Bhutan Is The First Country To Record The Life Cycle Of Ludlow’s Bhutan Glory Successfully
Over 367 days, Tshering Dendup closely observed the metamorphosis of the national butterfly, recording each change in the physical appearance of the species.
By Younten Tshedup | Kuensel
Bhutan’s national butterfly, Ludlow’s Bhutan Glory (Bhutanitis ludlowi), has its life cycle recorded for the first time in its natural habitat of Bumdeling in Trashiyangtse.
The Senior Forestry Officer with the Bumdeling Wildlife Sanctuary (BWS) in Trashiyangtse, Tshering Dendup, released an adult Ludlow’s Bhutan Glory into the wild after recording the complete life cycle of the butterfly on August 21, 2017.
How the life cycle of Ludlow’s Bhutan Glory was successfully recorded
The researcher introduced the freshly laid eggs collected from its natural habitat in Rigsum Goenpa into an ex-situ environment, a greenhouse constructed at the BWS.
Photo: Travel Triangle
He then created a thriving environment artificially through the establishment of the Aristolochia (its novel host plant) nursery inside the greenhouse.
“The present study, the first of its kind in Bhutan and in the world, demystifies and elucidates the complete life cycle of the Bhutanitis ludlowi on its novel larval host plant, Aristochiaceae.”
Usually, the butterflies in the valley are distributed sporadically at an altitude range of 2,200 to 2,500 metres above sea level (masl). The eggs were however, incubated in the ex-situ environment that has been created at an elevation of 1,752 masl.
Over the next 367 days, Tshering Dendup closely observed the metamorphosis of the national butterfly, recording each change in the physical appearance of the species.
He said that the mean total duration of the stage from ‘egg-laying to hatching’ was 18 days of incubation in an ex-situ environment inside the greenhouse.
“Soon after the emergence from the egg, the larva consumes its eggshell before it spreads to feed on young tender leaves of the host plant.”
The larva then passes through eight larval instar stages and a pupal stage before emerging as an adult butterfly over an incredible period of 367 days.
“Probably, this is one of the longest life cycle period for a butterfly.”
The stages between the molts are known as ‘instars’. A young caterpillar that first hatches from its egg is referred to as the first instar caterpillar and the caterpillar’s first molt is known as the second instar.
The life cycle of the Ludlow’s Bhutan Glory is completed in 367 days in three stages:
- egg hatching (14-18 days),
- larva (five months and eight days) and
- pupa (six months and seven days).
After 188 days, the adult butterfly emerges from the chrysalis.
Tshering Dendup said that it was an emotional day when he finally went to release the adult butterfly back into its natural habitat in Rigsum Goenpa.
“For more than a year, I have been closely nurturing and watching it grow through the instars. You develop a bond with it and when you finally let an adult butterfly flutter off into nature, it is an emotional moment.”
More details about the Ludlow’s Bhutan Glory
Brightly coloured, the adult male has a wingspan of about 58.2mm to 60.3mm. The female is usually larger with a wingspan of about 61.02mm to 63.0mm.
Ludlow’s Bhutan Glory was officially endorsed as the national butterfly in 2012 during the 123rd sitting of the Cabinet.
Listed as vulnerable under the International Union for Conservation of Nature (IUCN), not much was known about the butterfly species until now.
The butterfly was first discovered by plant hunters, Frank Ludlow and George Sheriff at Tobrang, the upper parts of Trashiyangtse valley in 1933-34.
Endemic to the Bumdeling valley in Bhutan, Ludlow’s Bhutan Glory was rediscovered after 75 years in 2009 by a Bhutanese forester, Karma Wangdi.
Tshering Dendup said that except for some limited information on the species description, none of the reports really described the complete details of its life cycle in stages.
A joint research team of Bhutanese from the Agriculture and Forest Ministry and Japanese lepidopterists from the Butterfly Society of Japan are the only team which has made references to the early stages of the life cycle of the species.
The team compared the Bhutanitis ludlowi’s morphological characteristics to that of the Bhutanitis lidderdalii Atkinson (Bhutan Glory), till the second instar of its early immature larval stage and adults.
“Apart from this study, no complete study on its life cycle has been conducted,” Tshering Dendup said.
Along with the life cycle of the butterfly, the researcher also observed the defence mechanism of the species from its natural predators and collected more details about its host plant.
Although there has been no research conducted on the number of the butterflies in the area, the Ludlow’s Bhutan Glory has a high mortality rate and a majority of them were not able to turn into adults even from a few hundred eggs hatched.
“We had made attempts for studies in its natural habitat in the past but we could not succeed since the study locations were far away from the head office,” he said.
The lack of awareness among the local communities has also attributed to the failure as the research sites were found destroyed and observation plot trees cut down along with the larvae and host plants.
Given the vulnerable status of the butterfly, an awareness programme and support groups will be formed in the community, with help from the BWS in future. An enrichment plantation of the host plants will also be carried out.
This article first appeared in kuensel and has been edited for Daily Bhutan.