Biology

this-elephant-figured-out-how-to-use-a-hose-to-shower

This elephant figured out how to use a hose to shower

animal behavior, animal cognition, animal tool use, animals, Biology, elephants, Science / /

And the hose-showering behavior was “lateralized,” that is, Mary preferred targeting her left body side more than her right. (Yes, Mary is a “left-trunker.”) Mary even adapted her showering behavior depending on the diameter of the hose: she preferred showering with a 24-mm hose over a 13-mm hose and preferred to use her trunk to shower rather than a 32-mm hose.

It’s not known where Mary learned to use a hose, but the authors suggest that elephants might have an intuitive understanding of how hoses work because of the similarity to their trunks. “Bathing and spraying themselves with water, mud, or dust are very common behaviors in elephants and important for body temperature regulation as well as skin care,” they wrote. “Mary’s behavior fits with other instances of tool use in elephants related to body care.”

Perhaps even more intriguing was Anchali’s behavior. While Anchali did not use the hose to shower, she nonetheless exhibited complex behavior in manipulating the hose: lifting it, kinking the hose, regrasping the kink, and compressing the kink. The latter, in particular, often resulted in reduced water flow while Mary was showering. Anchali eventually figured out how to further disrupt the water flow by placing her trunk on the hose and lowering her body onto it. Control experiments were inconclusive about whether Anchali was deliberately sabotaging Mary’s shower; the two elephants had been at odds and behaved aggressively toward each other at shower times. But similar cognitively complex behavior has been observed in elephants.

“When Anchali came up with a second behavior that disrupted water flow to Mary, I became pretty convinced that she is trying to sabotage Mary,” Brecht said. “Do elephants play tricks on each other in the wild? When I saw Anchali’s kink and clamp for the first time, I broke out in laughter. So, I wonder, does Anchali also think this is funny, or is she just being mean?

Current Biology, 2024. DOI: 10.1016/j.cub.2024.10.017  (About DOIs).

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fungi-may-not-think,-but-they-can-communicate

Fungi may not think, but they can communicate

Biology, food, fungi, networks, nutrients, Science / /

Because the soil layer was so thin, most hyphae, which usually grow and spread underground by releasing spores, were easily seen, giving the researchers an opportunity to observe where connections were being made in the mycelium. Early hyphal coverage was not too different between the X and circle formations. Later, each showed a strong hyphal network, which makes up the mycelium, but there were differences between them.

While the hyphal network was pretty evenly distributed around the circle, there were differences between the inner and outer blocks in the X arrangement. Levels of decay activity were determined by weighing the blocks before and after the incubation period, and decay was pretty even throughout the circle, but especially evident on the four outermost blocks of the X. The researchers suggest that there were more hyphal connections on those blocks for a reason.

“The outermost four blocks, which had a greater degree of connection, may have served as “outposts” for foraging and absorbing water and nutrients from the soil, facilitated by their greater hyphal connections,” they said in the same study.

Talk to me

Fungal mycelium experiences what’s called acropetal growth, meaning it grows outward in all directions from the center. Consistent with this, the hyphae started out growing outward from each block. But over time, the hyphae shifted to growing in the direction that would get them the most nutrients.

Why did it change? Here is where the team thinks communication comes in. Previous studies found electrical signals are transmitted through hyphae. These signals sync up after the hyphae connect into one huge mycelium, much like the signals transmitted among neurons in organisms with brains. Materials such as nutrients are also transferred throughout the network.

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bats-use-echolocation-to-make-mental-maps-for-navigation

Bats use echolocation to make mental maps for navigation

bats, Behavioral science, Biology, echolocation, navigation, neurobiology, Science / /

Bat maps

To evaluate the route each bat took to get back to the roost, the team used their simulations to measure the echoic entropy it experienced along the way. The field where the bats were released was a low echoic entropy area, so during those first few minutes when they were flying around they were likely just looking for some more distinct, higher entropy landmarks to figure out where they were. Once they were oriented, they started flying to the roost, but not in a straight line. They meandered a bit, and the groups with higher sensory deprivation tended to meander more.

The meandering, researchers suspect, was due to trouble the bats had with maintaining the steady path relying on echolocation alone. When they were detecting distinctive landmarks like a specific orchard, they corrected the course. Repeating the process eventually brought them to their roost.

But could this be landmark-based navigation? Or perhaps simple beaconing, where an animal locks onto something like a distant light and moves toward it?

The researchers argue in favor of cognitive acoustic maps. “I think if echolocation wasn’t such a limited sensory modality, we couldn’t reach a conclusion about the bats using cognitive acoustic maps,” Goldshtein says. The distance between landmarks the bats used to correct their flight path was significantly longer than echolocation’s sensing range. Yet they knew which direction the roost was relative to one landmark, even when the next landmark on the way was acoustically invisible. You can’t do that without having the area mapped.

“It would be really interesting to understand how other bats do that, to compare between species,” Goldshtein says. There are bats that fly over a thousand meters above the ground, so they simply can’t sense any landmarks using echolocation. Other species hunt over sea, which, as per this team’s simulations, would be just one huge low-entropy area. “We are just starting. That’s why I do not study only navigation but also housing, foraging, and other aspects of their behavior. I think we still don’t know enough about bats in general,” Goldshtein claims.

Science, 2024.  DOI: 10.1126/science.adn6269

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these-hornets-break-down-alcohol-so-fast-that-they-can’t-get-drunk

These hornets break down alcohol so fast that they can’t get drunk

alcohol consumption, Biology, entymology, Genetics, hornets, insects, Science / /

Many animals, including humans, have developed a taste for alcohol in some form, but excessive consumption often leads to adverse health effects. One exception is the Oriental wasp. According to a new paper published in the Proceedings of the National Academy of Sciences, these wasps can guzzle seemingly unlimited amounts of ethanol regularly and at very high concentrations with no ill effects—not even intoxication. They pretty much drank honeybees used in the same experiments under the table.

“To the best of our knowledge, Oriental hornets are the only animal in nature adapted to consuming alcohol as a metabolic fuel,” said co-author Eran Levin of Tel Aviv University. “They show no signs of intoxication or illness, even after chronically consuming huge amounts of alcohol, and they eliminate it from their bodies very quickly.”

Per Levin et al., there’s a “drunken monkey” theory that predicts that certain animals well-adapted to low concentrations of ethanol in their diets nonetheless have adverse reactions at higher concentrations. Studies have shown that tree shrews, for example, can handle concentrations of up to 3.8 percent, but in laboratory conditions, when they consumed ethanol in concentrations of 10 percent or higher, they were prone to liver damage.

Similarly, fruit flies are fine with concentrations up to 4 percent but have increased mortality rates above that range. They’re certainly capable of drinking more: fruit flies can imbibe half their body volume in 15 percent (30 proof) alcohol each day. Not even spiking the ethanol with bitter quinine slows them down. Granted, they have ultra-fast metabolisms—the better to burn off the booze—but they can still become falling-down drunk. And fruit flies vary in their tolerance for alcohol depending on their genetic makeup—that is, how quickly their bodies adapt to the ethanol, requiring them to inhale more and more of it to achieve the same physical effects, much like humans.

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a-candy-engineer-explains-the-science-behind-the-snickers-bar

A candy engineer explains the science behind the Snickers bar

Biology, candy, Food science, health, Science, syndication / /

It’s Halloween. You’ve just finished trick-or-treating and it’s time to assess the haul. You likely have a favorite, whether it’s chocolate bars, peanut butter cups, those gummy clusters with Nerds on them, or something else.

For some people, including me, one piece stands out—the Snickers bar, especially if it’s full-size. The combination of nougat, caramel, and peanuts coated in milk chocolate makes Snickers a popular candy treat.

As a food engineer studying candy and ice cream at the University of Wisconsin-Madison, I now look at candy in a whole different way than I did as a kid. Back then, it was all about shoveling it in as fast as I could.

Now, as a scientist who has made a career studying and writing books about confections, I have a very different take on candy. I have no trouble sacrificing a piece for the microscope or the texture analyzer to better understand how all the components add up. I don’t work for, own stock in, or receive funding from Mars Wrigley, the company that makes Snickers bars. But in my work, I do study the different components that make up lots of popular candy bars. Snickers has many of the most common elements you’ll find in your Halloween candy.

Let’s look at the elements of a Snickers bar as an example of candy science. As with almost everything, once you get into it, each component is more complex than you might think.

Snickers bars contain a layer of nougat, a layer of caramel mixed with peanuts, and a chocolate coating.

Credit: istarif/iStock via Getty Images

Snickers bars contain a layer of nougat, a layer of caramel mixed with peanuts, and a chocolate coating. Credit: istarif/iStock via Getty Images

Airy nougat

Let’s start with the nougat. The nougat in a Snickers bar is a slightly aerated candy with small sugar crystals distributed throughout.

One of the ingredients in the nougat is egg white, a protein that helps stabilize the air bubbles that provide a light texture. Often, nougats like this are made by whipping sugar and egg whites together. The egg whites coat the air bubbles created during whipping, which gives the nougat its aerated texture.

A boiled sugar syrup is then slowly mixed into the egg white sugar mixture, after which a melted fat is added. Since fat can cause air bubbles to collapse, this step has to be done last and very carefully.

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how-can-you-write-data-to-dna-without-changing-the-base-sequence?

How can you write data to DNA without changing the base sequence?

biochemistry, Biology, DNA storage, epigenetics, Science, Storage / /

The developers of the system call each of these potentially modifiable spots on the template an epi-bit, with the modified version corresponding to a 1 in a conventional computer bit and the unmodified version corresponding to a 0. Because no synthesis is required, multiple bits can be written simultaneously. To read the information, the scientists rigged the system so that 1s fluoresce and 0s don’t. The fluorescence, along with the sequences of bases, was read as the DNA was passed through a tiny pore.

Pictures in a meta-genome

Using this system, Zhang et al. created five DNA templates and 175 bricks to record 350 bits at a time. Using a collection of tagged template molecules, the researchers could store and read roughly 275,000 bits, including a color picture of a panda’s face and a rubbing of a tiger from the Han dynasty, which ruled China from 202 BCE to 220 CE.

They then had 60 student volunteers “with diverse academic backgrounds” store texts of their choice in epi-bits using a simple kit in a classroom. Twelve of the 15 stored texts were read successfully.

We’re not quite ready for your cat videos yet, though. There are still errors in the printing and reading steps, and since these modifications don’t survive when DNA is copied, making additional versions of the stored information may get complicated. Plus, the stability of these modifications under different storage conditions remains unknown, although the authors note that their epi-bits stayed stable at temperatures of up to 95o° C.

But once these and a few other problems are solved—and the technology is scaled up, further optimized and automated, and/or tweaked to accommodate other types of epigenetic modifications—it will be a clever and novel way to harness natural data storage methods for our needs.

Nature, 2024.  DOI: 10.1038/s41586-024-08040-5

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bizarre-fish-has-sensory-“legs”-it-uses-for-walking-and-tasting

Bizarre fish has sensory “legs” it uses for walking and tasting

Biology, evolutionary biology, fish, neurobiology, Science, sensory neurons / /

Finding out what controls the formation of sensory legs meant growing sea robins from eggs. The research team observed that the legs of sea robins develop from the three pectoral fin rays that are around the stomach area of the fish, then separate from the fin as they continue to develop. Among the most active genes in the developing legs is the transcription factor (a protein that binds to DNA and turns genes on and off) known as tbx3a. When genetically engineered sea robins had tbx3a edited out with CRISPR-Cas9, it resulted in fewer legs, deformed legs, or both.

“Disruption of tbx3a results in upregulation of pectoral fin markers prior to leg separation, indicating that leg rays become more similar to fins in the absence of tbx3a,” the researchers said in a second study, also published in Current Biology.

To see whether genes for sensory legs are a dominant feature, the research team also tried creating sea robin hybrids, crossing species with and without sensory legs. This resulted in offspring with legs that had sensory capabilities, indicating that it’s a genetically dominant trait.

Exactly why sea robins evolved the way they did is still unknown, but the research team came up with a hypothesis. They think the legs of sea robin ancestors were originally intended for locomotion, but they gradually started gaining some sensory utility, allowing the animal to search the visible surface of the seafloor for food. Those fish that needed to search deeper for food developed sensory legs that allowed them to taste and dig for hidden prey.

“Future work will leverage the remarkable biodiversity of sea robins to understand the genetic basis of novel trait formation and diversification in vertebrates,” the team also said in the first study. “Our work represents a basis for understanding how novel traits evolve.”

Current Biology, 2024. DOI:  10.1016/j.cub.2024.08.014, 10.1016/j.cub.2024.08.042

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dna-confirms-these-19th-century-lions-ate-humans

DNA confirms these 19th century lions ate humans

animal behavior, animals, Biology, DNA analysis, forensic archaeology, lions, Security / /

For several months in 1898, a pair of male lions turned the Tsavo region of Kenya into their own human hunting grounds, killing many construction workers who were building the Kenya-Uganda railway.  A team of scientists has now identified exactly what kinds of prey the so-called “Tsavo Man-Eaters” fed upon, based on DNA analysis of hairs collected from the lions’ teeth, according to a recent paper published in the journal Current Biology. They found evidence of various species the lions had consumed, including humans.

The British began construction of a railway bridge over the Tsavo River in March 1898, with Lieutenant-Colonel John Henry Patterson leading the project. But mere days after Patterson arrived on site, workers started disappearing or being killed. The culprits: two maneless male lions, so emboldened that they often dragged workers from their tents at night to eat them. At their peak, they were killing workers almost daily—including an attack on the district officer, who narrowly escaped with claw lacerations on his back. (His assistant, however, was killed.)

Patterson finally managed to shoot and kill one of the lions on December 9 and the second 20 days later. The lion pelts decorated Patterson’s home as rugs for 25 years before being sold to Chicago’s Field Museum of Natural History in 1924. The skins were restored and used to reconstruct the lions, which are now on permanent display at the museum, along with their skulls.

Tale of the teeth

The Tsavo Man-Eaters naturally fascinated scientists, although the exact number of people they killed and/or consumed remains a matter of debate. Estimates run anywhere from 28–31 victims to 100 or more, with a 2009 study that analyzed isotopic signatures of the lions’ bone collagen and hair keratin favoring the lower range.

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octopus-suckers-inspire-new-tech-for-gripping-objects-underwater

Octopus suckers inspire new tech for gripping objects underwater

adhesives, Biology, biomimicry, cephalopods, materials science, octopuses, Science / /

Over the last few years, Virginia Tech scientists have been looking to the octopus for inspiration to design technologies that can better grip a wide variety of objects in underwater environments. Their latest breakthrough is a special switchable adhesive modeled after the shape of the animal’s suckers, according to a new paper published in the journal Advanced Science.

“I am fascinated with how an octopus in one moment can hold something strongly, then release it instantly. It does this underwater, on objects that are rough, curved, and irregular—that is quite a feat,” said co-author and research group leader Michael Bartlett. “We’re now closer than ever to replicating the incredible ability of an octopus to grip and manipulate objects with precision, opening up new possibilities for exploration and manipulation of wet or underwater environments.”

As previously reported, there are several examples in nature of efficient ways to latch onto objects in underwater environments, per the authors. Mussels, for instance, secrete adhesive proteins to attach themselves to wet surfaces, while frogs have uniquely structured toe pads that create capillary and hydrodynamic forces for adhesion. But cephalopods like the octopus have an added advantage: The adhesion supplied by their grippers can be quickly and easily reversed, so the creatures can adapt to changing conditions, attaching to wet and dry surfaces.

From a mechanical engineering standpoint, the octopus has an active, pressure-driven system for adhesion. The sucker’s wide outer rim creates a seal with the object via a pressure differential between the chamber and the surrounding medium. Then muscles (serving as actuators) contract and relax the cupped area behind the rim to add or release pressure as needed.

There have been several attempts to mimic cephalopods when designing soft robotic grippers, for example. Back in 2022, Bartlett and his colleagues wanted to go one step further and recreate not just the switchable adhesion but also the integrated sensing and control. The result was Octa-Glove, a wearable system for gripping underwater objects that mimicked the arm of an octopus.

Improving the Octa-Glove

Grabbing and releasing underwater objects of different sizes and shapes with an octopus-inspired adhesive. Credit: Chanhong Lee and Michael Bartlett

For the adhesion, they designed silicone stalks capped with a pneumatically controlled membrane, mimicking the structure of octopus suckers. These adhesive elements were then integrated with an array of LIDAR optical proximity sensors and a micro-control for the real-time detection of objects. When the sensors detect an object, the adhesion turns on, mimicking the octopus’s nervous and muscular systems. The team used a neoprene wetsuit glove as a base for the wearable glove, incorporating the adhesive elements and sensors in each finger, with flexible pneumatic tubes inserted at the base of the adhesive elements.

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medicine-nobel-goes-to-previously-unknown-way-of-controlling-genes

Medicine Nobel goes to previously unknown way of controlling genes

Biology, evolution, gene regulation, microRNA, Nobel prize, Science / /

Based on the stereotypical hairpin structure, researchers have scanned genomes and found over 38,000 likely precursors; nearly 50,000 mature microRNAs have been discovered by sequencing all the RNA found in cells from a variety of species. While found widely in animals, they’ve also been discovered in plants, raising the possibility that they existed in a single-celled ancestral organism.

While some microRNA genes, including lin-4 and let-7, have dramatic phenotypes when mutated, many have weak or confusing effects. This is likely in part due to the fact that a single microRNA can bind to and regulate a variety of genes and so may have a mix of effects when mutated. In other cases, several different microRNAs may bind to the same messenger RNA, creating a redundancy that makes the loss of a single microRNA difficult to detect.

Nevertheless, there’s plenty of evidence that, collectively, they’re essential for normal development in many organisms and tissues. Knocking out the gene that encodes the Dicer protein, which is needed for forming mature microRNAs, causes early embryonic lethality. Knockouts of the gene in specific cell types cause a variety of defects. For example, B cells never mature if Dicer is lost in that cell lineage, and a knockout in nerve cells causes microcephaly and limiting branching of connections among neurons, leading the animals to die shortly after birth.

This being the Medicine prize, the Nobel Committee also cite a number of human genetic diseases that are caused by mutations in microRNA genes.

Overall, the award highlights just how complex life is at the cellular level. There’s a fair number of genes that have to be made by every cell simply to enable their survival. But as for the rest, they exist embedded in complex regulatory networks that interact to ensure that proteins are made only where and when they’re needed, and often degraded if they somehow get made anyway. And every now and then, fundamental research in an oddball species is still telling us unexpected things about those networks.

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strange-“biotwang”-id’d-as-bryde’s-whale-call

Strange “biotwang” ID’d as Bryde’s whale call

animal behavior, baleen whales, bioacoustics, Biology, Science, whale communication, whales / /

In 2014, researchers monitoring acoustic recordings from the Mariana Archipelago picked up an unusual whale vocalization with both low- and high-frequency components. It seemed to be a whale call, but it sounded more mechanical than biological and has since been dubbed a “biotwang.”

Now a separate team of scientists has developed a machine-learning model to scan a dataset of recordings of whale vocalizations from various species to help identify the source of such calls. Combining that analysis with visual observations allowed the team to identify the source of the biotwang: a species of baleen whales called Bryde’s (pronounced “broodus”) whales. This should help researchers track populations of these whales as they migrate to different parts of the world, according to a recent paper published in the journal Frontiers in Marine Science.

Marine biologists often rely on a powerful tool called passive acoustic monitoring for long-term data collection of the ocean’s acoustic environment, including whale vocalizations. Bryde’s whale calls tend to be regionally specific, per the authors. For instance, calls in the eastern North Pacific are pretty well documented, with frequencies typically falling below 100 Hz, augmented by harmonic frequencies as high as 400 Hz. Far less is known about the sounds made by Bryde’s whales in the western and central North Pacific, since for many years there were only three known recordings of those vocalizations—including a call dubbed “Be8” (starting at 45 Hz with multiple harmonics) and mother-calf calls.

That changed with the detection of the biotwang in 2014. It’s quite a distinctive, complex call that typically lasts about 3.5 seconds, with five stages, starting at around 30 Hz and ending with a metallic sound that can reach as high as 8,000 Hz. “It’s a real weird call,” co-author Ann Allen, a scientist at NOAA Fisheries, told Ars. “Anybody who wasn’t familiar with whales would think it was some sort of artificial sound, made by a naval ship.” The 2014 team was familiar with whale vocalizations and originally attributed the strange sound to baleen whales. But that particular survey was autonomous, and without accompanying visual observations, the scientists could not definitively confirm their hypothesis.

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ants-learned-to-farm-fungi-during-a-mass-extinction

Ants learned to farm fungi during a mass extinction

agriculture, ants, Biology, evolution, fungi, Science / /

Timing is everything

Tracing the lineages of agricultural ants to their most recent common ancestor revealed that the ancestor probably lived through the end-Cretaceous mass extinction—the one that killed off the dinosaurs. The researchers argue that the two were almost certainly related. Current models suggest that there was so much dust in the atmosphere after the impact that set off the mass extinction that photosynthesis shut down for nearly two years, meaning minimal plant life. By contrast, the huge amount of dead material would allow fungi to flourish. So, it’s not surprising that ants started to adapt to use what was available to them.

That explains the huge cluster of species that cooperate with fungi. However, most of the species that engage in organized farming don’t appear until roughly 35 million years after the mass extinction, at the end of the Eocene (that’s about 33 million years before the present period). The researchers suggest that the climate changes that accompanied the transition to the Oligocene included a drying out of the tropical Americas, where the fungus-farming ants had evolved. This would cut down on the availability of fungi in the wild, potentially selecting for the ability of species that could propagate fungal species on their own.

This also corresponds to the origins of the yeast strains used by farming ants, as well as the most specialized agricultural fungal species. But it doesn’t account for the origin of coral fungus farmers, which seems to have occurred roughly 10 million years later.

The work gives us a much clearer picture of the origin of agriculture in ants and some reasonable hypotheses regarding the selective pressures that might have led to its evolution. In the long term, however, the biggest advance here may be the resources generated during this study. Ultimately, we’d like to understand the genetic basis for the changes in the ants’ behavior, as well as how the fungi have adapted to better provide for their farmers. To do that, we’ll need to compare the genomes of agricultural species with their free-living relatives. The DNA gathered for this study will ultimately be needed to pursue those questions.

Science, 2024. DOI: 10.1126/science.adn7179  (About DOIs).

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