The Story of Finding Callerebia dibangensis: An Interview with Purnendu Roy

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Callerebia dibangensis (Image Courtesy: Purnendu Roy)

A pleasant surprise hit us recently from the lush greenery of Dibang Valley in Arunchal Pradesh, when Purnendu Roy, a naturalist, discovered a new butterfly species Callerebia dibangensis from Mithun Valley, approximately 5 kilometres from Aini. The surprise was double-fold. First- The butterfly was present in the region at least for the last 26 years,(as we know now) but was overlooked so far. Second- Roy was not a full-time scientist, but just a naturalist, with a particular interest in the eastern Himalaya. 

So when we contacted Roy to know more about the story behind this discovery, he responded to us in detail. Here we share our email interview with Purnendu Roy for our readers.

Q. What was the most difficult part in deciding the identity of the new species?

A. The only field guide I had in 1987 was a reprint of Wynter-Blyth "Butterflies of the Indian Region".  Though pretty comprehensive it poorly covered the northeast, the plates were of an extremely poor quality and some of the keys were not sufficient to identify all the species you would come across in the NE.

At the end of my trip in 1987 I had several species of interest which I could not identify. I tried to identify them by checking the literature available at the Zoological library. I had some success in some of the species, but the literature on Callerebia was not very illuminating and very few species were actually illustrated so I reached a dead end trying to identify that specimen.

In April 2012 I assisted Sanjay Sondhi of the Titli Trust(a non-profit nature conservation organisation based in Dehradun) with a biodiversity survey of Pakke, Sessa and Eaglenest in Arunachal Pradesh. At Eaglenest we saw Gonepteryx amintha thibetana which I had previously collected from the Dibang valley in 1987, but never reported. In the preparation of that paper, I took the opportunity to look again at some of the specimens I was not able to identify in 1987.

It was through the assistance of Dr David Lees at the British Natural History Museum, London that some of the species were finally determined, but there was nothing quite like this Callerebia in the NHM collection and it was suggested that I should describe it as a new species.

Not having access to comparison materials is the biggest obstacle for identification and is one of the main reasons why I am strong supporter of open access resources. The more materials we have on open access the easier it will be for naturalists to document and make discoveries.

Q. It appears to have a long gap between collecting the specimen and publishing the study (almost more than 25 years). Why was it so delayed?

A. As I said earlier, I reached a dead end in trying to identify some of the species. I subsequently concentrated on my work in fair trade. In 2012, my partner insisted that I take a sabbatical from work and go back to my interest in butteflies and this led to me to the work of Sanjay Sondhi.

I was a member of the Bombay Natural History society earlier, but I never really made contact with anyone else interested in butterflies in that society. The internet has made it easier now to connect with people and I think this is encouraging a resurgence in Indian butterfly interest and is also enabling me to keep up my interest. 

Q. In the study, you point out that Upper Dibang valley has certain geographical characteristics which increases the endemic nature of the species found here. Does it increase the conservation significance of the place?

A. I think so. In addition the whole of the Dibang river watershed lies within India. It is relatively intact with unbroken stretches of sub-tropical forests to the permanent snow line of the main Himalayan range. I am not sure if there is any comparable region in India.

Q. Is there any specific threat for the species in particular and the other insect diversity in the area?

A. At the elevation it was collected there are no specific threats. The proposed Dibang dam is however a serious threat to the riverine forests at lower elevations as highlighted by the MoEF forest panel which rejected the clearance.

Q. It is interesting to see that the species was overlooked for such a long period. Is it actually pointing out that there could be more unknown species in the area? Do you think there is need for more systematic surveys in these areas?

A. If in a well studied group such as butterflies a new species has been overlooked then I think it does illustrate that more new species especially in the less studied fauna will be discovered. There is certainly a need for more systematic studies so that a greater range of altitudes and seasons are covered.

Q. After the publication of the study, did you get any correspondence from any other part regarding the report of the species?

A. None as yet. Recently though another one of the species I recorded in the Dibang valley has been photographed and an article on that species will be published at a later date.

As I work very much with communities in fair trade. I would very much like to see community and grass roots involvement in any conservation initiatives. I am hope that I do get some correspondence in this respect.

Discovery of Callerebia dibangensis, is a pleasant surprise. However, what Purnendu did, adds to the pleasant part of it. From age immemorial, the knowledge of the biodiversity was vital for survival of the human. So the earlier communities handed over the knowledge through their folk songs, tales and traditional customs. When we started devouring the nature and entrusted the responsibility of studying nature upon university courses and arm chair scientists who hate field trips, we left out that vital knowledge, which will decide the fate of being human. 

It is again the time when we need people’s participation in indexing and conserving biodiversity at local level. Purnendu’s attempt, even after a long delay, is a good sign in that way. Let’s hope it will inspire the umpteen people biodiversity initiatives budding around the country.