The diet of monarch larvae is almost exclusively limited to plants within the Asclepias genus, commonly known as milkweed. This specialized herbivory is crucial for their development, as the caterpillars sequester toxins from the milkweed, rendering them unpalatable to many predators. Without access to milkweed species, monarch caterpillars cannot survive and metamorphose into adult butterflies.
This highly specific dietary requirement has significant implications for monarch conservation. Habitat loss, particularly the reduction of milkweed availability due to agricultural practices and urbanization, directly threatens monarch populations. The presence of milkweed is the primary limiting factor in many areas, determining the success or failure of monarch breeding cycles. Historically, diverse milkweed patches supported robust monarch populations, but current land management practices have drastically diminished these crucial resources.
