The Sri Lanka Emerald Spredwing (Sinhalestes orientalis) is among the most remarkable odonate discoveries in South Asia. As the only member of its genus, Sinhalestes, it occupies a singular position in the global record of damselflies — a living relic found nowhere else on earth. First described in 1859, it subsequently vanished from scientific records for well over a century, leading many entomologists to fear it had been lost entirely.
What makes the Sri Lanka Emerald Spredwing so unusual?
Its monotypic genus status sets it apart immediately. Most damselfly genera contain multiple species distributed across a region, but Sinhalestes has exactly one known member, found exclusively in Sri Lanka. This makes every individual sighting scientifically significant. The species belongs to the family Lestidae — the spreadwings — whose members are recognised by their habit of resting with wings held partially open, at an angle away from the body, rather than folded flat along the abdomen as most damselflies do.
Its iridescent emerald coloration, visible under direct light along forest streams, is the feature that gives the species its common name. In Sinhala it is known as ඉන්ද්රනීල විවරතටු ඉරටුකූරා, a name that reflects both its coloration and its spreadwing posture.
Where is the Sri Lanka Emerald Spredwing found?
After its long absence from the record, the species was rediscovered in the Samanala Adaviya mountain range in the central highlands. It is restricted to dense, close-canopy forest at elevations typically above 900 metres, where the forest floor remains cool and humid and large streams run through largely undisturbed vegetation.
Even within this habitat, encounters are infrequent. The combination of a narrow altitudinal range, strict canopy requirements, and what appears to be naturally low population density makes finding one a matter of patience and some luck. Researchers and wildlife photographers who visit the highlands specifically for odonates may spend several days in suitable habitat before obtaining a confirmed sighting.
The montane forests of the central highlands that shelter this species share ecological characteristics with the Horton Plains National Park biome — high elevation, persistent cloud moisture, and a closed canopy that filters direct sunlight to the forest floor. While the species has not been confirmed inside Horton Plains itself, the broader highland belt represents its core range.
What behaviour has been observed in the wild?
Field observations are limited by the species' rarity, but the documented behaviour of males follows a pattern common among stream-associated lestids. Males perch on vegetation roughly two metres above the ground, choosing positions close to sunlit patches along larger streams — likely a territorial display or mate-search strategy. They tend to return to the same perch repeatedly, which gives patient observers a better chance of a prolonged view once an individual is located.
Females have been recorded far less frequently than males. This is not unusual among odonates — females of many species spend the majority of their time away from water, visiting streams only briefly to mate and oviposit. As a result, their micro-habitat preferences, flight period, and oviposition sites remain poorly documented for this species.
Immature individuals (tenerals) and larval stages have received even less study, largely because the cryptic stream-bed habitats of montane Sri Lanka are difficult to survey systematically.
Why is conservation of this species a priority?
The IUCN and Sri Lankan conservation authorities regard the species as a high priority for protection, for several overlapping reasons. Its monotypic genus status means that losing this species would erase an entire evolutionary lineage with no close relative to fill the gap. Its restricted range — confined to a narrow band of highland forest — means that any significant degradation of that habitat could be catastrophic at the population level.
Threats facing the species and its habitat include encroachment at forest edges, changes in water quality in montane streams, and the longer-term effects of climate variability on cloud-forest moisture regimes. The Sinharaja Forest Reserve, while lower in elevation, offers a useful parallel: a protected forest where strict access management has preserved conditions for endemic species that would otherwise face pressure from surrounding land use.
Sri Lanka has one of the highest rates of odonate endemism in the world relative to its land area, and the Emerald Spredwing is a flagship for that broader conservation story. Protecting the montane stream corridors where it lives also benefits dozens of other endemic invertebrates, amphibians, and birds that share the same habitat requirements.
How can wildlife enthusiasts responsibly seek out this species?
For naturalists with a specific interest in Sri Lanka's endemic odonates, a few practical considerations apply. The central highlands are best approached during the inter-monsoon periods — typically March to April and again from August into early October — when stream levels are moderate and forest paths are accessible without being waterlogged.
Working with a local guide who knows the highland forest trails is strongly advisable. Beyond improving the chances of a sighting, a knowledgeable guide ensures that stream banks and riparian vegetation are not disturbed during the visit. The fragility of montane stream habitats means that well-intentioned observers can inadvertently damage the microhabitats they have come to see.
Photography of odonates at close range is best done with a macro lens and without flash where possible, as repeated flash exposure near a perched individual can alter its behaviour. Keeping a respectful distance and using a longer focal length achieves equivalent results with less disturbance.
What other endemic wildlife shares the Emerald Spredwing's highland habitat?
The montane forests of central Sri Lanka support an exceptional concentration of endemism across multiple taxa. Fellow odonate enthusiasts visiting the region for the Emerald Spredwing are likely to encounter several other damselflies and dragonflies found nowhere else. The same stream corridors are home to endemic fish species, including several members of the genus Puntius, and the riparian zones shelter endemic amphibians such as shrub frogs of the genus Pseudophilautus.
Bird species characteristic of the Sri Lankan highlands — including the Sri Lanka whistling thrush, Sri Lanka wood pigeon, and Ceylon hill myna — are regularly recorded in the same forest tracts. For any naturalist spending time in the highlands for odonates, the broader biodiversity rewards are considerable.
