15 September 2013

Life History of the Great Imperial v2.0

Life History of the Great Imperial (Jacoona anasuja anasuja)
An earlier version of the life history of the Great Imperial can be viewed by clicking this link.

Butterfly Biodata:
Genus: Jacoona Distant, 1884
Species: anasuja
C & R Felder, 1865
Sub-species: anasuja
C & R Felder, 1865
Wingspan of Adult Butterfly: 34-38mm
Caterpillar Local Host Plants:
Dendropthoe pentandra (Loranthaceae), Scurrula ferruginea (Loranthaceae).

A sunbathing  Great Imperial  displaying its upperside.

A male Great Imperial.

Physical Description of Adult Butterfly:
Above, the male is dark brown with lower halves of both wings in shining blue. In the forewing, there is a short and oblique blue band in the apical area, and a black oval band in the outer part of the cell. The female is mainly brown. In its hindwing, the tornal area is white with embedded black spots in space 1b, space 2 and in the tornal lobe. Underneath, both sexes are mainly yellowish orange with the lower half of the hindwing white. Black post-discal striae are present in the tornal half of the hindwing. In the forewing, the basal part of vein 12 is black (this is a key characteristic for distinguishing the Great Imperial from the Grand Imperial). There are tails at the end of veins 1b and 2 in the hindwing. For the tail at end of vein 2, the one for the male is little more than a tooth, while that of the female is moderately long. As for the tail at end of vein 1b, the one for the male is long and sword-like, while that for the female is even longer and fluffy in appearance.

A newly eclosed male Great Imperial resting on its pupal case.

A male Great Imperial taking nectar from Syzygium flowers.

Field Observations of Butterfly Behaviour:
This species is rare in Singapore. The handful of sightings take place mainly in the Central Catchment Reserve, as well as small pockets of wooded area to its west and north. The Great Imperial appears to be a tree-top dweller. The fast flying adults typically perch with its wings closed upright between flights. In sunny weather, however, they have been observed to sun-bathe with wings fully open.