GM crops driving Monarch butterflies' decline

The iconic monarch butterfly, once common across the US, could soon end up on the Endangered Species List due to the growing use of genetically modified (GM) crops in the country, scientists say.
By some estimates, the population of the black-and-orange butterflies has declined by 90 per cent over the past two decades, from about 1 billion butterflies in the mid-1990s to just 35 million individuals.
That loss is "so staggering that in human-population terms it would be like losing every living person in the US except those in Florida and Ohio," Tierra Curry, a senior scientist at the Centre for Biological Diversity, was quoted as saying by Live Science.

According to the scientists behind a petition that asked for including monarch butterfly in the list of endangered species, many crops are altered to be resistant to Monsanto's Roundup herbicide which kills milkweed, the monarch caterpillar's only source of food.
The herbicide is so successful that milkweed plants have virtually disappeared in Midwestern corn and soybean fields, and monarch butterflies have effectively lost a Texas-size chunk of their habitat, according to the petition.