19 Jun Hovers Like A Hummingbird, Looks Like A Bee?
The Return Of The Hawk Moth To Mussoorie
If you’ve seen a hawk moth hovering in your backyard and wondered whether it is a bird, don’t berate yourself. This particular moth is also known as the humming bird moth for this very reason. It belongs to the moth Family Sphingidae and is a common sight in gardens. During the first half of the 20th century, around 50 species were recorded from Mussoorie. Let’s find out whether this number has risen.
Peter Smetacek, famed Indian lepidopterist from Bhimtal. Uttarakhand, recently helped us initiate the Hawk Moth project at Woodstock school sponsored by the Hanifl Centre and Winterline Foundation. He is being assisted by Rajashree Bhuyan, who recently completed her Masters in Environmental Science from Assam University, Silchar. You’re sure to see them around, observing and recording moths in our backyard by day and by night, for another few months.
Peter Smetacek’s love for Lepidoptera began as a child in the company of his father, the late Fred Smetacek Sr, also a lepidopterist. The Smetacek family’s collection has more than 2,000 species- all housed in the Butterfly Research Centre, founded recently by Peter. He has researched and published sixty papers on the subject and is credited with discovering three new butterfly taxa, among them Neptis miah varshneyi, which is the first butterfly described by an Indian. He also broke new ground using a lepidoptera community as an indicator of climate change! He has very generously offered to share his expertise on hawkmoths and explains the Hawk Moth project in more detail below.
In 1937, TRD Bell and Lt. Col. FB Scott published a monograph on the Hawkmoths of India as a part of the Fauna of British India series. The extremely thorough work of these two stalwarts resulted in a work so complete that little has been added to it during subsequent years. While Bell worked the Western Ghats around Kanara, Scott scoured the forests around Mussoorie and Shillong for caterpillars and adults.
Scott and others managed to record 62 species of Hawkmoths from the Western Himalaya, compared with 135 species from the Eastern Himalaya and 75 from Southern India.
During the 1970s and 80s, the late Fred Smetacek Sr collected moths in Bhimtal, some 120 miles east of Mussoorie in the Western Himalaya. When these were identified in the late 1980s, it turned out that there were many species that had not been previously recorded from the Western Himalaya. Of the 77 species recorded from Jones Estate, 32 had not been reported from the Western Himalaya by Bell & Scott. Matters got interesting when the East Himalayan species, Marumba cristata, not recorded from Mussoorie by Bell & Scott, was recorded from Shimla, west of Mussoorie, in 1991. This implies that the moth is now found in Mussoorie, suggesting that the moth had moved west during the period after Bell & Scott completed their study. Another ‘Eastern’ species, Theretra griseomarginata, was recently recorded in Dehra Dun.
In 1994, the results of the Bhimtal survey were published as an Occasional Paper (156) by the Zoological Survey of India. It proposed that the new records had moved into the west Himalaya recently, after the study by Bell & Scott. Since vegetation in the West Himalaya had not noticeably changed during the period, the reason for this expansion in range was probably climatic change, wherein soil humidity increased and winters were less severe, enabling tropical and subtropical species to colonise the drier Western Himalaya.
Hawkmoths burrow underground to pupate. In order to survive, they need a certain minimum amount of soil humidity throughout the pupation period, which is usually through the winter months. Drying out of the soil below a critical level for even a few days in the course of a season can wipe out a population of these moths. This is one of the factors restricting the distribution of tropical species along the Himalayan range, so that even if the plant that the caterpillar feeds on is present, the moths will be unable to colonize the area.
However, the nagging doubt remained that the dividing line between the eastern and Western Himalayan fauna lies somewhere between Bhimtal and Mussoorie. This would mean that no change had occurred and the moths were always present in Bhimtal, even when FB Scott’s study was being conducted at Mussoorie.
Since Kumaon, where Bhimtal is situated, was a grey area on the Hawkmoth map, this possibility could not be ruled out. In 1991, I scoured the Hope Entomological Collection at the University Museum in Oxford for specimens from Kumaon, and managed to locate a single specimen taken in Nainital in 1902 among the thousands of Indian Hawkmoths in that collection.
Under the present project, the Hawkmoths of Mussoorie will be surveyed. This will provide data about the current situation and hopefully resolve the question whether the Hawkmoth community in this area has changed since 1937.
If the findings of the Bhimtal survey are borne out, it will confirm that soil humidity regimes have changed during the past 70 years, so that winters do not have a dry period that would normally dry out the pupae of typically Eastern Himalaya species of moths.
The early warning regarding the direction of ongoing climatic change in the Himalaya given by the hawkmoths in 1994 was the first time that a community of insects was (in retrospect) successfully used to assess and predict the direction of climatic change, making this survey a pioneering work on the use of bio-indicators to predict climatic and other changes in the environment. It is hoped that some interesting findings will emerge from the ongoing project in Mussoorie, since reliable base line data is available for the area in the form of Bell & Scott’s publication as well as several butterfly surveys dating from the 1890s onwards.
References:The Hawkmoths of Kumaon, N. India- a probable case of faunal drift. Peter Smetacek, Records of the Zoological Survey of India, Occasional Paper 156
The Fauna of British India including Ceylon and Burmah, Moths Volume 5, Sphingidae, TRD Bell & FB Scott, Taylor & Francis, London.
Read more about Peter’s work:
TEDx Mehrauli: The Butterfly Effect Controls Rivers: http://bit.ly/1nlXoWQ
Watch his presentation on‘Butterflies on the roof of the world’ at Woodstock school. http://youtu.be/K_aOq7GjSwM