A Round Up of Latest Research News on The Lighthouse

A major new study has uncovered the genetic basis for bill colouration in Australian long-tailed finches, revealing how yellow and red bill colours evolved through changes in just a few key genes.

A couple of birds standing next to each other

Image sourced from: https://lighthouse.mq.edu.au/article/november-2024/new-genetic-discovery-reveals-how-birds-get-their-coloured-bills

The research, published in Current Biology, was led by Professor Simon Griffith at Macquarie University and Dr Daniel Hooper from the American Museum of Natural History.

"Modern genomic techniques provide incredible insight into how relatively subtle genetic changes can lead to profound changes in animal colour," says Professor Griffith, an evolutionary biologist from Macquarie's School of Natural Sciences.

The study focused on two subspecies of the long-tailed finch found across northern Australia – one with a yellow bill from the Kimberley region, and another with a red bill from the Northern Territory. Where these subspecies meet, they produce offspring with orange bills.

Most long-tailed finches have bright red bills, with the colour derived from carotenoid pigments in the seeds they eat. The birds produce enzymes that convert these yellow pigments into red ones, which are deposited in their bills.

By analysing the DNA of over 900 finches, researchers identified the exact genetic variations responsible for the different bill colours.

Yellow-billed finches have genetic variations preventing them from converting yellow dietary pigments into red ones in their bills.

Although yellow-billed finches don't produce red carotenoids in their bills, they still make them in their retinas, suggesting that the birds control the genes for making red colouring differently in different parts of their bodies.

The research revealed that yellow bill colouration, which appeared around 100,000 years ago, provided some evolutionary advantage, allowing these genes to spread into populations of red-billed finches.

Lights trick vision of Great White sharks, could protect surfers, by Tim Dodd.

Macquarie researchers discover strategic lighting can create an "invisibility cloak" effect that deters Great White shark attacks.

Research published in Current Biology reveals that lights can prevent Great White sharks from attacking by disrupting the silhouettes they use to identify prey.

Macquarie University's Dr Laura Ryan and Professor Nathan Hart found that Great Whites, despite being colour blind with poor visual acuity, rely heavily on detecting silhouettes when hunting—explaining why they sometimes mistake surfers for seals.

Testing in South Africa's Mossel Bay, the researchers towed seal-shaped decoys through shark-infested waters. Adding LED lights in specific patterns significantly reduced attacks.

"It's like an invisibility cloak, splitting the visual silhouette into smaller bits," explains Professor Hart.

The most effective design featured light stripes placed perpendicular to the direction of movement, breaking up the seal-like outline and making it unrecognisable to sharks. Longitudinal stripes proved less effective as they still resembled prey.

The team is now developing surfboard prototypes with embedded LEDs and testing the system's effectiveness when surfboards are stationary. They're also investigating whether the approach works with bull and tiger sharks.

While results are promising, the researchers caution that further testing is needed before the technology should be widely deployed for human protection.

Fatal Attraction: Engineered Male Mosquitoes Could Transform Disease Control, by Fran Molloy.

A couple of mosquitoes standing on top of each other

Image from https://www.mq.edu.au/faculty-of-science-and-engineering/news/news/toxic-male-technique

Macquarie University researchers have developed a revolutionary pest control method that turns male insects into allies against disease by engineering them to reduce female lifespan after mating.

Scientists at Macquarie University have created an innovative approach to controlling disease-carrying insects that works faster than any previous genetic technique.

The "Toxic Male Technique" (TMT) involves genetically engineering male insects to produce insecticidal proteins in their reproductive system that significantly reduce female lifespans after mating.

"By targeting female mosquitoes themselves rather than their offspring, TMT could work as quickly as pesticides without harming beneficial species," says lead author Sam Beach, a PhD candidate from Applied BioSciences at Macquarie University.

In laboratory tests using fruit flies, females that mated with TMT males died 37-64 per cent sooner than those mating with non-engineered males.

The team specifically chose venom proteins that target invertebrates, making them safe for mammals and unlikely to harm beneficial insects.

Computer models suggest that using TMT on Aedes aegypti mosquitoes—which infect 390 million people with dengue fever annually—could reduce disease-spreading biting rates by 40-60 percent compared to existing methods.

"As we've learned from COVID-19, reducing disease spread as quickly as possible is important to prevent epidemics," says Beach.

The technique requires further testing before field implementation, with researchers expecting practical applications in three to five years.

Grapes of Math: Quantum Breakthrough, by Fran Molloy.

Macquarie University researchers have demonstrated how ordinary supermarket grapes can enhance the performance of quantum sensors, potentially leading to more efficient quantum technologies.

New research published in Physical Review Applied shows that pairs of grapes can create strong localised magnetic field hotspots of microwaves, a finding that could help develop more compact and cost-effective quantum devices.

A close up of a machine with a green butterfly on it

Image from https://www.eurekalert.org/multimedia/1054310

"While previous studies looked at electrical fields causing the plasma effect, we showed grape pairs can also enhance magnetic fields, crucial for quantum sensing applications," says lead author Ali Fawaz, a quantum physics PhD candidate at Macquarie University.

The research builds on viral videos showing grapes creating plasma in microwave ovens, but focuses on magnetic field effects relevant to quantum applications.

The team used specialised nano-diamonds containing nitrogen-vacancy centres—atomic-scale defects that act as quantum sensors—to detect magnetic fields. By placing their sensor on a thin glass fibre between two grapes and shining green laser light through it, they measured microwave field strength.

"Using this technique, we found the magnetic field becomes twice as strong when we add the grapes," says Fawaz.

Senior author Professor Thomas Volz says this research opens possibilities for quantum technology miniaturisation. The team used precisely sized grapes—each approximately 27 millimetres long—to concentrate microwave energy at the right frequency.

The researchers found water in grapes is better than traditional sapphire for concentrating microwave energy, though less stable—a challenge they're now working to solve.

Scientists engineer fish and flies to clean up toxic mercury, by Fran Molloy.

Macquarie researchers have engineered fish and flies with bacterial genes to convert toxic methylmercury into harmless gas, pioneering new pollution solutions.

Image from https://lighthouse.mq.edu.au/__data/assets/image/0017/1333430/700x400_Zebrafisch_Credit-Azul-Wikimedia_260841.jpg

Australian scientists have found an effective new approach to clean up methylmercury, one of the world's most dangerous pollutants that accumulates in food webs due to industrial activities like gold mining and coal burning.

The research, published in Nature Communications, shows how genetically modified fruit flies and zebrafish can transform methylmercury into a less harmful gas that disperses in air.

"It still seems like magic to me that we can use synthetic biology to convert the most environmentally harmful form of mercury and evaporate it out of an animal," says lead author Dr Kate Tepper from Macquarie University.

Methylmercury easily crosses the digestive tract, blood-brain barrier, and placenta, becoming increasingly concentrated as it moves up food webs, reaching highest levels in top predators including humans.

The team modified the animals' DNA by inserting bacterial genes to create two enzymes that convert methylmercury to elemental mercury, which then evaporates as gas.

Tests showed the modified animals had less than half as much mercury in their bodies, with most remaining mercury in a less harmful form.

"This approach uniquely addresses accumulated methylmercury that current bioremediation methods can't access once it enters food webs," says Dr Tepper.

Associate Professor Maciej Maselko, who supervised the research, notes that extensive safety testing is needed before any real-world application, but believes this approach shows promise for reducing mercury pollution in impacted ecosystems.