Murderers in their midst

A yellow-legged hornet nest in Beaufort, South Carolina. The spread of yellow-legged hornets through the region is posing a threat to the local honey crop. — Sean Rayford/The New York Times

JACKIE Currie had never seen anything like it. She had raised bees in South Carolina for more than a decade, and her insects had almost always been eager to fly out and collect pollen.

But one day last summer, she found her bees huddled at the entrance of their hive, like frightened beachgoers after a shark attack.