You might have missed: red flags; 300,000 years-old spears; robotic cameras; and plastic-free vegan leather

Cosmos Magazine


Cosmos is a quarterly science magazine. We aim to inspire curiosity in ‘The Science of Everything’ and make the world of science accessible to everyone.

By Cosmos

New privacy-preserving robotic cameras

Appliances with in-built cameras are becoming increasingly common in homes and workplaces. But these internet-connected devices come with the real risk of private images and videos being accessed by third parties.

Researchers at the Australian Centre for Robotics have created a new approach to restoring this privacy by designing cameras that process and scramble visual information before it is digitised –within the optics and analogue electronics of the camera itself.

“When we think of ‘vision’ we think of it like a photograph, whereas many of these devices don’t require the same type of visual access to a scene as humans do,” says Adam Taras, who completed the research as part of his Honours thesis.

“They have a very narrow scope in terms of what they need to measure to complete a task, using other visual signals, such as colour and pattern recognition.

“If these images were to be accessed by a third party, they would not be able to make much of them, and privacy would be preserved.”

A video demonstrating what a normal camera of smart technology like robotic vacuum cleaners sees, compared with the technique developed by the researchers. Credit: University of Sydney, Queensland University of Technology

Red flags! Why birds don’t eat matador bugs

Matador bugs (Anisoscelis alipes) are renowned for the colourful red adornments on their hind legs, which they tend to wave around. But until now, scientists haven’t understood the exact purpose of the behaviour.

To address this question, researchers from the Smithsonian Tropical Research Institute in Panama observed how predatory birds behaved when presented with true matador bugs and crickets that had matador bug flags attached to their legs.

Photograph of an black and orange bug sitting on a green leaf. The bug has large red, leaf-like projections on its hind legs
Both male and female matador bugs show off and wave their pretty red hindleg flags, prompting researchers at the Smithsonian Tropical Research Institute to ask why. Credit: Ana Endara/STRI

According to their new paper in the journal Behavioural Ecology, the flags signal to birds that matador bugs aren’t a delectable or safe choice for their next meal.

“I was fascinated to see that when we outfitted tasty crickets with the matador bug flags they immediately became less appealing to their bird predators,” says lead author Dr Juliette Rubin.

“This warning signal is enough to make the birds cautious but bugs themselves are so well equipped with ‘don’t eat me!’ signals that even without the flags, experienced birds wouldn’t touch them.”

Wooden spears allow a peak back into human history 300,000 years ago

In 1994, archaeological excavations in the Schöningen open-cast coal mine in Germany led to the discovery of the oldest, remarkably well-preserved hunting weapons known to humanity.

Spears and a double-pointed throwing stick were found between animal bones about ten meters below the surface, in a layer dating from the end of a warm interglacial period 300,000 years ago. 

Now, an interdisciplinary research team examining the objects using state-of-the-art imaging techniques – such as 3D microscopy and micro-CT scanners – has provided unique insights into Pleistocene woodworking techniques.

Sticks of varying length laid out on a black background
Eight spears (left) and six throwing sticks (right) from the Schöningen site, which were used for hunting large and small animals. Fragments were supplemented with drawn elements. Credit: Volker Minkus/MINKUSIMAGES, Christa Fuchs, Matthias Vogel, with additional drawn elements by Dirk Leder, NLD

“There is evidence of much more extensive and varied processing of spruce and pine wood than previously thought,” says first author Dr Dirk Leder from the Lower Saxony State Office for Cultural Heritage in Germany.

“Selected logs were shaped into spears and throwing sticks and brought to the site, while broken tools were repaired and recycled on site.” 

The research is published in the journal PNAS

Plastic-free vegan leather grown from bacteria

Researchers have genetically engineered bacteria to grow animal- and plastic-free leather that can dye itself, according to a new study in the journal Nature Biotechnology.

They created the self-dyeing leather alternative by genetically modifying the bacterial species Komagataeibacter rhaeticus, which produces sheets of bacterial cellulose – a strong, flexible and malleable material. The new genetic modifications instruct the microbes to also produce a dark black pigment called eumelanin.

Photograph of a black faux-leather wallet
A black wallet made by growing two separate cellulose sheets, cutting them to size, and sewing them together. Credit: Tom Ellis/Marcus Walker/Imperial College London

To produce a prototype shoe, the researchers grew a sheet of bacterial cellulose in a shoe-shaped vessel for 14 days. They then subjected it to two days of gentle shaking at 30°C to activate the production of black pigment.

“Our technique works at large enough scales to create real-life products, as shown by our prototypes,” says co-author Dr Kenneth Walker, who conducted the work at Imperial College London in the UK.

“From here, we can consider aesthetics as well as alternative shapes, patterns, textiles, and colours.”

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