Sri Lanka is home to 245 species of butterflies with 23 of these being endemic to the island.[1] Of the 245 species, 76, are listed as threatened nationally, while the Ceylon rose is designated as critically endangered.[2]
See main article: List of butterflies of Sri Lanka.
The majority of species are found in the foothills (up to 3000feet elevation). A much smaller number of species are found above 4000feet, while 20 species of butterfly are restricted to the low lying dry zone (below 500feet elevation). The number of butterflies peaks in two seasons during the year. The first of these is during the southwestern monsoon in the months of March to April. The second is during the northeastern monsoon which continues from September to October.
| Feature | Butterflies | Moths | |
|---|---|---|---|
| Shape and structure of antennae | thin slender filamentous antennae which are club-shaped at the end | comb-like or feathery antennae, or filamentous and unclubbed | |
| Wing-coupling mechanisms | lack a frenulum | have a frenulum which is a filament arising from the hindwing and coupling (matching up) with barbs on the forewing. The frenulum can be observed only when a specimen is in hand. Some moths have a lobe on the forewing called a jugum that helps in coupling with the hindwing. | |
| Pupae | form an exposed pupa, also termed a chrysalis | moth caterpillars spin a cocoon made of silk within which they metamorphose into the pupal stage. | |
| Colouration of the wings | bright colours on their wings | usually plain brown, grey, white or black and often with obscuring patterns of zigzags or swirls | |
| Activity | diurnal | nocturnal and crepuscular | |
| Structure of the body | have slender and smoother abdomens | have stout and hairy or furry-looking bodies | |
| Scales | possess fine scales | larger scales on their wings which makes them look more dense and fluffy | |
| Appearance of eyes | apposition eyes | superposition eyes | |
| Resting posture | fold their wings above their backs when they are perched | rest with their wings spread out to their sides |
Within Sri Lanka, the latest revision of lepidopterans described 1903 species with 58 families of butterflies and moths. Out of these 1903 species, 208 species are butterflies and 1695 species are moths.
The family-wise number of butterfly species are:[2]
| Family | Species |
|---|---|
| Papilionidae | 15 |
| Pieridae | 27 |
| Nymphalidae | 69 |
| Lycaenidae | 86 |
| Hesperiidae | 46 |
| Riodinidae | 1 |
The first studies of Ceylon butterflies were published by James Emerson Tennent in Ceylon, Physical, Historical and Topographical based on work by Robert Templeton and Edgar Leopold Layard active in the 1840s. In these early years William de Alwis made watercolour illustrations of life histories. Later in the century this was followed by The Lepidoptera of Ceylon by Frederic Moore which was published in 1880. Pioneering studies based on field observations were published by Walter Ormiston, a tea planter from Kalupahani, Haldumille, in 1924, Lionel Gilbert Ollyet Woodhouse and George Morrison Reid Henry in 1942 and by Woodhouse again in 1950. Bernard d'Abrera published The Butterflies of Ceylon in 1998 based on examination of specimens in the Natural History Museum in London. Recently, papers have been published on status of particular butterfly families, check-lists of various localities, life-cycles and natural history as well as butterfly migration.[2]
In 2008, Dr. Michael van der Poorten discovered a new species of Sri Lankan butterfly, the first such discovery in 60 years.[3] The species has been identified as Catopsilia scylla.
Habitat destruction and degradation, air pollution, over-usage of pesticides, and over-exploitation for ornamental trade are the main threats to butterflies in Sri Lanka. Prolonged droughts and over-predation also pose a threat to them. Opportunistic predators such as ants and birds prey on butterfly eggs, caterpillars, pupae and adults. The Ceylon rose and Ceylon birdwing are presently included in the appendices of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). This United Nations initiative aims to protect these species against over-exploitation by restricting trade across borders.
A majority of endemic species are restricted to the wet zone forests. The Ceylon birdwing is one of the largest endemics of the country and is found in large numbers in the Sinharaja Forest Reserve.[4]
| Common name | Binomial name | |
|---|---|---|
| Ceylon tree-nymph | Idea iasonia | |
| Ceylon tiger | Parantica taprobana | |
| Ceylon palmfly | Elymnias singhala | |
| Ceylon treebrown | Lethe daretis | |
| Ceylon forester | Lethe dynsate | |
| Cingalese bushbrown | Mycalesis rama | |
| Sinhalese five-ring | Ypthima singala | |
| Blue oak leaf | Kallima philarchus | |
| Ormiston's oakblue | Arhopala ormistoni | |
| Ceylon cerulean | Jamides coruscans | |
| Milky cerulean | Jamides lacteata | |
| Woodhouse's four lineblue | Nacaduba ollyetti | |
| Pale Ceylon six lineblue | Nacaduba sinhala | |
| Green's silverline | Cigaritis greeni | |
| Clouded silverline | Cigaritis nubilus | |
| Ceylon indigo royal | Tajuria arida | |
| Ceylon hedge blue | Udara lanka | |
| Lesser albatross | Appias galene | |
| One spot grass yellow | Eurema andersonii | |
| Ceylon rose | Pachliopta jophon | |
| Common birdwing | Troides darsius | |
| Black flat | Celaenorrhinus spilothyrus | |
| Decorated ace | Halpe decorata |