In the hills of Mizoram state in north-east India, the first thing that farmers notice are the swarms of stink bugs, known locally as thangnang. It can mean only one thing: the rats are coming. And with them, famine.
As dawn breaks in Mamit district, Maunsanga, a 62-year-old farmer, walks across his plot, stopping where his rice crop once stood. He bends down to examine a broken stalk.