The butterfly effect

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The butterfly effect

It is a phenomenon that has baffled naturalists. The migration of butterflies is perhaps one of Nature’s marvels

Photos: K. Ananthan

Spectacular show Snapshots from the butterfly migration at Anaikatty

It’s the magic of the monsoons. After the showers, the forest springs back to life and the celebrations begin. One of them is a spectacular show in colours — the migration of butterflies.

Lakhs and lakhs of winged beauties take this flight, from June to July and October to November to a secret destination, a mystery that scientists and naturalists have been trying to unravel over the years.

Last week, the campus of Salim Ali Centre for Ornithology and Natural History (SACON) in Anaikatty, near Coimbatore, took on a coloured hue as the winged visitors fluttered their way across the valley and the forest. “It was fascinating to see the huge flow of butterflies,” says P. Pramod, Nature Education Officer of SACON, who has been observing this wonder for the last eight years.

Chasing butterflies

Some of the common butterflies such as dark blue tiger, common crow, double banded crow and common albatross joined the party. And, lime butterflies, in a combination of yellow and greenish spots, crossed the valley in large numbers.

It is believed that this large scale migration is an act of dispersal. Butterflies reproduce in huge numbers and disperse the young ones to various locations. Naturalists in the region have come up with a clearer picture, based on the scattered information that has been collected from Nature lovers. Some of them track the areas where the migration happens and the direction the butterflies take. In the Western Ghats, it is noticed that the butterflies always travel from the South West towards the North East.

Various influences

In June and July, they fly from the Nilgiris ranges to the Velliangiri hill range and in October and November, it is in the opposite direction. “They basically travel in the opposite direction of the wind. This is one vital clue, but to confirm it, we need to carry out systematic and planned studies. Climatic and geographical conditions, humidity, wind movement, availability of plant species (their food) have a big influence,” Pramod explains.

Most of the butterflies are common species (resident butterflies) that flock and travel from one region to another. The blue tiger that sports bluish black lines is one of the primary migratory butterflies and it moves in large numbers during the season.

The journey begins after the sun rays hit them (all butterflies need to bask in the sun to dry their wings before they begin to fly) in the morning and continues till the afternoon. In the evening, they rest on trees, a beautiful sight to watch — an array of colours clinging to the trees.

Another significant aspect noticed in migration is ‘mud puddling’ — where male butterflies extract minerals and moisture from the wet soil that they transfer to the females during mating.

“This happens when the population is more; only those males with better minerals are chosen by female butterflies,” Pramod explains.

Butterfly migration is always associated with the monarch butterfly migration that occurs in the U.S. but the fascinating phenomenon has been observed and recorded in various regions of the country.

The Malabar Natural History Society has conducted planned studies in the Kerala belt, especially the northern regions such as Wayanad, Kannur, Kozhikode and Malappuram. Scattered information is available in Andhra, Karnataka and parts of Tamil Nadu.

Magical

So, what does the migration look like? “It is magical. In blues, yellows, greens and greys, thousands of them circle you and flutter away. It brings about a sudden change in the environment,” says R. Selvi, a Nature lover who teaches zoology at Kadri Mills Higher Secondary School.

“They go in one direction, fly at moderate heights and at normal speed. In 2006, we saw them pass our school campus by the thousands; common crows, common roses, lime butterflies and blue tigers,” she recalls.

Pramod says it’s an intriguing phenomenon. “Scientists look at it with wonder as there are a lot of unanswered questions — Where do such unimaginable quantities of plants to feed the larvae come from (every butterfly species feeds on a particular plant species)? How do the butterflies know their destination? And, what triggers their togetherness?”

K. JESHI