| sonous Milkweed is the primary food source for | | | | the adult butterfly. Birds, and other predators, |
| the Monarch Butterfly pupa, or caterpillar (which is | | | | eating Monarchs containing these poisons, can |
| classified as a specialist herbivore). Milkweeds are | | | | become very ill, possibly fatally so. The Monarchs |
| the only source of nourishment up until they are | | | | themselves (and some other insects) have |
| released from their cocoon (chrysalis) and | | | | developed immunity to these poison juices. |
| transformed (or undergo metamorphosis) into a | | | | Interestingly the Viceroy Butterfly, although not |
| butterfly. After transformation the adults drink | | | | containing toxins, has mimicked itself over time to |
| water and extract nectar from many kinds of | | | | look very similar to the Monarch, thereby |
| flowers. Monarchs do pollinate flowers, but not | | | | deterring many predators. |
| nearly as proficiently as bees. | | | | On the predator side, two species birds, the Black |
| The vast majority of all Monarchs in North | | | | Back Oriole and the Black Headed Grosbeak are |
| America make their home in agricultural areas | | | | not affected by the Monarch’s toxins, and |
| that are abundant with the milkweed plants | | | | are this butterfly’s main adversary. |
| whose leaves provide a safe place to deposit | | | | Varieties of milkweed are found abundantly, and |
| their eggs, and also to feed their offspring. When | | | | although the United States government has not |
| returning every spring from their winter migration, | | | | labeled the plant as poisonous or noxious, farmers |
| the butterflies will stop over at the resurging | | | | consider the plant a weed and a real nuisance to |
| milkweed and flowering plants and continue | | | | their livestock and crops. Farmers often apply |
| northward. | | | | herbicides to large acreages to kill unwanted |
| The overall milkweed plant family contains over | | | | vegetation. This has resulted in a very sizable |
| two thousand varieties. North America is home to | | | | decrease of the Monarch Butterfly’s |
| over 105 versions. The Monarchs lay their eggs | | | | source of the milkweed plant, especially |
| on several varieties, but seem to prefer the | | | | throughout the mid-western agricultural areas, |
| native, instead of hybrid, varieties. Many kinds of | | | | thereby affecting their summertime migratory |
| milkweeds found in North America contain poisons | | | | behavior. |
| and are toxic enough to harm livestock and other | | | | Scientists are now able to determine the |
| animals that have not learned through evolution to | | | | migratory paths of a Monarch Butterfly. An adult |
| avoid them. | | | | can be analyzed to determine exactly which |
| The milkweeds that contain bad tasting and bitter | | | | species of milkweed it fed upon earlier in its |
| heart poisoning ingredients (cardiac glycosides) are | | | | caterpillar state. |
| ingested by the Monarch larvae, and remains in | | | | |