Pollen grains of genetically modified corn (Bt Corn), are proving to be fatal for the larvae of monarch butterflies ( Danaus plexippus ). According to a latest study conducted by John Obrycki of the Iowa State University, monarch butterflies die when they eat the corn pollen, which contains bacterial toxins. The pollen when dispersed by the wind lands on other plants, including milkweed (species of Asclepias ), which is the exclusive food of the monarch caterpillars. Milkweed is commonly found around cornfields. The researchers placed milkweed plants in and around a cornfield to see how much pollen the plants would collect. They found that at least 20 per cent of the larvae died when exposed to the milkweed leaves.