Sikkim Chief Minister Prem Singh Tamang on the occasion of World Environment Day declared Blue Duke the state butterfly. Blue Duke, which goes by the scientific name Bassarona durga durga, is unique to Sikkim and the eastern Himalayas. It was discovered in the state in 1858.
The idea of a state butterfly was brought by butterfly enthusiast Nosang M Limboo from Darap as part of The Butterfly Society of Sikkim (TPCF) in 2018.
Blue Duke falls in Schedule 2 of the Wildlife Protection Act, 1972 and is a highly protected butterfly species in the Himalayas. Krishna Peacock (Papilio krishna) secured 43 per cent of the votes in the online polls to secure the second position.