants, leafcutter colonies are enormous, Solomon said. “They’re on the order of millions of individuals. Some leafcutter colonies are so large that they show up on photos taken by satellites in space.”

Leafcutters also have specialized tasks. Individual worker ants come in different sizes, and they have different jobs.

“Some are specialized on raising the young,” Solomon said. “Others are specialized on removing weeds and disease inside the nest. Others are specialized on going out and finding food, and yet others are specialized on defending the colony.

“All of the specialization is unique to the leafcutters,” he said. “With other fungus-growing ants, the workers are basically interchangeable. They don’t have these specialized tasks.

“One of the long-held truths of our field was that leafcutters grow a special and unique kind of fungus that no other ant could grow,” Solomon said. “It was thought that something about that unique crop allowed them to do these things that other fungus-growing ants couldn’t do.”

The new studies, which are the first to analyze the genes of fungi from hundreds of leafcutter colonies across the Americas, found instances where other ants grew the specialized “leafcutter-only” fungus, as well as instances where leafcutters grew more generic fungal crops.

“It’s not the crop that makes them special,” Mueller said. “We found that leafcutter ants and their fungi have co-evolved, and while that’s not a surprise, the evidence suggests that this co-evolution occurred in a more complex way than previously believed.

“For example, we found that the type of fungi that was long thought to be unique to leafcutters can be grown by other ants on dead plant material,” he said. “In one case, it’ll be grown on fresh vegetation, and in another case, it won’t.”

Solomon said, “The question is what gives this fungus the ability to digest freshly cut leaves? It’s not something that is inherent in the fungus. There seems to be something about the way the leafcutter ants are cultivating the fungus that gives it that ability.”

Solomon began collecting leaf-cutting ants and their fungi in Central America in 2002 as a graduate student in Mueller’s lab. In 2007 Solomon expanded his work, thanks to a National Science Foundation (NSF) international postdoctoral fellowship that allowed him to spend a year working with study co-author Mauricio Bacci Jr. at São Paulo State University in Rio Claro, Brazil. Solomon’s samples and dozens of others gathered over the years by Mueller’s and Bacci’s teams allowed the researchers to pinpoint the origin of leafcutters to South America, probably in the grassland plains of what is now southern Brazil and Argentina, Solomon said.

“We sampled tons of different nests of leafcutter ant species throughout the entire range of all leafcutters, which goes from Texas in the extreme north down to Argentina,” Solomon said. “What’s novel about our approach is how much sampling there was, particularly in South America. In the past, there has been a lot of sampling, but it was focused in just a few different regions, particularly in Costa Rica and Panama.

“It turns out the leafcutters in those places don’t represent species that live elsewhere,” he said. “By going and sampling in other places, especially in the open grasslands of southern Brazil, Paraguay and northern Argentina, we were able to show that the greatest genetic diversity of leafcutter fungi is in South America. Usually, wherever there’s the greatest genetic diversity is where a group originated. That is true for humans, and that’s just generally true of other species, and that leads us to believe the leafcutters originated in the grasslands of South America.”

Mueller said, “The study illustrates the importance in science of re-evaluating entrenched assumptions, amassing large data sets and collaborating internationally before reaching conclusions.”

Ants working together to carry a large piece of food get around obstacles by switching between two types of motion: one that favors squeezing the morsel through a hole and another to seek a path around the barrier: here.

Ants provide clues to why biodiversity is higher in the tropics. New global data of invertebrate distributions suggests time holds key to species diversity: here.

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Ants atlas published in the Netherlands


This 2015 video says about itself:

TOP 10: Most Impressive Ants On The Planet

Cardiocondyla obscurior
Temnothorax pilagens
Cephalotes specularis
Dinoponera quadriceps
Nylanderia fulva

Cardiocondyla obscurior is a tropical ant species. Still, it lives at one place in the temperate climate Netherlands: in the tropical hothouses of the botanical garden in Leiden. It will not spread from there to the outside, which is too cold.

Recently, a new atlas about ant species in the Netherlands was published, called Ecologische atlas Nederlandse mieren (Hymenoptera: Formicidae). It shows where the various species live.

There are 68 native Dutch ant species; 29 of them are threatened. Eg, Camponotus vagus has only one nest in the Netherlands.

The black garden ant is the most common species in the Netherlands.

There are 36 invasive ant species in the Netherlands. Only seven of them live outside buildings; the others live only inside, where it is warmer.

Hurricane Harvey disaster and ants in Texas


This video from the USA says about itself:

31 August 2017

To survive Texas floods, fire ant colonies join to form floating masses that act like a raft.

From Rice University in the USA:

Are fire ants worse this spring because of Hurricane Harvey?

Ecologists are checking to see if floods gave advantage to invasive ants

March 26, 2018

Rice University ecologists are checking to see if Hurricane Harvey’s unprecedented floods gave a competitive boost to fire ants and crazy ants, two of southeast Texas’ least favorite uninvited guests.

Extreme weather events like Harvey are expected to become more likely as Earth’s climate changes due to greenhouse gas emissions, and scientists don’t understand how extreme weather will impact invasive pests, pollinators and other species that affect human well-being.

With support from the National Science Foundation’s Rapid Response Research (RAPID) program, Rice ecologists Tom Miller, Sarah Bengston and Scott Solomon, along with their students, are evaluating whether Harvey increased opportunities for invasion by exotic ants.

Hurricane Harvey was, among other things, a grand ecological experiment”, said Miller, the principal investigator on the grant and the Godwin Assistant Professor of Ecology and Evolutionary Biology in Rice’s Department of BioSciences. “It offers a unique opportunity to explore whether a single extreme-weather event can re-shuffle an entire community of organisms.”

“We’re conducting monthly pitfall sampling at 19 established sites in the Big Thicket, a national preserve near Beaumont”, said Bengston, an ant expert, co-principal investigator on grant and Huxley Research Instructor of BioSciences. “Rice’s team has been working at these same sites for three years, and we know fire ants and tawny crazy ants, which are each invasive species, had begun to penetrate the intact native ecosystems in the park before the hurricane. We now want to know whether Harvey accelerated this invasion process.”

The RAPID funding will allow the team to document changes in ant communities and test whether changes in response to the hurricane are transient or represent new stable states.

Miller said the researchers also plan to assemble a functional trait database for the ant communities to test whether the Harvey floodwaters favored some types of ant species — such as those with larger bodies or more-protected nests — over others.

“There are dozens of native ant species in the preserve that provide valuable ecosystem services like decomposition and pest control”, said Solomon, an ant expert, co-principal investigator on the grant and associate teaching professor of biosciences. “Fire ants and crazy ants, which are each native to South America, are noxious invasive pests that tend to overwhelm and drive out almost all native ant species. If the floods cleaned the slate by drowning all the native ant colonies in the area, our hypothesis is that this may provide a competitive advantage to invaders.”

Solomon said research teams began making monthly visits to the Big Thicket test sites just a few weeks after Harvey and will continue collecting samples for one year.

“It was a cold winter, and there wasn’t much ant activity,” he said. “As temperatures warm up, we’ll be interested to see which ants come back the soonest and in what numbers.”

NSF’s RAPID grants support research of natural disasters and unanticipated events for which time is a factor in gathering data.

Record-hot Gulf of Mexico waters supercharged Hurricane Harvey, fueling it with vast stores of water and setting the stage for devastating flooding after it stalled near Houston: here.

How ants build bridges


This video says about itself:

See How Ants Build Bridges in Mid-Air With Just Their Bodies | National Geographic

22 March 2018

Army ants exhibit complex social behaviors that require group cooperation to achieve success.

Ants’ health care system


This video says about itself:

Self-Sacrificing Ants Refuse Treatment of Their Wounds | National Geographic

20 February 2018

A new study reveals that after a raid on a termite nest, the injured [Matabele] ants are cared for by their comrades.

Navy Seals abide by a code that no man is left behind. Termite-hunting ants abide by a similar code. A new study reveals that after a raid on a termite nest, the injured ants are cared for by their comrades.

If kept by themselves, 80 percent of injured ants died. But if cared for by their nest-mates for even an hour, only a tenth died.

Another finding of the study reveals how the ants prioritize who gets cared for and who doesn’t. In human health care, doctors decide which patients need to be helped the most. With ants, it’s the exact opposite. The injured ants themselves decide if they should be treated or not.

When no help was in sight, injured ants made a beeline for the nest. But when nest-mates were near, they stumbled and fell, appearing “more injured” as a way to attract aid. But the ants play up their injuries only if they sensed that their problems were minor enough to be treated. If ants were mortally injured, they refused to cooperate, flailing their legs around when probed or picked up, forcing their helpers to abandon them.

The mortally wounded ants choose to die rather than have energy and resources wasted on their futile rehabilitation. This discovery marks the first time non-human animals have been observed systematically nursing their wounded back to health. Read more in “‘Paramedic’ Ants Are the First to Rescue and Heal Their Wounded Comrades”.

Termites are the African Matabele ants’ (Megaponera analis) favourite dish. Proceeding in long files of 200 to 600, they raid termites at their foraging sites and haul the prey back to their nest where they are ultimately eaten. Before starting their raids, the ants send out scouts to look for the termites’ foraging sites. Once they have spotted them, the scout ants return to the nest to mobilize their comrades. On their way back to the nest, the scouts show astonishing navigational abilities: They take the quickest route rather than the shortest: here.

Ants named after Obama, Ken Saro-Wiwa


This 23 August 2017 video is called 3D rotation video of Zasphinctus sarowiwai sp. n. paratype worker.

From the Okinawa Institute of Science and Technology (OIST) Graduate University in Japan:

Say hello to the 3-D Obama ant

Three new ant species named in honor of key figures in conservation — Barack Obama, Ken Saro-Wiwa, and E.O. Wilson — are immortalized as 3-D virtual avatars

August 30, 2017

Biologists at the Okinawa Institute of Science and Technology Graduate University (OIST) have named three new, rare ant species in Africa after important figures in African biodiversity conservation — a former United States president, a writer-activist, and a world-renowned scientist. Using new scanning technology for documenting species, the OIST researchers compiled scans of the ants to create 3D avatars, giving them, and their namesakes, a measure of immortality.

The first ant species, Zasphinctus obamai, was discovered in the Kakamega Forest National Park, Kenya, located near Mr. Barack Obama’s ancestral family village. The OIST researchers chose to honor Mr. Obama for his prodigious contributions to global biodiversity conservation. The second species, Zasphinctus sarowiwai, was named after Ken Saro-Wiwa, a Nigerian writer and environmental activist who, after campaigning against irresponsible oil development, was executed in 1995. The third, Zasphinctus wilsoni, was named after biologist Edward O. Wilson, who is famous for his contributions to sociobiology, ant biology, evolution, and biodiversity conservation. Through his foundation, Wilson has contributed to the resurgence of Gorongosa National Park in Mozambique, which is one of Africa’s most successful wildlife restoration stories.

To create the 3D avatars, “we used X-ray microtomography, or micro-CT, which is comparable to when you go to the doctor and get a CT scan but at much higher resolution, to scan very small insects,” explains Dr. Francisco Hita Garcia, first author on the study and a member of the Biodiversity and Biocomplexity Unit at OIST.

The OIST research team then compiled the scans into 3D reconstructions of the ants — identical to their originals down to the thinnest hair on the tiniest leg. The reconstructions hint at a future of virtual taxonomy with the potential to alleviate issues of time, money, and specimen damage, and realize new horizons of inquiry into hard-to-reach details, such as the thickness of an ant’s exoskeleton.

The following shows an interactive model of a whole-body 3D reconstruction of the Obama ant: Zasphinctus obamai.

This 23 August 2017 video is called 3D rotation video of Zasphinctus obamai sp. n. holotype worker.

It is an exact replica of a physical specimen that the OIST researchers collected during field work in the Kakamega Forest in Western Kenya and scanned using micro-CT.

There are plenty of advantages to creating these models. For example, since they are made using micro-CT technology, the original, physical specimens are recreated on both the outside and inside. As such, if researchers wanted to study the way the inside of an ant’s mouth is organized, they could simply virtually remove the outside parts that are in the way — something that cannot be done on a physical specimen without damaging it. In their study, the OIST researchers did precisely this.

In addition to reconstructing and examining the ants’ mouthparts, the OIST researchers also visualized the muscles inside of the ants’ bodies and measured the thickness of their skin, called the cuticle, all with the help of the virtually reconstructed 3D models.

“We saw things that nobody ever looked at,” Dr. Hita Garcia explains, and through those new observations the research team was able to confirm details about the ants’ lifestyles. Other species of Zasphinctus from outside Africa are known to be predators of other ants, and the mouthparts, musculature, and skin-thickness data from the OIST researchers’ study all provide evidence that the African Zasphinctus ants are top predators as well. “Normally when you describe a new species, you don’t know much about its biology,” Dr. Hita Garcia explains, but with the 3D reconstructions researchers can discover details right away.

Another advantage of 3D models is that they can be easily accessed from anywhere. Especially for specimens that are rare, examining them requires a lot of time and money to coordinate — such as an expensive plane ticket to visit a museum in Nairobi. This is not the case with the 3D models. “If someone wants to see the Obama ant, they can download it, look at it, and 3D print it,” Dr. Hita Garcia explains.

Yet despite advances in scanning capabilities, the world of virtual taxonomy is not yet ready to be realized. For one, there are not enough research labs and institutes that provide access to micro-CT scanners. “We have millions of species on the planet, but we have 3D models for only a handful,” Dr. Hita Garcia explains. The technology is ready, the scientific community just needs the means and incentive to apply it, as well as to embrace it.

Until that future arrives, however, the OIST researchers can focus on using the unique names of the three new ants for altruistic purposes. “Since these ants are from very threatened habitats in Africa, we wanted to pick names that draw attention to the environment, and not just the ants,” Dr. Hita Garcia explains. The rainforests in equatorial Africa, as well as the savannah in Mozambique, needs to be protected before the habitats and animals living within them are destroyed.

In every animal community, several species in the same group share habitats. An international team has chosen ants to create the largest public-access database on the cohabitation of these insects. The goal is to understand their tricks for coexistence and how they respond to invasive species and climate change: here.

Cataglyphis fortis desert ants can learn visual or olfactory cues to pinpoint their nest, but only if these cues are unique to specify the nest entrance. Scientists from the Max Planck Institute for Chemical Ecology in Jena, Germany, discovered that the insects ignore visual landmarks or odors as nest-defining cues, if these occur not only near the nest but also along the route. Hence, ants are able to evaluate the informative value of such cues and are not fooled by ubiquitous unreliable cues: here.

Small ant transports big dead beetle


This 10 August 2017 video is about a small ant transporting a big dead beetle.

Ants are strong.

Carin van Dodewaard from the Netherlands made this video.