The butterfly effect
View(s):Constantly changing weather patterns have put a dent in the number of these flying insects
By Kshanika Goonesekera
Sri Lanka has been experiencing a change in weather patterns in the past few years where annual temperature mean has increased from 270C in the early 1990s to 290C in the 2000s. This has affected us, but what about other living creatures? In a study of butterflies conducted in several protected forest reserves around the island, funded by the National Research Council, Sri Lanka (NRC), the unreliable nature of the rains proved most deleterious during the months of 2012. The sudden floods and then absence of rains when there should have been precipitation resulted in a complete lack of these beautiful flying insects in the months of April and May 2012 which is considered the butterfly season.
A Lemon Immigrant
A visit to the Mithirigala Forest Reserve in the Gampaha district during the first few months of last year reported a solitary Ceylon Birdwing, a few Tree Nymphs and a Clipper apart from the ever present Psyche; ideally, this is when the forest should have been teeming with butterfly life.
These months are known to display the rare and endemic Cingalese Bushbrown (Mycalesis rama) categorised as Endangered by the 2012 National Red List. Unfortunately except for a single occasion in March after a sporadic spell of rains this particular butterfly has not been spotted. The Cingalese Bushbrown is described as rare by past lepidopterists such as de Niceville (1899), d’Abrera (1998), Ormistan (1924) and even Woodhouse (1950) and was spotted in bamboo forests of Sri Lanka. Of course the bamboo forests are fast dwindling and have lessened considerably over the last few decades.
The Mithirigala Forest Reserve and the Dombagaskanda Forest Reserve of the Kalutara district are two protected forests close to city limits. It is to this forest that the Cingalese Bushbrown has been attracted to in the past.
Trying not to lose hope we ventured once again in to the Mithirigala Forest Reserve in early June last year hoping that the sudden appearance of the rains would have coaxed life back in to the forest. Relative humidity had risen to 100%, temperatures ranged from 260C to 280C, there was no shortage of leeches and so too the butterflies. Six Blue Mormons flitted from one tree to the next displaying territoriality by chasing each other away. A male and female Ceylon Birdwing danced around each other engrossed in a courtship ritual close to some Clidemia hirta also known as Soap Bush or Koster’s curse. Clippers were in abundance together with the Common Rose, Common Mime, Grey Pansy, Plum Judy, Metalic Cerulean, Angled Pierrot, Common Bluebottle, Tailed Jay and the Chocolate Soldier. Everyday species of Psyche, Common Grass Yellow,among others were also spotted flitting about the road side.
Reinitiating our field visits in 2013 with the improved weather conditions we were truly amazed at the wonders of nature. The home gardens surrounding the Dombagaskanda Forest Reserve were filled with groups of Common Grass Yellows, Blue Glassy Tigers, Common Ceruleans and Tiny Grass Blues flitting about. A solitary Common Rose followed us about while a Common Indian Crow decided to observe us from a distance.
Special permission from the Forest Department is required to enter these forest reserves but it is definitely worth the trip to witness such beauties in their natural habitat, especially since the rains have started once again. Hopefully the Cingalese Bushbrown will decide to make an appearance soon.
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