Monsanto said it will donate $3.6 million to the National Fish and Wildlife Foundation's Monarch Butterfly Conservation Fund.
The company also will pledge $400,000 to aid experts and groups working on the butterfly’s behalf.
Environmentalists and scientists say the species has experienced a 90 percent decline in population. Most of the decline is blamed on habitat destruction, due in part to weed killers and herbicide-resistant plants like those Monsanto and other agribusinesses offer.
Orange-and-black spotted monarchs – renowned for migrating thousands of miles over many generations from Mexico, across the United States to Canada, and then back again – have seen their numbers fall dramatically in recent years.
The monarch population has plunged from 1 billion butterflies in 1997 to 56.5 million, the second-lowest number ever recorded, according to the Natural Resources Defense Council (NRDC).
The environmental group sued the EPA for failing to heed warnings about the dangers to monarchs posed by glyphosate, the key ingredient in Monsanto’s Roundup and other herbicides.
The application of glyphosate to farm fields has destroyed the milkweed habitat that migrating monarchs rely on, the suit states.