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A decapitated sea-slug head approaches its slightly reactive body.

A sea slug’s head chumms up with its still-living body, three days after it decapitated itself.Sayaka Mitoh

Why sea slugs cut off their own heads

Two species of sea slug, Elysia marginata and Elysia atroviridis, decapitate themselves — only to regrow a new body from the severed head. Researchers were astonished to observe slugs in captivity cutting off their own heads after their bodies became infected with parasites. Within 3 weeks, the heads regenerate a whole, parasite-free body, though the bodies never grow back new heads.

The New York Times | 5 min read

Reference: Current Biology paper

Cannabis, it’s a climate gas

Legal cannabis production in Colorado alone emits more greenhouse gases than does the state’s coal-mining industry. The energy required to yield one kilogram of dried flower from cannabis grown indoors generates the equivalent of 2–5 tonnes of CO2, depending on where the weed is grown. Most US cannabis is grown indoors under artificial lights, either for legal reasons or to avoid theft. “The profit margins are so huge that you don’t have to be making super energy-conscious decisions,” says Jason Quinn, who analysed the carbon footprint of the emerging US cannabis industry.

New Scientist | 3 min read

Reference: Nature Sustainability paper

Oldest-known wild bird has a new chick

A 70-year-old Laysan albatross with at least 30 offspring is a mother again. The Phoebastria immutabilis, dubbed ‘Wisdom’, nests on the Midway Atoll National Wildlife Refuge, alongside nearly 70% of all Laysan albatrosses. She was first ringed as an adult in 1956 by legendary ornithologist Chandler Robbins and is now the world’s oldest known banded bird in the wild.

The Guardian | 4 min read

COVID-19 coronavirus update

Pregnancy and COVID: what the data say

As the pandemic rolls on, evidence is building around the risk of COVID-19 to pregnant women.

• Pregnant women with COVID-19 seem to be at higher risk of hospitalization and severe disease than are women of the same age who are not pregnant.

• Samples from the placenta, the umbilical cord and blood from mothers and infants indicate that the virus rarely crosses from mother to fetus.

• Some preliminary data suggest that infection with the virus can damage the placenta, possibly injuring the baby.

• There is a lack of data around the safety of COVID-19 vaccines for pregnant women because this group generally was not included in early trials. But physicians contacted by Nature overwhelmingly say they would recommend that pregnant women be offered the vaccine after medical consultation, because of the risk presented by COVID-19 to them and their babies.

Nature | 11 min read

A graph that compares the percentage of pregnant women with and without COVID-19 affected by different clinical outcomes.

Source: Ref. 4

Pandemic prompts lab-supply shortages

Scientists around the world are scrambling to secure supplies of gloves, plastic tips for pipettes, centrifuge tubes and other laboratory basics. The pandemic has increased demand for testing materials while disrupting manufacturing and distribution channels. Some labs are also reporting problems with acquiring lab animals. Researchers are adapting by delaying experiments, swapping materials with colleagues and adopting a ‘reduce, reuse and recycle’ ethos.

Nature | 6 min read

Lipid shells are unsung heroes of mRNA vaccines

Tiny balls of fat called lipid nanoparticles (LNPs) make messenger RNA (mRNA) vaccines, such as those developed by Pfizer–BioNTech or Moderna, possible. LNPs protect the delicate mRNA as it enters the cell. “It is the unsung hero of the whole thing,” says Giuseppe Ciaramella, who was head of infectious diseases at Moderna from 2014 to 2018. But the technology spent three decades trying to prove itself.

Chemical & Engineering News | 12 min read

Image of the week

East crater of the Etna Volcano erupting with high lava fountains behind the Mother Church of Belpasso in Catania, Italy.

In this night-time shot of a church in Catania, Italy, forked rivers of lava can be seen pouring out of Mount Etna more than 25 kilometres away. Europe’s most active volcano began spewing ash, smoke and lava in mid-February, but volcanologists say this period of activity is unlikely to cause serious damage or injury. See more of the month’s sharpest science shots, selected by Nature’s photo team. (Nature | Leisurely scroll)Fabrizio Villa/Getty

Quote of the day

“These women are passionate about science and pick fields that they think will benefit society.”

Computer scientist Sana Odeh reflects on research exploring why most physics students in Muslim-majority countries are female. (Physics | 2 min read)

Reference: Physical Review Physics Education Research paper)