The monarch is probably the best-known butterfly in the world, famed for the beautiful orange and black hues of its wings and its even more remarkable trait of undertaking an annual migratory journey of thousands of kilometres across North America.
Although millions of monarchs exist and the insect is not considered to be in danger of extinction, a new report warns that the butterfly's migration as a natural phenomenon is imperilled because of threats to its habitat. These include the widespread spraying, by farmers and municipal weed-control workers, of herbicides that kill the milkweed on which the monarch's larvae feed. Another problem is the conversion of fallow land into urban sprawl.
The migration of monarchs is “among the most spectacular and unusual of the world's natural events,” says the report, but its decline “is certain unless these threats are addressed.”
The report, issued by the Commission for Environmental Cooperation, the Montreal-based conservation watchdog for the North American free-trade agreement, also says Canada, the U.S. and Mexico each have a responsibility to protect the insect.