Dragonfly migration

by

Published on SundayTimes on 27.10.2019

The possibility of mass migratoin of dragonflies across Sri Lanka was first published by SundayTimes on 2011. It is believed the same phenomena reported last Sunday.

Not only birds, but dragonflies too are found to be migrating long distances. The sudden increase of dragonflies in some areas of colombo suggest their annual mass migration happened last week.

Sudden influx of dragonflies were best felt by those live in coastal belts as they usually arrive as a wave. The coastal community in near Dehiwala railway station confirms they sudden influx of dragonflies on Sunday 20th of October. “It was around 8.30 or 9 in the night that these creatures start coming. They flew directly into our houses like those winged-termites (meru in sinhala) swarming around” said Chaminda Pushpakumara a resident near Dehiwala Railway station. “We tried to put them out, but it was just futile exercise” others in the community too shared similar experiences.

Sudden increase of Dragonflies were observed in other areas as well. Hemal Pieris who lives in Kynsey road in Borella found one in his upstair bathroom. “I haven’t seen a dragonfly in many years and delighted of seeing one inside my own house. I gently coaxed it to fly away through  the
window” Mr.Peiris said.

Responding to a post on the social media put by the team of MigrantWatch who promote observation of migratory species in Sri Lanka, many responded seeing sudden influx of dragonflies from different areas. Vishwamithra Kadurugamuwa made his observation at Town hall in colombo 7. “I Was actually telling my wife that it must be a dragonfly migration” Mr.Kadurugamuwa who had heard of the phenomena said.

The posibility that a mass migration of dragonflies could be happening across Sri Lanka was first observed in 2011 by Nashath Hafi who is a member of the Field Ornithology Group of Sri Lanka that setup its MigrantWatch program with intention to study the migration phenomena. “I was waiting for the train in Moratuwa railway station in the morning watching some birds at the time I observed wave of dragonflies. Usually the dragonflies flying casually on circular route, but all these were moving southward. Thousands of dragonflies were seen moving across and it was a spectacular scene” Mr.Hafi reminded his rare sight.

Mr.Hafi continued to observe the Southbound dragonflies from Moratuwa to all the way until Kollupitiya. When finding more information, the information about a dragonfly migration. Maldivian-based biologist Dr. Charles Anderson initially revealed about this migration which he suggest be happening across India to Maldives and all the way to Africa based on observations of mass aggravation of dragonflies in different areas. . According to Dr.Anderson’s study, the path dragonfly use has a distance of around 14,000 kilometres and could be called the world’s longest insect migration.

A Globe Skimmer Dragonfly found dehiwala

Dr.Anderson based on his data calculated the Dragonflies first appear in the capital city of Maldives on mean 21st of October on average. Quite interestingly the wave of Dragonflies was observed in Sri Lanka in 2011 was on 20th October. What is more surprising is this year the mass movement of dragonflies were observed on the same day – 20th of October. Dragonfly numbers peak in November and December, before the insects then disappear once more. The insects arrive in waves, with each staying for no more than a few days.

Indian observers also reported large agrevation of Dragonflies on Indian beaches. a dragonfly swarm reported from Mumbai coast on 14th Oct and different parts according to Sujith Chandran who is from Kerala. The migratory dragonflies fly along with the coast is observed in Indian.

According to Mr.Chandran, the communities in Keral coastal areas know this phenomena happened with the onset of Monsoon winds. “The locals believe the dragonflies emerge at time of when sun enters zordiac of Libra. In local language the Zordiac sign Libra is called ‘thula’ and dragonflies are called as ‘thumbi’- so locals call named them as ‘Thula Thumbi’”, said Mr.Chandran.

When interviewed, even the local coastal community – specially the members of the fishing communities live near coast are known of the phenomena, eventhough it is still least studied phenomena that came into light recently.

The species that involve in the migration are called as the globe skimmer or globe wanderer scientifically known as Pantala flavescens. The dragonfly is up to 4.5 cm long, that can have wingspans around 7.5 cm . They are good flier who tirelessly fly for hours without making any perch. The wandering glider flies in large swarms.

Globe skimmer is considered to be the most widespread dragonfly on the planet with good population on every continent except Antartica although rare in Europe according to the literature. According to a research by scientists at Rutgers University-Newark of USA studying the genes of Globe Skimmer found that specimen found from different areas of the world have similar genetic profiles so similar. They studied Pantala flavescens from USA, Canada, Japan, Korea, India, South America and interpret this similarities as a result of long distant migration.

Earlier this week, on the coastal areas observed in Dehiwala, Wellawaththa and Bambalapitiya, swarms of dragonflies consisting of 10 – 15 individuals could be commonly observed, but by the Friday, this number had decreased drastically spotting only few individuals according to the observers. This could indicate either the dragonflies moved away from Sri Lanka to continue their journey toward Maldives or spread inland. Perhaps part of the swarm moves away, while another stays. There are more questions for science to find out and if it could firmly establish, the Dragonfly migration could be yet another spectacular wildlife encounter Sri Lanka could be blessed to witness.

Report increase of dragonflies in your area

Have you seen an increase of dragonflies in your area..? If so, it could possibly be a migratory dragonfly. The MigrantWatch team of the Field Ornithology Group of Sri Lanka (FOGSL) based at University Colombo welcomes your to contribute to their citizen science program to study this phenomena. You can send them your observations through email to migrantwatch.srilanka@gmail.com

Tags:

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s


%d bloggers like this: