Monarch Butterfly

The Monarch Butterfly (Danaus plexippus) is a large migratory butterfly native to the Americas, recognizable by its vivid orange wings veined in black with white-spotted borders. It is one of the few insects capable of transoceanic migration, with the eastern North American population traveling up to 4,500 kilometers each autumn from breeding grounds in Canada and the United States to overwintering forests in the Transvolcanic Belt of central Mexico, according to WWF and the IUCN. Western populations overwinter along the California coast, while non-migratory populations persist year-round in parts of Central America, the Caribbean, and introduced ranges across the Pacific.

Monarchs are obligate milkweed specialists: females lay eggs exclusively on plants in the genus Asclepias, and larvae feed on milkweed foliage, sequestering toxic cardenolides that render both caterpillars and adult butterflies unpalatable to most predators. As adults, they are significant pollinators of wildflowers across their broad breeding range. The IUCN Red List, which assessed the migratory monarch population as Vulnerable in 2022, identifies the primary threats as habitat loss through milkweed elimination driven by herbicide use and agricultural expansion, deforestation and degradation of overwintering forest in Mexico, and climate-driven disruption to migration timing and breeding phenology.