These butterflies are common in tropical places all over the world. One of the most famous butterflies, the Monarch ("Danaus plexippus"), belongs in this subfamily. The larvae and the butterflies get poisonous glycosides from their larval host plant, the milkweed, so they become distasteful to predators. These milkweed butterflies (Monarch, Queen, Soldier) eat only milkweeds ("Asclepias") as larvae. This highly effective defence strategy shields them against almost all predators. Birds soon learn to avoid these species after attempting to eat them.