Migrant butterflies create a flutter

ANJURULI (IDUKKI DISTRICT), April 30, 2014
Giji K. Raman

The summer showers have brought with it seasonal visitors to the Idukki wildlife sanctuary. With their yellow colour and rhythmic movements, the medium-sized butterflies known as Lemon Emigrant are creating quite a flutter on the river banks of the sanctuary.

Lemon Emigrant, also known as Common Emigrant (Catopsilia pomona), is a medium-sized butterfly of the pierid family found in Asia and parts of Australia. They migrate in groups and aggregate on substrates such as wet soil — a phenomenon termed ‘mud puddling’.

Entomologist Unni Krishnan Pulikkal who had held a survey of butterflies in the sanctuary told The Hindu on Wednesday that the species was very common in sanctuaries in the State. A large number of the common emigrant is found in the Chinnar wildlife sanctuary. They usually appear prior to the monsoon season and are spread over in the river line areas of the forest.

He said mud-puddling was a good sign. Some rare species of butterflies were also found in the sanctuary recently, pointing to the favourable atmosphere here for different species. The sanctuary also has host plants of various species, setting favourable conditions for the common emigrant.

The butterflies travelling up and down, using the rivers as corridors for high and low elevation breeding plants, is a common sight here. They settle down for long periods on sunlit river banks and sand bars to suck in mineralised moisture. Their unity in movements and common yellow colour against the sunlit river banks make for a visual feast. They also visit the flowers nearby on their migratory trail. The six Catopsilia species found across the world are gorgophone, thauruma, pyranthe, scylla, florella and pomona. Pomona is spread from Sikkim to Malaysia, east to the Philippines and from South Pacific to Australia.

Though earlier entomologists had considered Catopsilia pomona and Catopsilia crocale to be separate species, scientific studies later proved that they are of the same species. The eggs are laid in small batches on the food plants mainly of cassia genus.

 The Hindu, April 30, 2014