Majestic Monarch ButterfliesPosted in Wildlife A-Z | April 21, 2010 | Comment Now
Monarch butterflies are renowned for their mass migration. This migration brings millions of them to California and Mexico every winter. North American Monarchs are the only species of butterflies that undertake such a massive journey, which includes more than 3000 miles. The winters are particularly harsh; therefore, they need to make this journey every autumn.
Over the course of time, fattening larvae become juicy and colorful caterpillars. While they enter the pupa stage, they form a hard protective case around themselves. Their primary colors include black, orange, and white. This rich color pattern makes it easy to identify the monarchs. The unique colors warn predators that the insects are poisonous and inedible.
Monarch butterflies differ on the basis of their birth timing. Butterflies that emerge from chrysalides or pupa state in late summer or early fall are distinctly different from those that emerge in the longer, warmer days of summer. These butterflies are born to fly. They are guided by instinct to undertake a journey while the weather keeps changing.
Monarch butterflies born in late summer and early fall undertake the migration. They make a single round trip. When it is time for next year’s winter migration, numerous summer generations would have lived and died. These summer butterflies will be great grandchildren of last year’s migratory insects. These new generations of butterflies seem to know the way, and they follow the same routes of their ancestors. Some even return to the same tree.
Most researchers show concern overt the eastern population of monarchs, which inhabit the eastern Rocky Mountains. This group of monarchs is made up of small numbers. Its survival is threatened by natural disasters in the Mexican region. Decline in the number of milkweed plants also plays an important role.