There are two populations of the Ceylon Tree Nymph.

The main threat faced by the Ceylon Tree Nymph is the destruction of its habitat.

The early stages of life of the Ceylon Tree Nymph are not well recorded.

Ceylon Tree Nymphs from the dry zone of the country are usually larger in size and lighter in colour than ones from the wet zone.

In the IUCN red list, the Ceylon Tree Nymph is listed as lower Risk/near threatened.

First described by John Westwood in 1848, the Ceylon Tree Nymph can be found in both wet and dry zones of Sri Lanka.

The Ceylon Tree Nymph or Ceylon Tree-nymph (Idea iasonia) is a species of nymphalid butterfly in the Danainae subfamily.

Since the Ceylon Tree Nymph requires very little effort to fly its wing beats are very slow, so slow that the individual movements of each wing can be easily observed.

The surface area of The Ceylon Tree Nymph's wings is relatively large when compared with its weight; this allows it to fly with little effort and stay aloft for long periods of time.

Its binomial name is Idea iasonia.

The Ceylon Tree Nymph or Ceylon Tree-nymph (Idea iasonia) is a species of nymphalid butterfly in the Danainae subfamily.