When Gamini Mayadunne’s fellow worker Maduwanthi showed him a large winged insect she had caught from her garden in Gampola near the 7th Milepost on the 10th of May, thinking it was a butterfly, he knew this was something special. It had a wingspan of about 8 inches and had been resting on an Anoda - Custard apple tree. An amateur naturalist, Mayadunne – a photographer and the owner of “Upali Studio” in Kadugannawa realized it was no butterfly, but one of the largest moths in Sri Lanka.
Mayadunne got in touch with Tharanga Aluthwattha of Peradeniya University, whose research interest is the Lepidoptera species (butterflies, skippers and moths). The insect was identified as the Indian Moon Moth or Indian Luna Moth (Actias selene), usually a nocturnal creature. The Moon Moth has a very soft colouration of very pale green forewings with white at the base. It has four spots on its wings, perhaps to confuse predators who would love to take the large insect as their meal.
“Despite the bigger size, Moon Moths also have an interesting life cycle,” said Tharanga, who is studying Lankan moths for his postgraduate degree. The Luna Moths don't eat at their last stage when they transform into a winged insect. In fact Moon Moths don't even have a mouth and their sole purpose of living is to mate. The Mature Moon Moths only live for about a week.
“The one we found lived for nine days and laid about 200 eggs for three days,” said Tharanga. These eggs started hatching after another three days giving rise to tiny spiny caterpillars. The caterpillar of the Moon Moth feeds on a common woody plant locally known as ‘Hik’ (Lannea coromandelica).
Tharanga is now rearing caterpillars and studying their interesting life history. The caterpillars too like the winged insect are interesting to watch. They change colour on different larvae stages. According to literature, the Moon Moth Caterpillar goes through five different larvae stages and changes colour from reddish-brown to red to green. Tharanga raises these caterpillars in a small enclosure made especially for the ‘offspring’ of the Moon Moth found in Kadugannawa.
The Luna moth is considered rare and Tharanga recalls his first sighting on a field excursion to Algama Ella while he was still a schoolboy. “The flying insect reminded us of the Paradise Flycatcher (Sudu Redi Hora) with its long tail in flight. But to our surprise it sat on a rock for a while showing its beauty,” Tharanga recalls.
The Moon Moth belongs to the family Saturnidae which has both the largest moth in the world as well as the largest moth in Sri Lanka. The former is the Hercules Moth and the Atlas moth the largest one in Sri Lanka that can grow upto 12 inches.
Tharanga also showed us a photo of the Atlas Moth photographed as recently on January 10, 2010 resting on a parked truck beside the Colombo - Kandy road near Kegalle. He thinks the moths may have been attracted to the headlights or the heat of the engine.
Moths of Sri Lanka
According to past studies conducted before the 1900s, about 1915 different species of moths have been recorded from Sri Lanka. But the studies in the last century have increased the number.
The ongoing revision of Sri Lankan hawk moths by Tharanga has seen the number change from 39 to some 50.
Moths perform an important ecosystem service of pollination. Both Diurnal and Nocturnal moths are important pollinators, but the flowers that bloom at night usually with pale colours/ white and pleasant scent depend on nocturnal moths for pollination. However, the larvae of many micro moths are also considered pests of coconut, paddy, beans, cabbage and some fruit species as well. For example the Paddy leaf roller (“Kola hakulana dalambuwa”) and paddy stem borer (‘Puruk Panuwa’) that have already become a headache for farmers are caterpillars of moths.
Moths can be commonly seen in our gardens too, though often misidentified as butterflies. Moths usually have a thick and fuzzy body compared to the thin smooth body of butterflies. Moths hold their wings flat against their bodies when resting, but butterflies usually held their wings vertically.
The ends of the antennae are thin or often feathery in moths while butterfly antenna ends with rounded clubs.
The Tiger moth is a common and attractive day-flying moth in our gardens. You may also have seen some big green “worm” in Wathusudda bushes.
This is the caterpillar of the Oleander Hawk Moth which has a camouflage suit with a Kfir (aircraft) like body.
If you walk across the grass in your garden you will see some small insects fly off and hide under grass blades or other leaves.
They may possibly be micro moths. Also observe how many different moths are attracted to light in your home, says the Moth expert asking the readers to open their eyes to these least studied creatures.