The mesmerising world of moths

Last Updated : 27 July 2018, 19:04 IST

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If you were to take a stroll on a calm night, you are sure to observe small flying insects going in circles under the street lights. With wings like a butterfly albeit not as colourful, these moths flutter around a light source. Their camouflaged beauty, life cycle and diversity are fascinating.

Most moths come alive after sunset when they venture out looking for a sumptuous meal or a mate. While some look to sip the nectar from flowers, others feed on rotting matter. A few never eat as they do not have a mouth! With a very short lifespan as adult moths, they mate, lay eggs and perish. Also, not all moths are nocturnal, or dull and colourless. Crowned the ‘most beautiful insect in the world’, the Madagascan sunset moth (Chrysiridia rhipheus) is a day-flying moth with wings as vivid and colourful as that of a butterfly’s.

Moths are close relatives of butterflies, and both belong to the order Lepidoptera. They have the same stages of a life cycle — eggs, larvae or caterpillars, pupa or chrysalis, and the adults. While butterflies are active mostly during the day, moths prefer the nights. A look at their antennae can help distinguish the two; the antenna of the butterfly is thin and shaped like a club, whereas moths have a hairy, thread-like antenna.

Entomologists estimate that there are about 1,50,000 species of moths all over the world — almost 10 times the number of butterflies. There could be many more waiting to be discovered. “Moths are very diverse, and we have around 120 families all over the world,” says Dr P R Shashank, scientist at the Division of Entomology, ICAR-Indian Agricultural Research Institute and a team member of Moths of India.

In the Indian subcontinent, there are about 15,000 species, belonging to over 84 families. Many of them are recorded in the Eastern Himalayas, particularly along the Myanmar border. Scientists estimate that about 6,000 to 7,000 moth species could be found here alone! Besides, areas like the Western Himalaya and the Northeast are also rich in moths. Scientists hope to find many more in the arid and wastelands, and forest covers across India.

Pollinators, pests and products

Moths play a vital role as the indicators of our ecosystem. “They are an important component of the food chain as they support a range of predators and parasites. They also help in the pollination of many plant species,” says Dr Shashank. Their hairy bodies help them pick up the pollen from flowers they land on and carry it far away. In fact, some moth-pollinated flowers, like the yucca (a native plant in the US) have fragrant white flowers to help the moths spot them in the dark.

The caterpillars of many moths are infamous as agricultural pests. Since they are voracious eaters, they chew up the leaves of plants, bore plant parts and also invade stored food. Many moth species, like the Cotton bollworm (Helicoverpa armigera) are ranked among the top 20 pests of the world. The Indianmeal moth is a frequent invader in our pantries.

Some moths, like the silk moth (Bombyx mori), are reared for their commercial value. Silk extracted from the cocoon of the silkworm pupa is used in textiles, as medicine, a biomaterial, and in the furniture industry. In some parts of the world, moths are a significant food source for people, too. People in some African countries eat moth and butterfly caterpillars, which are rich in protein and healthy fats. They also contain ample quantity of vital minerals, such as potassium, calcium, zinc and iron.

Of late, moths and butterflies are facing many threats to their survival because of change in their habitats as more land is lost to buildings, ploughing up of meadowland, cutting down of hedges, use of insecticides and herbicides, and industrialisation. Besides, trade in moth and butterfly specimens is a flourishing business that has endangered many species. Studies estimate that butterflies and moths are becoming scarcer by about 30-40% in the Eastern Himalayas. Since there is a massive dearth of scholarly knowledge about moths, these estimates are only crude.

“We are still in the preliminary stage of insect conservation. Only butterflies have marked their occurrence with their beauty in the rulebook of Forest Departments,” remarks Dr Shashank. An article reviewing the work on Lepidoptera in India says that Indians have described less than 50 taxa from the Himalayas — a pitiably small number compared to the 700 described by international researchers from the same area. Between 1990 and 2010, a dozen new Hawk moth species were added to the Indian fauna but none by Indians. “In India, just about 40 researchers are working on the taxonomy and identification of moths. In the field of smaller moths (microlepidoptera), which comprises around 50 families, the number drops to just five,” he adds.

Conservation efforts

On the brighter side of things, there are initiatives to conserve these winged beauties. For example, the Titli Trust, a not-for-profit organisation based in Dehradun, works with local communities to incentivise conservation. “To this end, we promote less-fauna linked nature tourism in numerous landscapes in the Himalayas,” says Sanjay Sondhi, a naturalist and the founder-trustee. As part of the National Moth Week, the trust organises many programmes in association with Doon Nature Walks, Uttarakhand Forest Department and others, every year.

The organisation also conducts community-led nature tours to Pakke Tiger Reserve, Eaglenest Wildlife Sanctuary and Garo Hills in Northeast India, and Pawalgarh Conservation Reserve, Devalsari and Naina Devi Wildlife Sanctuary in the Western Himalayas. “In all these locations, butterfly and moth tourism are, to some extent, supporting local communities to earn a nature-linked livelihood. These efforts have also created awareness about moths, and their role in the ecosystem,” shares Sondhi.

Moths of India is a peer-reviewed website devoted to Indian moths that has comprehensive information on their natural history and biology. It aims to gather population and distributional data and spread awareness about the conservation of moths. Also a citizen science initiative, it facilitates those interested to contribute moth pictures, spot records or other articles related to Indian moths.

Although moths have a long way to go before they make their mark, what better opportunity than now to be a ‘moth’er! With the National Moth Week currently underway, here is your opportunity to kindle some liking towards these nocturnal beauties.

Published 27 July 2018, 18:40 IST

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