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Migration of Butterflies 

Migration of Butterflies 

Context:

In August 2020, an unusual phenomenon took place when thousands of butterflies were seen traveling from the Eastern Ghats to the Western Ghats.

Details:

  • The two seasonal butterfly migrations is an annual event that occurs between the Western and Eastern Ghats of the Indian peninsula in search of food and survival.
  • The Nilgiris are one hub for the migratory butterflies. Lakhs and lakhs of butterflies fly through the Nilgiri hills from the Kallaru corridor and Thengumorahada.
  • Dark blue tiger, blue tiger, common crow, and double branded crow are the common migratory butterflies between the Ghats

Reasons for migration:

  • Intense rain: The intense rain in the Western Ghats complex during the southwest monsoon makes it difficult for the butterflies to survive.
    • Before the onset of the southwest monsoon, butterflies start their first migration from the Western Ghats to the plains and to the Eastern Ghats in order to avoid the inclement weather.
    • In the Western and Eastern Ghats, it is clear that altered rain patterns have affected the migration patterns of butterflies.
  • Ideal climate: The Eastern Ghats provide the ideal climate for the butterflies to survive during the southwest monsoon.
    • The migratory adults become reproductive, breed, lay eggs, and die the successive generation starts to migrate back from the Eastern Ghats.
    • The second migration took place early in 2020 due to heavy rainfall in the Eastern Ghats during the southwest monsoon.
    • The butterfly offspring population would not have been able to survive in the Eastern Ghats with unviable weather conditions and a lack of food, forcing an early migration.

Butterflies: Indicators of Climate Change:

  • The Butterflies are bioindicators and the early migration means an early arrival of monsoon.
  • With climate change altering weather phenomena across the world, tracking and studying seasonal butterfly migrations have assumed greater significance.
  • The butterflies originate from Western Ghats ranges, such as Kodagu, Wayanad, Nilgiris, Siruvani, and Anamalai, and move toward the Eastern Ghats consisting of Yercaud, Pachamalai, Kolli, and Kalvarayan hills during the first migration.
  • The migration between the Ghats is a form of local migration but other types of migration are also prevalent among butterfly species in the hills of peninsular India.

Source: Indian Express