EAST LANSING, Mich (WLNS) – Researchers at Michigan State University are looking into the question of why the monarch butterfly is on the decline all across the U.S. and Mexico.
Researchers say there are several factors that could be contributing to the problem including herbicides that target milkweed plants, crops planted along their migration route and climate change.
Monarchs east of the Rocky Mountains take several generations to finish their regular migration from Canada to Mexico so the researchers say broad conservation efforts will be needed to preserve this pollenating species.
Monarchs west of the Rockies overwinter along the Pacific coastline of California and move inland in the spring to reproduce.
These populations have declined 80 percent across many of California’s overwintering sites.