Environment

Naturalist Yuvan Aves discusses ecology and the threat faced by moths

Iridescent Emerald

Iridescent Emerald   | Photo Credit: M Yuvan

Oak Emerald is its name; this elusive moth, which is confined to the high altitute Oak forests of the Northeast, looks irresistible in parrot green. Then there is Beautiful Cyana; its white body amplified by a splash of red, yellow and brown-coloured patterns, but nothing like The Lesser Golden Emperor which is just a burst of yellow and purple colours all over.

These images posted by naturalist Yuvan Aves on Instagram, as part of National Moth week that is observed in the last week of July, celebrates the beauty of moths. “These are some of the extraordinary moths that are endemic to the Northeast. I photographed these in the forests of Arunachal Pradesh, Sikkim, Assam and West Bengal,” recalls Yuvan, an active member of Madras Naturalists Society.

Beautiful Cyana

Beautiful Cyana   | Photo Credit: M Yuvan

Moth watching, or mothing, is all about waiting, he adds. As moths are attracted to ultraviolet light, one has to put a white sheet lit by mercury vapour lamp and wait for the moths to settle on the screen before photographing them.“You have to stay up all night. In Assam, I set up an alarm for every one hour till 3 am. You have to worry about predators too — lizards, praying mantis, wasps, and cats that always eat the pretty looking moths. If you are in a forest, even owls come and pull the sheets,” says Yuvan.

These endemic moths are also at risk of being wiped out due to human interventions that create adverse habitat. “Moths in the northeast have specific climatic and host plant necessities. If one specific tree is felled, or if there are other changes to its habitat, then the moths are wiped off,” he adds.

Yuvan Aves

Yuvan Aves   | Photo Credit: Special Arrangement

Diverse caterpillars
  • A bagworm moth caterpillar collects dry leaves and twigs and glues them around itself to make a nice little home. Now as there is less vegetation, it has improvised the home with hair, threads and newspapers!
  • If you disturb a Teak Defoliator while feeding on teak leaves, it retaliates and spits out a black gooey secretion
  • Castor semi-looper feeds on castor plants, stores resin in the body and becomes poisonous to predators. It has two little tusks next to its mouth which it uses as a defence mechanism to poke on predators.

Reminiscing of nights spent mothing in the northeast, he says, “I was thrilled to see the Oak Emerald visit our moth-sheet at Lama camp in the Eaglenest Wildlife Sanctuary. It is among the remotest places in the Northeastern hills of India. The Cyana is a small moth that feeds on mosses and has beautiful spots. Yuvan, who photographed the Iridescent Emerald (named for its opalescence) at Neora Valley in West Bengal, says the moth’s body reflects different colours as we move away from it. “Sometimes we are amazed by the beauty... like the Lesser Golden Emperor.”

Lesser Golden Emperor

Lesser Golden Emperor   | Photo Credit: M Yuvan

‘Insect Armageddon’

He mentions the Oleander hawk-moth that he had spotted in Thirukazhukundram, near Chennai. “People call it pillayar poochi because the moth resembles Lord Ganesha’s face. The caterpillar of this moth feeds on arali flowers, stores poison in the body and exhibits an interesting behaviour. It is long, green and also has a hidden pair of eyes. When disturbed, it rolls those big blue eyes like its telling you ‘Hey! I am poisonous. Stay away’,” he says. Another moth that can be spotted in urban areas is the Owlet moth. “It has owl-like eyes on its back, and sits on rock crevices and tree barks. Its eyes are prominent and scares away predators,” he adds. There is also the Fruit-piercing moth, which when disturbed reveals a yellow colour on its hindwings with two black spots resembling watchful eyes.

Oleander Hawkmoth

Oleander Hawkmoth   | Photo Credit: M Yuvan

Yuvan, who recently finished recording 200 species of moths as a part of year long study at Adyar Poonga , says that much of moth ecology remains unknown. “Moths are less studied. We have 15,000 species of moths in India. They are largely nocturnal and difficult to study though insects, moths, flies and bees are the only available pollinators. What is happening now is an Armageddon where we are losing insects at an alarming rate because of air and water pollution, and pesticide use. It threatens our food security. When there is no pollination, we may not get our fruits and vegetables,” he adds.

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Printable version | Oct 1, 2020 7:32:42 AM | https://www.thehindu.com/sci-tech/energy-and-environment/naturalist-yuvan-aves-shares-pictures-to-mark-national-moth-week/article32259451.ece

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