The other day I was watching this new series called Migrations on national geographic and I was rather intrigued by it. I wondered why man traveled from the African continent to other parts of the world - shortage of food, adverse climate or just an adventurous impulse? But eventually, after years of traveling and migrating from one place to another , he chose his home and continued to live there.
Imagine if we like animals, birds and insects had to migrate annually from one place to another without planes, or trains or buses but on foot, in search of food and a suitable place to live for that particular season, were hunted down by predators or had to hunt down our own prey. Agreed, we evolved… But isn’t it amazing how these creatures travel such great distances; no matter what they are faced with, they keep moving.
Of all migrations by small tiny creatures, very few are as astonishing as the one performed by the Monarch butterfly. Danaus plexippus is the only insect which migrates and is the longest migrating creature on earth that travels nearly 3000 miles as a group over several generations. They have orange reddish wings, with a wingspan of only 3-4 inches and weigh not less than half an ounce. Their larvae feed on the milkweed and the latex of which makes the adults poisonous to their predators. Their journey is often considered evocative of the flight of the daughters of the King of Libya who fled from Libya to Greece to avoid marrying their cousins. Their migration is of due importance as these butterflies pollinate many plants on their route.
Like several species of birds , bats and other animals, the Monarch of Canada and United States migrate to warmer places in Central Mexico and California as the winters in Canada and Northern America are very severe. Owing to their inability to survive such extreme snowfall and the lack of food, they head southwards each winter so that they can return to favorable sites in north America to reproduce.
What is most remarkable is that the Monarchs, which arrive at their hibernation sites in Mexico, are actually the great-great-great-grand children of those that started the journey from the north. There are nearly 3-4 or even more generations, which live for only four-five weeks but a unique generation is born which performs the migration from the northern region to Mexico which lives for nearly 6-8 months.
These tiny little creatures have an internal biological clock in their tiny little brain which functions along with the position of the sun and the earth’s magnetic field to guide them during their journey. The antennae of these insects function similar to a global positioning system in a car and the 24-hr clock actually resides in the antennae itself. The insect’s ability to sense magnetic fields was linked to two forms of a photoreceptor protein cryptochrome, which is similar to proteins found in migratory birds. Recent research has also found that butterflies’ migratory instinct to orient themselves to the sun is linked to 40 different genes passed along from generation to generation.
The whole episode of migration of these insects is very fascinating but they are faced with many difficulties too…predators , climate change and the biggest danger of all - humans. Yet these creatures migrate and they migrate in millions, but survive as one.
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