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It’s a boy!

In new research from the Australian National University, swift parrot mothers are choosing to hatch their sons earlier than their daughters, meaning they end up with more male offspring. This might seem surprising, because there are fewer female swift parrots than males, but it is actually a clever way of spreading genes.

Female swift parrots in Tasmania often get killed and eaten by invasive sugar gliders when they are looking after eggs, but the males don’t. The mother parrots help the male eggs hatch faster, so that they can grow bigger and stronger and fly around breeding with as many females as possible, suggests the paper published in Proceedings of the Royal Society B.

“Although favouring sons sounds counterintuitive, it makes evolutionary sense,” says Rob Heinsohn, the ANU professor who led the study.

“From an individual female’s point of view, there’s no point in producing more females if they are only going to be eaten. It’s far better to have sons early in the egg hatching sequence as the older chicks get more of the food and leave the nest fat and healthy. That gives them an advantage when they compete for a mate.”

Is your favourite coffee genetic?

People who are predisposed to high blood pressure naturally avoid coffee because of ‘protective’ genetics, suggests research from University of South Australia and SAMRHI. The paper, published in The American Journal of Clinical Nutrition, shows that the choice could be subconscious.

“People drink coffee for all sorts of reasons – as a pick me up when they’re feeling tired, because it tastes good, or simply because it’s part of their daily routine,” says Elina Hyppönen of the University of South Australia.

“But what we don’t recognise is that people subconsciously self-regulate safe levels of caffeine based on how high their blood pressure is, and this is likely a result of a protective genetic mechanism.

“What this means is that someone who drinks a lot of coffee is likely more genetically tolerant of caffeine, as compared to someone who drinks very little.

“Conversely, a non-coffee drinker, or someone who drinks decaffeinated coffee, is more likely prone to the adverse effects of caffeine, and more susceptible to high blood pressure.”

(Note from the Cosmos writer – given the amount of coffee consumption that happens in this office, I sincerely hope we’ve all got the right genes for it.)

This week in fish health

Credit: USC Australia

Fancy a morning seaweed smoothie? Maybe if you are a fish!

Researchers from the University of the Sunshine Coast found that feeding fish powdered seaweed, called Asparagopsis, could boost the immune system of rabbitfish.

“The seaweed quadrupled the immunity of the rabbitfish, meaning they were more likely to be resistant to pathogens down the track. We also showed that this seaweed is stronger than four immunostimulants currently used in aquaculture,” says Valentin Thépot, who led the study.

“This means that a seaweed-based feed additive could one day replace the use of veterinary drugs or antibiotics in aquaculture that can be detrimental to the environment, to animals and even to us as consumers.”

Fish have similar immune systems to other farm animals, so the seaweed feed immune boost could be applicable to them, too, according the paper, published in Fish and Shellfish Immunology.

“There is no reason that this immunostimulant effect would be limited to just fish,” says Thépot.

“It may be applicable to other agricultural industries, and different species of seaweed may offer other immune or production benefits. There is definitely scope for further research.”

Little punchers

Mantis shrimp just pack a punch from just 9 days old, according to a paper published in the Journal of Experimental Biology.

A microscope image of a mantis shrimp larva. It has a long protrusion from a shoulder.
15 day old Mantis Shrimp larva. Credit: Jacob Harrison.

Adult mantis shrimps have an explosive punch that splits water, but it appears that their 4.2mm long larvae start to punch around the time they begin feeding at 9 days. Their punch moves at ~0.385m/s, which is 5-10 times faster than the larval snacks they eat.

“The larvae can be incredibly tricky to collect,” says Jacob Harrison of Duke University, US, as he describes luring the babies into a net with a light. Annoyingly, a whole bunch of other critters liked the light and got in the net, too.

“It can be incredibly challenging to sift through a bucket teeming with larval crabs, shrimp, fish and worms to find the mantis shrimp,” laughs Harrison.

To actually study them with a camera, he says “I had to superglue a 4 mm sized larva onto a toothpick, place it on a custom-designed rig and orient the individual within view of the camera lens before I could even start collecting data.” (Note from the writer to me, the weirdest thing about this story is the method.)

“It took about a year to troubleshoot the right way to set up the camera before we knew that we could capture these videos.”

Future drones could look like 300 million year old dragonflies

Footage of dragonfly-inspired drone prototype designed and tested by UniSA researchers. Credit: University of South Australia.

The dragonfly proves to be a fantastic model for future drones because of its flappy wings, shape and gearing, suggests a paper published in Drones. (Note from the writer – Yes, there is a whole journal dedicated to drones. My current favourite paper from them is SeeCucumber: for seeing sea cucumbers.)

A team of PhD students from UniSA, led by Javaan Chahl, spent lockdown designing and testing dragonfly-inspired drones that could help deliver awkwardly balanced loads and explore sensitive natural environments.

“Dragonflies are supremely efficient in all areas of flying,” says Chahl.

“They need to be. After emerging from under water until their death (up to six months), male dragonflies are involved in perpetual, dangerous combat against male rivals.

“Mating requires an aerial pursuit of females and they are constantly avoiding predators. Their flying abilities have evolved over millions of years to ensure they survive,” (Note from the writer – This is my favourite quote from science news this week).

“They can turn quickly at high speeds and take off while carrying more than three times their own body weight. They are also one of nature’s most effective predators, targeting, chasing and capturing their prey with a 95 per cent success rate.”

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