You may have missed… ants playing dead; wildlife on the dark web; the “sweatainer” collects your sweat; and ancient wine grapes

These ants “play dead” to avoid predators

In what Australian researchers believe is a world first, a species of ant on Kangaroo Island in South Australia has been observed exhibiting an unusual behaviour – playing dead.

It was accidentally discovered as UniSA researchers were checking pygmy-possum and bat nest boxes, revealing a colony of Polyrhachis femorata ants that appeared to be dead… until one moved.

Described in a new study in the Australian Journal of Zoology, this is the first time that a whole colony of ants has been recorded feigning death.

Four polyrhachis femorata ants feigning death.
Polyrhachis femorata feigning death. Credit: S. ‘Topa’ Petit

“This sort of defensive immobility is known among only a few ant species – in individuals or specific casts – but we don’t know of other instances when it’s been observed for entire colonies,” says Associate Professor S. ‘Topa’ Petit, a wildlife ecologist at UniSA and first author of the paper.

“In some of the boxes containing colonies of Polyrhachis femorata, some individuals took a while to stop moving, and others didn’t stop. The triggers for the behaviour are difficult to understand.”

Illuminating illegal wildlife trade on the dark web

Wildlife is traded on the internet, with people buying and selling live animals, plants, fungi, and their parts and products online. But how much of this is being done on the dark web?

In a new study in the journal People and Nature, University of Adelaide researchers trawled a database of more than 50 dark web marketplaces and identified 153 species being traded.

“While we did find small numbers of animals traded, the vast majority of advertisements were for plants and fungi,” says Dr Phill Cassey, from the Invasion Science and Wildlife Ecology Lab at the University of Adelaide’s Environment Institute, Australia.

“Most plants were advertised for their use as drugs, often as psychedelics, but some for their purported medicinal properties,” says Cassey, who is senior author on the paper.

“Fungi and animals were also traded for use as drugs, including the infamous Colorado River toad, which is known for its ability to exude toxins from glands within its skin that have psychoactive properties.

A green toad with yellow eyes sits on a rock
Colorado River toad (Incilius alvarius). Credit: Mirko_Rosenau/Getty Images

“While wildlife is being commonly traded on the dark web, it is mostly for use as drugs and medicine, and not for other related trafficking crimes – for example, live exotic pets.

“This is important for understanding threats to biodiversity (unsustainable harvesting of wildlife) and biosecurity (illegal transport of pests, weeds and diseases) across international borders.”

3D-printed wearable sweat sensor called the “sweatainer”

Sweat can hold vital health information and monitoring it can provide insight into dehydration, fatigue, and blood sugar levels. Now, an innovative 3D-printed wearable sweat sensor, called the “sweatainer”, has been developed to expand upon the capabilities of wearable sweat devices.

“Sweat is a really rich biofluid,” says Tyler Ray, assistant professor in the Department of Mechanical Engineering at the University of Hawaii at Manoa. “It allows us to have a non-invasive window into the body to really understand a person’s physiological health state and so if we want to look at disease states like cystic fibrosis or diabetes we have access to the body in a way that would be similar to what we’d get through blood draws.”

The sweatainer is a triangular patch on a person's forearm, with small twisting channels filled with a green liquid
Sweatainer on a person’s arm. Credit: Roxanne Kate Balanay/Tyler Ray

Ray is senior author of a paper describing the technology in Science Advances.

This epifluidic device uses skin-compatible adhesives to collect sweat directly from sweat gland, in a “multi-draw” sweat collection method – this allows for multiple, independent sweat samples for analysis.

“3D-printing enables an entirely new design mode for wearable sweat sensors by allowing us to create fluidic networks and features with unprecedented complexity,” adds Ray.

A genetic link between red and white grapes more than 1100 years ago

A new study analysing DNA from ancient winegrape seeds discovered at archaeological excavations in the Negev Desert in southern Israel, has revealed a genetic link with modern varieties.

According to a new study in PNAS, the relatively well preserved seeds were discovered on the floor of a sealed room, which had provided protection from climatic phenomena such as extreme temperatures, flooding, or dehydration. 

Microscope image of grape seeds with a 5 milimetre bar for scale.
Microscope image of ancient wine grape seeds from Avdat, in southern Israel, with a 5 millimeter scale bar. Credit: Guy Bar-Oz/the University of Haifa

Two samples of the highest quality DNA, both from about 900 CE, were identified as belonging to specific local varieties which still exist today.

“One ancient seed was found to belong to the Syriki variety, still used to make high-quality red wine in Greece and Lebanon. Since winegrapes are usually named after their place of origin, it is quite possible that the name Syriki is derived from Nahal Sorek, an important stream in the Judean Hills,” say the researchers.

A second seed was identified as related to the Be’er variety of white winegrapes still growing in the sands of Palmachim on Israel’s seashore.

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