Monarch Butterflies in Sonora and Adjacent Northwestern Mexico

Monarch butterflies (Danaus plexippus) in Sonora, Mexico, exhibit limited breeding activity and distinct migration patterns that suggest minimal connection to the eastern North American population. Observations indicate monarchs breed on Asclepias species in Sonora but do not migrate eastward toward overwintering sites in Michoacán, as previously hypothesized. Instead, they follow a north-south route along the Río San Pedro and Río Sonora, dispersing into arid habitats and urban gardens. The Sierra Madre Occidental acts as a migration barrier rather than a corridor, isolating the Sonoran population from broader migratory routes. This study synthesizes historical records, tagging data, and ecological observations to clarify monarch movement in this region.

Van Devender, T. R., & Reina-Guerrero, A. L. (2022). Monarch Butterflies in Sonora and Adjacent Northwestern Mexico. Dugesiana, 29(2), 181–193. https://doi.org/10.32870/dugesiana.v29i2.7249