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Big birds can innovate for food

Some birds are widely recognized as intelligent – crows and parrots for example. The bigger ones, including ostriches, emus and rheas, are thought to be less intelligent due to their small relative brain size.

But a new study suggests these birds can learn through exploration and trial-and-error. The study, published in Scientific Reports, provides the first evidence of technical innovation in palaeognath birds, hinting that problem-solving abilities may have evolved earlier in birds than previously thought.

Researchers tested whether these birds could solve a foraging problem using a rotary puzzle – a wheel that had to be turned to access food. While emus and one rhea successfully figured out the task, ostriches did not.

One rhea even discovered an alternative solution by removing a bolt to reach the food. The findings open new avenues for studying bird cognition and how different species develop innovative behaviors.

More: Covid was no barrier for UAE bird enthusiasts

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Your pupils change as you breathe

The size of your pupil systematically fluctuates with your breathing, according to a new study from Karolinksa Institutet. The pupillary respiratory-phase response (PRP response) means pupils are smallest at the start of each inhale and largest during exhale.

Traditionally, pupil size has been linked to light exposure, fixating on objects and emotional or cognitive states. This study, published in the Journal of Physiology, tested various breathing conditions, lighting environments and even participants without a sense of smell.

The consistency of their findings suggests that brainstem circuits drive this PRP response, independent of external influences.

Beyond deepening our understanding of vision and neural activity, these findings could have implications for human-computer interaction and clinical research, where pupil dynamics are often used as markers of brain function.

More: Through their eyes

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SHIELDS UP

Beyond applying sunscreen before a day at the beach, we generally don’t think much about our exposure to radiation. We have Earth’s magnetic field to thank for that, but for astronauts who go beyond the planet’s protective layer, sunscreen won’t quite cut it.

A fungus found growing in the aftermath of Chernobyl, however, might.

Cladosporium spaerospermum is one such radiation-loving fungal species, found on Earth in extreme places, like the remains of the Chernobyl Nuclear Power Plant in Ukraine. While most plants use energy from the sun for photosynthesis, this type of fungus draws its energy from radiation in a process called radiosynthesis.

Researchers believe large amounts of melanin in the cell walls of these fungi protect the cells from radiation damage, with melanin now being explored as biotechnological means of radiation shielding.

For applications in space, researchers offer different approaches:

Ekaterina Dadachova, professor of pharmacy at the University of Saskatchewan, Canada, wants astronauts to eat more mushrooms; Nils Averesch, research engineer at Stanford, would rather grow a thick layer of fungus on spacecraft and future Martian or lunar habitats. Averesch isn’t joking — to bring radiation exposure down to Earth-like levels, a habitat on Mars would need an estimated “2.3m layer of melanized fungal biomass.”

Remember: These radiotrophic fungi are already in space. A survey of the environmental contamination on board the International Space Station (ISS) revealed many fungal species on surfaces and in the air, including Aspergillus, Penicillium and Saccharomyces species. Although the ISS still enjoys some shielding from the Earth’s magnetosphere, it receives elevated levels of radiation compared with Earth, and astronauts can stay in orbit for up to only a year.

Eat them

“Life emerged on Earth at a time when there was much higher background radiation, and early life forms must have considerable radiation resistance,” Dadachova says in her article for Current Opinion in Microbiology. “Although current background radiation levels are much lower than in the early days on Earth, earthly life still exists in a field of radiation.”

Dadachova highlights the “Evolution Canyon” site in Israel, where the two slopes of the canyon, separated by just 200 meters of open grassland, represent drastically different biomes. The south-facing slope receives 200-800 percent more solar radiation than the north-facing slope, which is temperate and shady.

The south-facing slope is populated by many species of melanized fungi, such as Aspergillus niger, which contains “three times more melanin than the same species from the north-facing slope.”

Melanin pigments are found in all biological kingdoms, suggesting these compounds are ancient molecules that emerged early in the course of evolution.

Dadachova’s research examines the radioprotective effects of melanized fungi in patients undergoing radiation therapy for cancer treatment and believes there could be potential for protecting people in prolonged space flight.

CAPTION: Cladosporium spaerosporium IMAGE: Shutterstock

Speaking about mice fed black mushrooms being protected from high doses of external radiation, Dadachova says: “It’s not like you can eat a mushroom and be protected forever, but if you experience a radiation influx while the mushroom’s melanin is in your digestive tract, it protects it from really high doses of radiation.”

“Very recently, we obtained soluble fungal melanin which can be given after exposure to radiation to mitigate radiation damage,” Dadachova tells KUST Review.

Dadachova’s team fed soluble allomelanin to mice that had been exposed to high doses of gamma radiation. They found the effects of the radiation were mitigated when allomelanin was administered within 24 hours of irradiation.

“Based on these findings, soluble allomelanin derived from a fungal source could serve as an easily sourced, cost-effective and viable countermeasure to accidental radiation exposure,” Dadachova says. “This is an important step forward in this melanin and radiation investigation.”

Grow them

Stanford’s Averesch was part of the research team investigating just how well Cladosporium spaerospermum can grow in space. Petri dishes loaded with the fungus were sent to the ISS and oriented so they faced away from Earth. To compare, a number of petri dishes with the same fungus remained earthside.

The team found the fungi onboard the ISS had a microbial growth advantage, which could be associated with increased radiation in space. The melanized fungal biomass may have radioprotective properties and could even be used as an energy-storage device on spacecraft.

“Solutions to radiation exposure on interplanetary travel are more restricted by up-mass limitations than any other factor of space travel,” Averesch says. “Being living organisms, micro-fungi self-replicate from microscopic amounts, which could allow significant weight savings. Biotechnology would thus prove to be an invaluable asset to life support and resource management for explorers on future missions to the moon, Mars and beyond.”

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A marriage steeped in deception

While many species use elaborate displays to attract mates — peacocks flaunt their feathers, deer grow imposing antlers — female dance flies (Empididae) take a slightly different approach. Though they puff up their bodies, darken their wings and sprout extra hair to appear more fertile than they really are, it’s all an illusion

And the males might be evolving sharper vision to see through the deception.

The aptly named dance fly is known for its intricate courtship rituals. To the naked eye, a swarm of these tiny insects may seem like a chaotic buzz of movement, but their aerial displays follow a structured pattern. Females perform elaborate maneuvers to attract a mate while males closely observe their traits to assess reproductive fitness.

Males are particularly drawn to females with thick, hairy legs and swollen bellies —suggesting an abundance of eggs and better chances of carrying on the genes. But the females are masters of trickery, using clever tactics to exaggerate their appearance.

“They swallow air to inflate their abdomen and look larger when they swarm,” explains Axel Wiberg, researcher at Stockholm University and lead author on a 2024 study on the correlation of evolving physical traits of the male and female dance flies. “They’ve also developed hair on their legs and larger, darker wings to enhance the illusion.”

Beyond visual deception, courtship involves another key element: gifting. Males capture prey, wrap it in a silken cocoon and present it to the chosen female.

For the most part, this could be the only food she will eat in her lifetime as females can’t feed themselves.

CAPTION: Axel Wiberg IMAGE: Elina Immonen

This mating ritual happens with several males, and once the female has eaten enough high protein “gifts,” she can lay eggs.

It does seem, however, the gaming goes both ways.

Some males eat part of the gift before wrapping it or simply give a ball of silk with no gift inside at all. Show up empty-handed, however, and suffer rejection.
But while there’s trickery happening from both genders, the females’ ruse may be losing its effectiveness.

Researchers at the University of Gothenburg and Stockholm University have found that male dance flies are evolving better eyesight — allowing them to detect which females are truly the most fertile and which are simply putting on a show hoping for a snack.

In certain dance fly species, there is a correlation of females with big bellies and thick, hairy legs to larger eye facets on the males. This indicates the males have evolved over time to suss out the most fertile females.

She [the female] may develop entirely new strategies to gain an evolutionary advantage.

– Axel Wiberg, Stockholm University

“For generations, male flies with the largest facets have been favored in mating, and their genes are passed on. We see this as an evolutionary system where the development of different traits in male and female flies has been alternating,” says Luc Bussière, evolutionary biologist at the University of Gothenburg and co-author on the study.

CAPTION: Luc Bussière IMAGE: Olof Lönnehed

How can this dance continue to evolve the species?

Gothenburg University’s publication of the findings says that the females likely developed characteristics over time as the males became better at detecting the ruse.
So, what happens next as each gender continues to evolve to beat out the other?

“Perhaps the female develops new traits that make it harder for the male to judge her size. Or she may develop entirely new strategies to gain an evolutionary advantage. For example, we see that in the species with the largest facets in the male, the female also has slightly enlarged facets, but on the underside of the eye.

We don’t know what this means, but perhaps it helps the female to see an approaching male more quickly and thus find an advantageous position in the swarm,” Wiberg tells KUST Review.

The paper was published in the International Journal of Organic Evolution.