By Gayanga Dissanayaka –
Butterflies, who are truly a natural wonder on this island, are often taken for granted and rarely given the attention they should apart from admiring their aesthetic beauty. One of the main reasons to give attention to the conservation of these fragile creatures is because they play a vital role in the balance of nature. Sri Lanka hosts 248 known species of butterflies, 31 of which are endemic. Due to their strong independence with flowering plants, they are essential for the healthy ecosystem of the island, contributing to pollination, acting as indicators of environment health, supporting food webs, and enriching biodiversity.
In this month’s lecture at the Wildlife and Nature Protection Society (WNPS), Dr. Himesh Jayasinghe, who is the founding member and first president of the Butterfly Conservation Society of Sri Lanka, explained the intricate relationships between butterflies and plants and how that relationship contributes to the welfare of the ecosystem in Sri Lanka.
How did butterflies come to be?
According to Jayasinghe, butterflies, whose ecology is mainly centred around plants, play an important role as “primary consumers” in the food chain and also interact only with special kinds of plants. Throughout evolution, initially they fed on primitive plants such as Mosses and Lichens, then they moved on to the next stage which were Ferns. After that, they moved on to the Gymnosperms which were plants that don’t bear flowers but create seeds. “There’s still one butterfly in Sri Lanka who uses that group of plants but all the other butterflies are entirely feeding on flowering plants not only during the adult stage but during the lava stage as well.” said Jayasinghe.
According to research, Jayasinghe mentions that it’s clearly noted that when flowering plants are increasing, butterfly diversity also increases. Bees, according to research, evolved much earlier than butterflies, therefore the colours of the flowers are also evolved to utilise the usage of bees. In spite of that, later the butterflies used that opportunity to feed in flowering plants which is the main reason as to why butterfly diversity increased after the increment of flowering plants.
Distribution of butterflies in Sri Lanka
Jayasinghe pointed out in his presentation that the distribution of butterflies is largely determined by the distribution of their Larval food plants and this distribution is determined by various environmental factors such as rainfall, temperature, soil, slope and shade. There are also seasonal variations in populations which are determined by rainfall patterns. Jayasinghe mentioned that one would not find many butterfly variations in the wet zone but butterflies can be seen flying during seasons at dry zones.
He further explained that usually in tropical countries, eggs stay about two to three days and then the Larva stays about three weeks. After that the Pupa stage arrives which stays around three to four weeks. He also mentioned that these time periods may vary according to the species. During this life cycle, there are two stages in which they feed on plants, which is the Larva stage and the adult stage. But the preferences during these two stages are different as he mentions that in the Larva stage it chews but during the adult stage it only consumes the liquid.
Butterflies and their plants
“Now we have documented around more than 500 species that lay eggs. But they do not lay eggs in every plant since they have a very specialised group of plants to lay their eggs”, said Jayasinghe. He further explained that most of the butterflies have about three to four types of plants to lay their eggs but there are certain butterflies that lay only on a single species of plant, which makes them quite rare such as “Small Leopards” and “Silver Forget-me-nots”. The Small Leopards for an example only lay their eggs in a plant that is endemic to the Knuckles Range which hasn’t been recorded for around 150 years since it’s a very rare plant. Due to this reason, these butterflies are critically endangered species as well.
The preferences of butterflies
“During the adult stage, the butterflies don’t have specific types of plants to feed on,” said Jayasinghe. “They have plants that they prefer but they aren’t restricted to anything in particular” He explained that most butterflies prefer cluster flowers while some other butterflies such as “Skipper butterflies” prefer flowers with longer tubes that typical butterflies cannot access. There are also unique plants such as the “Mussaenda” which are evolved to attract butterflies. Such plants are very rare since most plants that are pollinated by butterflies are pollinated by bees as well.
Taking steps for butterfly conservation
According to Jayasinghe’s presentation, the butterfly-plant interaction determines the distribution and abundance of species and is required for the survival of both. It also emphasises the need for conservation of specific habitats. Jayasinghe also pointed out that butterfly gardening can be used for conservation as well. He also explained that the reason for fewer endemic butterflies in Sri Lanka is because of the lack of taxonomy studies conducted on butterflies. But the larger issue according to him is that now we are getting more and more data on the arrival of plants to Sri Lanka. Most of these plant lineages are very young and the recent species of butterflies that we have might not have enough time to evolve as different species.
To the question of implementing more butterfly gardens where there would be a biodiversity win in butterfly preservation and a human win with stress reduction and aesthetic beauty, Jayasinghe mentioned that these are good ideas both for conservation and for the general public as well. However he added that the legal aspects of these butterfly gardens would need to be handled together with the Department of Wildlife.