Milkweeds and butterflies often form mutually beneficial relationships. What is advantageous and protective to the Monarch butterfly, for example, can be deadly to other small insects. Caterpillars feed on certain poisonous milkweeds which make them harmful to birds. Milkweeds have their pollen clustered in masses called pollinia but only the stronger, larger individuals can manipulate a flower to extract the pollen without getting tangled and trapped in the complex floral architecture.
DISTRIBUTION: Locally common in many habitats (incl. fields and roadsides) throughout Calif.; 0-1900 m.
