Science in brief: From record-breaking whales to aromatherapy for bees

And other stories from around the world

Cuvier's beaked whales (Danielle Waples/Duke University via NYT)

Beaked whale shatters record with 3 hour, 42 minute dive

The 1959 movie Ben-Hur runs some three-and-a-half hours. A Cuvier’s beaked whale could watch the entire film underwater, never taking a gulp of air, with time to spare.

“They are remarkable divers,” says Nicola Quick, a marine biologist at Duke University. These pointy-snouted cetaceans, which frequent the world’s deep waters, have clocked the longest and deepest dives of any marine mammal ever recorded, plunging nearly 10,000 feet below the surface of the sea.

Quick’s latest paper, published 23 Sept in the Journal of Experimental Biology, documents the whales’ most impressive observed descent to date: 3 hours, 42 minutes, trouncing the previous record by over an hour.

The new record is nearly seven times longer than scientists expect the mysterious mammals should be able to dive, based on scientific understanding of their body size and metabolic rate.

“This is just so beyond what we’ve seen before,” said Andreas Fahlman, a physiologist at the Oceanographic Foundation of the Valencian Community in Spain and an author on the study. “They’re not supposed to be able to do this, but they do.”

Most people, on the other hand, can’t hold their breath for more than a couple of minutes, although Guinness World Records documented one free diver who went more than 24 minutes without coming up for air.

The biology-bending stunts of beaked whales come with serious perks. By swooping down into light-starved layers of the ocean, the animals can find and feast on droves of fish and squid that are not accessible to most other predators.

But this predilection for the deep also places beaked whales among the least well understood mammals in the world, Quick said.

Quick and her colleagues tagged two dozen Cuvier’s beaked whales near Cape Hatteras in North Carolina. Between 2014 and 2018, the team tracked the whales’ movements as the animals undertook 3,680 foraging dives.

Previous calculations have estimated that Cuvier’s beaked whales, which can grow as large as 5,000 pounds and 20 feet long, should be able to store enough oxygen to sustain dives of 33 minutes. 

But most of the dives executed by the whales in Quick’s study lasted about an hour, with a small handful stretching past the two-hour mark.

Remarkably, the whales seemed unfazed by these feats: There was almost no relationship between the duration of their dives and the amount of time they spent recovering at the water’s surface.

— Katherine J. Wu

Why so blue, tarantula? A mystery gets a new clue

Tarantulas are fuzzy, active in the dark and troublingly large – with some South American species tip-tapping around on leg spans bigger than the hands of professional basketball players. Many of them are also beautiful.

Alongside those drab brown tarantulas, many other species in the family sport violets, purples, reds, greens or even silky, metallic blues. But those same fierce hues also posed an evolutionary puzzle.

Scientists thought tarantulas were colourblind. Plus they’re active only around twilight or nighttime, when colours are muted. So why be pretty at all?

“Something so obvious as their very bright and vivid colours remains incredibly mysterious,” says Saoirse Foley, a biologist at Carnegie Mellon University who got her first pet tarantula at age 11. “We had no idea why.”

Now we might. As Foley started studying the question during graduate school at the National University of Singapore, her team found that the green colours of some species might help with camouflage. 

But the metallic blues of other tarantulas don’t seem to help with defence, hinting that they might be for attracting mates — and even that tarantulas might see a much more vibrant world than we knew, her team reported 23 Sept in Proceedings of the Royal Society B.

“I’m thrilled,” says Nathan Morehouse, an expert on spider vision at the University of Cincinnati who was not involved in the analysis. “This makes tarantulas a very exciting group moving forward to think about.”

The team turned to an online database – birdspiders.com – for undoctored photos they could use to measure bright greens, blues and other colours from across the tarantula family tree.

They found that green hues had evolved several times in spider lineages that had previously taken to the trees, suggesting such colours help tarantulas hide among leaves in faint light.

But some tarantulas don’t just hide from predators. Some warn off their pursuers with defensive tricks, such as rubbing their mouthparts to create a hissing sound.

That led the team to wonder if blueness might be a form of warning to predators – don’t mess with me – akin to these behaviours. But the team saw that blueness seemed unrelated to whether a tarantula was capable of fighting back.

Instead it looked like a much older trait, an ancestral quality retained by many tarantula lineages. That suggests, they say, that the colour might be intended for other tarantulas, not just predators.

— Joshua Sokol

Infected by a virus, a killer fungus turns into a friend

When crops have nightmares, they dream of Sclerotinia sclerotiorum. The fungus, known by stomach-turning names such as “white mold” and “watery soft rot”, manifests as a cottony, cream-coloured fuzz that attaches to stems, where it gouges wound-like lesions. Within days, the plant is dead.

“It really is a deadly fungus,” says Daohong Jiang, an agricultural microbiologist at Huazhong Agricultural University in Hubei, China.

Some 400 species of plants are thought to be susceptible to the pathogen, including soybeans, which fell in droves to the fungus in 2009, costing farmers $560m. The fungus also goes dormant in soil for years, seeding new infections that can raze entire fields of crops.

Jiang has spent 10 years hot on Sclerotinia’s trail in the hopes of bringing the blight to heel. He and his colleagues now think they’ve found an answer: a treatment that doesn’t just stop the fungus from killing but transforms it into a probiotic that can boost plant growth and enhance resilience to future disease. They reported their findings 29 Sept in the journal Molecular Plant.

Their horticultural hero is a virus called SsHADV-1. Typically, it rides around on a fungus-munching insect called a mushroom fly. And it’s able to fully domesticate Sclerotinia over the course of a single encounter, turning a wolf into a watchdog.

“There have been some reports about how viruses are able to manipulate hosts, but this one is so unique,” says Aurelie Rakotondrafara, a plant pathologist at the University of Wisconsin, Madison, who was not involved in the study. “You can’t help but ask: How is this possible?”

Jiang’s team first noticed the virus’s unusual sway over Sclerotinia over a decade ago when they discovered that rapeseed plants were able to coexist with virus-infected strains of the fungus, despite being felled in droves by their virus-free counterparts.

Their latest work showed that the virus hijacked its host’s cells on a global scale, controlling which genes the fungus shut on and off as it infiltrated rapeseed plants.

Virus-infected fungi, for instance, no longer flooded plants with tissue-macerating juices. And while they still forced their way into a host’s cells, the virus-infected fungi were far more gracious tenants and left the rapeseed mostly intact.

The virus had, in effect, compelled the fungus into sheathing its plant-impairing weapons, Rakotondrafara says: “A mean pathogen turned into a gentle microbe.”

— Katherine J. Wu

First fossil feather ever found belonged to this dinosaur

The feather looks like any feather you might find on the ground. But it’s not. It’s about 150 million years old, and it fluttered to the ground back when the dinosaurs roamed what is today called Bavaria. 

It’s entombed in limestone, and, when paleontologists unearthed it in 1861, it became the first fossil feather ever discovered.

Many paleontologists think the feather came from archaeopteryx lithographica, a creature that, with its feathered wings and sharp-toothed mouth, bears features of both dinosaurs and birds, making it a herald of the evolutionary transition between the two groups.

But that first-known fossil feather isn’t attached to an archaeopteryx skeleton, and so for more than a century, not all scientists have agreed on the identity of the feather’s owner.

“There’s been this debate, even when the feather was found: Does this isolated feather belong to the same animal as these skeletal specimens of archaeopteryx?” says Ryan Carney, a paleontologist and epidemiologist at the University of South Florida.

In a study published 30 Sept in the journal Scientific Reports, Carney and a team of colleagues compared the feather with the fossil remains of other feathers found with archaeopteryx fossils more recently, and they claim that the debate is now settled: The feather belongs to archaeopteryxIn 2019 scientists argued in a paper that the feather might have belonged to another winged dinosaur species. 

Many scientists have been critical of this hypothesis, and Carney and his team set out to counter it by studying the shape of the feather. 

They hoped to see whether it matched the anatomy of feathers that were still connected to other fossilised archaeopteryx specimens. They report that the feathers, for instance, have similar widths, lengths and curvatures.

Using a high-powered scanning electron microscope, the team also captured images of the feather with enough detail to reveal the presence of thousands of molecules called melanosomes – organelles responsible for the feather’s colouration – that preserve the feather’s original pigments. The pigments suggest that the feather was matte black in colour.

Whether this paper settles the argument, Stephen Brusatte, a vertebrate paleontologist at the University of Edinburgh, says studying the feather continues to offer useful insights.

“To me, ultimately, the important thing is that this feather belonged to a small-winged Jurassic animal that could fly pretty well, regardless of whether it was shed from the wing of archaeopteryx or another bird,” he says.

— Lucas Joel

Aromatherapy in the apiary is what bees need

To fill your homes with blueberries, sunflowers and almonds, farmers rent honeybees. When all goes well, the bees pollinate the flowers, resulting in ample yields. But sometimes the rental bees buzz off and pollinate wildflowers instead.

Walter Farina, a biologist at the University of Buenos Aires, and his colleagues have figured out a solution to this problem involving scent, which they reported 17 Sept in the journal Current Biology.

Farina knew from previous work that hives remember the scents of food collected in the past. Most importantly, he knew that these memories could bias where bees forage.

“This led us to wonder if we could guide bees to specific crops by inserting an odor of that crop into a hive and giving them a memory of food they never had,” Farina says.

Over the course of six years, Farina and his colleagues placed scented sugar water into hives that had been placed next to Argentine sunflower farms. 

In some cases, the hives were given water laced with sunflower fragrance. As a control, some hives were given water laced with jasmine. 

To keep track of which bees were being exposed to the different solutions, the researchers put coloured powders at the entrance to the hives such that bees exposed to sunflower scent were stained blue and those exposed to jasmine were pink.

Farina and his colleagues placed pollen traps inside the hives that collected pollen grains off bees returning from foraging activities that were later brought to the lab for identification.

The researchers also went out into the sunflower fields, captured bees foraging there and took note of whether they were pink or blue.

The results could not have been clearer, with a variety of measurements suggesting that the sunflower scent had increased crop pollination. 

When the farmers reported their yields, this was confirmed: Fields adjacent to hives given the sunflower solution produced between 37 per cent and 61 per cent more sunflower seeds than did fields next to the jasmine hives.

“This is real work being done in real fields rather than just the lab,” says Martin Giurfa, who studies bee behavior at CNRS Toulouse in France. “These are incredibly encouraging findings.”

“Our scent technique might help better focus the rental bees on crops and relieve pressure on native pollinators,” Farina says. Giurfa agrees this is possible but adds, “We need field studies on these other pollinators to know for sure.” 

— Matt Kaplan

© The New York Times