| Kingdom | Animalia |
|---|---|
| Phylum | Arthropoda |
| Class | Insecta |
| Order | Lepidoptera |
| Family | Danaidae |
| Genus | Idea (1) |
| Size | Wingspan: 110 - 155 mm (2) |
The Ceylon tree nymph is classified as Near Threatened (NT) by the IUCN Red List (1).
The Ceylon tree nymph (Idea iasonia) is a beautiful silvery white butterfly (2) and is the largest member of the Danaidae family in Sri Lanka (3). Both wings are a translucent silvery white, and the forewings are almost twice as long as they are wide (3). The sexes are similar, although females tend to be larger in size (2) and males have narrower wings (3). Individuals from the dry zone tend to be larger and lighter in colour than those from the wet zone, and some individuals may have a reddish hue over the wing surface (3). The fact that the surface area of the wings is very large relative to the weight of this butterfly allows it to fly with the greatest of ease. It can stay aloft for very long periods of time (2), with such slow, effortless wing beats that the sequence of wing movements is easy to observe (3).
The Ceylon tree nymph is found in wet evergreen forests, where it spends most of its time high in the tree canopy. Some colonies are also found in tall forests beside rivers in the dry zone (3).
Although the Ceylon tree nymph spends much of its time flying leisurely high in the tree canopy, it does descend to the ground to feed on nectar and to breed (3). During courtship, males and females fly together for a long period and the male extends two brush-like organs (known as hair pencils) from the tip of his abdomen. These hair pencils brush against the female’s antennae and release pheromones and other chemicals that stimulate her to mate (4). One of these chemicals, danaidone, is poisonous, and is also passed to the female with the sperm during mating. This substance is gathered by the adult males from various plants and deters predators from eating the butterflies. Some of the danaidone passed to the female from the male during mating ends up in the tissues of the female and in her eggs, protecting both the female and the eggs from predation (4).
The main threats facing the beautiful Ceylon tree nymph are destruction and degradation of its habitats (5).
Find out more on the Ceylon tree nymph:
Authenticated (04/04/05) by Gehan de Silva Wijeyeratne of Jetwing Eco Holidays.
http://www.jetwingeco.com/
New images of the Endangered Angel’s Madagascar frog. More
© Gehan de Silva Wijeyeratne
Gehan de Silva Wijeyeratne
155 Model Farm Road
Colombo 8
Sri Lanka
gehan@jetwing.lk
http://www.jetwingeco.com
Embed this ARKive thumbnail link by copying and pasting the code below.
Terms of Use - The displayed thumbnail may be used as a link from your website to ARKive's online content for private, scientific, conservation or educational purposes only. Portlets may NOT be used within Apps.

MyARKive offers the scrapbook feature to signed-up members, allowing you to organize your favourite ARKive images and videos and share them with friends.