An exoplanetary biosignature; the diplomacy of body odor; personalities of bees

This week, the Curiosity rover found large carbon deposits on Mars, suggesting an ancient carbon cycle. Researchers exploring the domestication of cats believe they may have originally pounced out of Tunisia. And researchers in Michigan report that during the shift of Earth’s magnetic pole 41,000 years ago, Homo sapiens may have protected themselves from harmful solar radiation with technologies including clothing, shelter and prehistoric sunscreen.

Additionally, a Cornell study found that personal odor was a strong predictor of friendship potential; astronomers reported the strongest evidence yet of an exoplanetary biosignature; and a German study found that beehive behavior is more strongly driven by individual personalities than previously understood:

Scientists say friends smell good

In a study of heterosexual women, Cornell researchers found that two people judge within minutes whether they have the potential to be friends, and that personal odor is a strong predictor of whether two people might engage with each other. At an in-person orientation, the researchers took participants’ photos; additionally, participants were issued T-shirts to wear for 12 hours. Later, each participant engaged in an online session in which they made snap judgments about the friend potential of the other participants’ photos.

At a second in-person session, participants sniffed T-shirts and evaluated the scent for friendship potential. Subjects then attended an in-person “speed friending” event in which they each spoke with 10 people for four minutes each. This event was followed by another T-shirt scent evaluation session. The researchers found that the smell-only evaluations were highly similar to the in-person evaluations, a demonstration of the power of what scientists call “diplomatic odor.”

Jessica Gaby, one of the researchers, says, “It’s not just perfume. It’s your dietary choices. Are you a cat person or a dog person? What laundry detergent do you use? All these judgments come together into what we call ‘diplomatic odor.’ You live in this odor space—does it match with the odor spaces of the people you interact with?”

Aliens smell like dimethyl disulfide

Researchers led by the University of Cambridge report the strongest signs so far of a biosignature outside the solar system. Using data from the James Webb Space Telescope, they found the chemical signature of dimethyl sulfide and/or dimethyl disulfide in the atmosphere of exoplanet K2-18b, which orbits in the so-called “habitable zone” of its host star.

There is only a 0.3% probability that the observations occurred by chance, which scientists call a three-sigma level of statistical significance. To be classified as a scientific discovery, the astronomers need to meet the five-sigma level, or below a 0.00006% probability that the observations occurred by chance. The team says further time with the JWST would enable them to meet this threshold.

This signal was first tentatively detected using JWST’s Near-Infrared Imager and Slitless Spectrograph and Near-Infrared Spectrograph instruments. The Cambridge team followed up with JWST’s Mid-Infrared Instrument and easily found the same signature. Professor Nikku Madhusudhan, from Cambridge’s Institute of Astronomy, who led the project, said, “This is an independent line of evidence, using a different instrument than we did before and a different wavelength range of light, where there is no overlap with the previous observations. The signal came through strong and clear.”

Bees have personality

Researchers in Germany report that the likelihood that a bee will choose to attack an intruder or hesitate is dependent on individual personality. Due to the distribution of tasks in a hive, the researchers assumed that pollen collectors would be less likely to sting than guards. The question they wanted to explore was how bees decide whether or not to sting.

They used a humane approach to test honeybees, which lose their stinger and die after attacking; the bees were provoked to attack a test dummy made from material in which the stingers wouldn’t stick. Thus, they were able to test the same bees over multiple trials. Test conditions included grouping bees with conspecifics to determine whether conformism contributed to the likelihood of stinging; others tested whether the concentration of alarm pheromones was a factor.

Neurobiologist Morgane Nouvian says, “Ultimately, it turned out that although these factors had an influence, they did not impact the predictability of individual stinging behavior.” The researchers conclude that the bees’ individual personalities prevailed over factors like conformism and group composition.

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