The Royal Assyrian (Terinos terpander robertsia)
The Royal Assyrian belongs to the butterfly sub-family Heliconiinae of the family Nymphalidae. The genus Terinos features medium sized butterflies with angled wings. Of the three species found in Malaysia and Singapore, only the Royal Assyrian is known to exist in Singapore. All three species are rich purple above with white or pale orange area on the hindwings.
The Royal Assyrian is not uncommon in Singapore, and can be found in the nature reserves where its host plant, Rinorea anguifera (Violaceae) grows. Seasonally, several individuals are encountered together in the vicinity of its host plant. The species is most often seen along MacRitchie Nature Trail and on the fringes of some of the reservoir parks.
Males are sometimes observed puddling along damp paths in the forests. A peculiar behaviour of the species is that some individuals, when disturbed, fly and stop on the undersides of leaves with their wings folded shut. The Royal Assyrian is not a particularly strong flyer, but flits from leaf to leaf in the shaded understorey of the forested areas. When alarmed, however, it takes off quite quickly to the treetops.
In the early morning hours, they can be observed to open their wings flat to sunbathe, displaying the attractive rich purple colours of the uppersides of the wings. The spectacular purple upperside of the wings are a sight to behold and is quite unlike any other butterfly species in Singapore. 
Text by Khew SK : Photos by Federick Ho, Tan BJ, Horace Tan, Bob Cheong, LC Goh and Khew SK
