THE CUTTING EDGE
Ancient DNA reveals new insight on Vikings
One of the most sweeping genetic surveys of ancient DNA ever done offers some surprises about the people we call Vikings.
Ninety researchers, led by Eske Willerslev of the University of Copenhagen, reported in the journal Nature on their analysis of the genomes of 443 ancient humans from Europe and Greenland. They found considerable genetic variety in the remains, indicating migration of Southern Europeans, before the Viking Age of roughly 750 to 1050, to the area of Denmark.
“There’s a story behind that,” he said, “ ‘Saving Private Ryan’ or something.”
Joshua trees temporary declared endangered
California officials took the unusual step of granting temporary endangered species status to the western Joshua tree, but will allow 15 solar energy firms to raze Joshua trees that stand in the way of their shovel-ready projects.
The action reflects a difficult reality: Climate change represents a clear threat to both public health in California and to the long-term sustainability of the western Joshua tree. Supporters claim that Yucca brevifolia faces the threat of extinction due to climate change, wildfires and habitat destruction from urban sprawl.
Why some bees have larger brains than others
Panurgus banksianus, the large shaggy bee, lives alone, burrowed into sandy grasslands across Europe. It prefers to feed on yellow-flowered members of the aster family.
The large shaggy bee also has a very large brain.
In a study published in Proceedings of the Royal Society B, scientists scrutinized hundreds of bee brains. Bees with specialized diets seem to have larger brains, while social behavior appears unrelated to brain size. That means when it comes to insects, the rules that have guided brain evolution in other animals may not apply.
Ferran Sayol, an evolutionary biologist at University College London, and his co-authors studied brains from 395 female bees belonging to 93 species from across the U.S., Spain and the Netherlands.
One pattern that emerged was a connection between brain size and how long each bee generation lasted. Bees that only go through one generation each year have larger brains, relative to their body size, than bees with multiple generations a year.
Looking at the bees’ diets revealed a more surprising tendency. In birds, “we know that species that have a broader diet tend to have bigger brains,” Sayol said. The challenge of finding and consuming a wide variety of foods may demand a large brain. However, Sayol said, “We found the opposite in bees.” The biggest brains were in dietary specialists, such as the aster-loving large shaggy bee.