Dryas iulia ssp.

The Julia

Koh Samui and Koh Pha Ngan.

This species appears to have become naturalised on on these islands only since 2006 or 2007. The butterfly is found naturally in the southern states of the USA southwards as far as the northern countries of S. America. It was almost certainly an accidental introduction on some imported plants, or the result of an 'accidental' release, as the species is popular, both with Butterfly Farms, and also with the Wedding Butterfly Release programs which have become so prevalent in recent years. However, specimens have been seen on an almost daily basis, and so it is highly likely that they are breeding on the island, but larvae of the species have yet to be seen here to substantiate this, though mating pairs have been seen. There have been occasional reports of other wild specimens from the mainland, but they have always been in close vicinity to a Butterfly Farm that has kept this species. The local Farm has not had this species.

It is not currently known which subspecies (of which there are many in the Americas) this is. There is currently scientific work being undertaken to not only find this out, but also to try and discover the source/s of these Asian specimens.

It is very fond of Lantana flowers, and can be seen, any sunny day feeding on these plants in gardens.

Flight Period



75 - 90mm

Early Stages

Fully known, but not pictured.

Larval Foodplant

Passiflora species, probably including the local Passiflora foetida (Passifloraceae)


Natural range is Southern states of USA down to Northern countries of S. America.

In Thailand it has been seen from the southern borders with Malaysia to Chumphon, and was recently found on Langkawi Island, Malaysia. It is undoubtedly spreading, both north and south.