By Our Reporter
SHILLONG, Feb 19: Scientists of the Zoological Survey of India (ZSI) here have prepared, for the first time, a comprehensive report of two-way mass migration of earthworms at Mawlyngot, a remote hamlet under Mawkynrew block in East Khasi Hills district.
A unique blue worm, scientifically identified as Perionyx macintoshi, undertakes annual migration – one uphill in spring and another downhill in autumn – to evade the environmental factors that affect them.
The research was carried out from 2011 to 2015 by ZSI, Shillong, in an area around the Mawlyngot plateau and the rivers – Um Stew and Um Ñiuh – that skirt around it.
“The study on documenting the mass migration of earthworms at Mawlyngot was initiated by Ilona Jacinta Kharkongor after she came across a report about the migration in a local news channel in 2011”, said Bhaskar Saikia, who has co-authored the research findings along with her in the latest issue of the journal, Records of the Zoological Survey of India.
The uphill spring migration starts around April-May each year, coinciding with the onset of monsoon when the earthworms emerge from the rivers and streams where they ‘overwinter’ under the rocks.
Their emergence is probably triggered by the increased flow of water in such rivers and streams signalling the arrival of the rains.
Similarly, the downhill autumn migration starts around September-October when the vegetation begins to dry off and the temperature and humidity drop. Timing is of utmost importance during the downhill autumn migration. Any deviation and the earthworms will fail to reach their favoured destination.
“In October, 2013, we observed hundreds of earthworms, all in a line, having died of desiccation before they could reach the water body down in the gorge. That particular year, the rain stopped abruptly in September-end after a shower that lasted for four to five days,” said Kharkongor.
Previous information on earthworm migration dates back to more than four decades and was more of a chance encounter rather than any regular field observation.
Interestingly, while carrying out their field study, the ZSI team was pleasantly surprised to learn that a top bureaucrat, Barkos Warjri, who was then serving as additional chief secretary to the Meghalaya government, was interested in the mass migration phenomenon unfolding in the remote valley.
“Sir Barkos is a wildlife enthusiast and we were pleasantly surprised to learn that such a high-ranked officer would be joining us in the field, treading jungles and ravines and wading through hill streams,” said Saikia.
“We are also grateful to Bah Nongspung of Mawlyngot, who was always willing to guide us in the field during our quest for these blue worms,” said Kharkongor.
Surrounded by pristine valleys, Mawlyngot is about 45 km from here.
Locals, who were mainly dependent upon broomstick cultivation, have shifted to the cultivation of organic tea, which is marketed under the brand name ‘Urlong’ that is slowly becoming a popular tea brand.
According to Kharkongor, the earthworms of Mawlyngot have a ‘role’ to play in enriching the soil, and hence, supporting the organic revolution unfolding there.