Do Moths (MEIRAMBI in MANPURI) commit suicide?

For hundreds of years poets have been imagining a moth flying into the naked candle flame as suicide because of its love for the flame. The romantic song sung by Madhubala in the film Mahal, with Ashok Kumar, says it all: Deepak ka bagair keishe parwana jal raha hei? (How can a moth burn without a flame?)

Moths do not commit suicide, but they do have accidents. Moths have a mechanical and simple set of mental processes. They fly in a straight direction, navigating say, by the light of the moon. This is achieved by keeping the moon light at an angle of say 30 degrees to one of the omantidia of their compound eyes.

Moths are positively phototaxic ie they fly towards light, the opposite of cockroaches, which are negatively phototaxic, meaning they run away from light. The moment you switch the light on they scuttle away fast and disappear.

Some migrating moths use the moon as a primary reference point and could calibrate their flight paths as the earth’s rotation causes the moon to move across the sky. There is evidence to support the theory that migrating moths have an internal geomagnetic compass system to guide them in the right direction.

Moths are more sensitive to some wavelengths of light such as ultraviolet. A white light will attract more moths than a yellow light to whose wavelength moths do not respond.  Lots of insects including moths fly using rays from celestial objects and their nervous system is

programmed to maintain a fixed compass direction, maintaining an acute angle relative to these rays.

Supposing, a moth is flying keeping an acute angle of 40 degrees to the rays of the moon it will never hit the moon, as any student of elementary physics will know that these rays from optical infinity are parallel

A moth flying to a candle flame maintaining the same angle will hit the flame sooner or later because the candle is not at optical infinity. The rays radiate out from the flame like the spokes of a wheel. If it is a flame, it will keep the light at the same angle, start circling and spiralling in. An incandescent flame creates hot air above and the moth will fry and drop dead, even if it is not trapped by the flame.

When a moth encounters a much closer artificial light and uses it for navigation, the angle changes noticeably after only a short distance, in addition to being below the horizon. It instinctively corrects its flight path turning towards the light, causing airborne moths to come plummeting downward, resulting in a spiral path that gets closer and closer to the light source. The moth, therefore, will fly into the flame making a neat logarithmatic spiral.

There may be some truth about romantic Urdu poets who write about ‘relationship’ between shamma and parwana.  A theory has been advanced to explain the attraction malemoths have especially for candles. It is based on olfaction – the process of smelling. There is some evidence that olfaction, might be, in some cases, mediated by detection of infra-red spectra of substances. The spiky infra-red spectra of a candle flame happen to contain a number of emissions lines which coincide with the vibration frequencies of the female moth’s pheromone. The male moth is hereby powerfully attracted to the flame, thinking it to be a female moth. It is hypothetical but romantic. How about the female moths?

Moths have been flying and migrating at night for millennia before the invention of candles and other artificial sources of light, using the light of the moon or stars. Their nervous system has been programmed that way. There are many more moths flying using celestial lights – a technique called transverse orientation, than the few we see, that are accidentally killing themselves in candle flames.

I don’t think anybody knows the Darwinian survival value for moths of burning themselves in flames. We know that every human has ancestors, but not everybody has descendents. But human species survive.  Genes survive in those moths, which do not end up in the flames. These genes replicate new moths. So, they do not become extinct. Genes are immortal.

What is a moth? Moths are very similar to butterflies. A moth is a winged insect. Its size varies from 2 mm to 300 mm across. There are more than 100,000 species all over the world. A silkworm is a moth.

Night blooming flowers like Ratki Rani (Queen of the night), night blooming Jasmine, known as Thabal lei in Manipuri, usually depend on moths or bats for pollination.

The moth starts its life as a fertilised egg, which hatches into a larva, which is a wingless worm-like insect known as a caterpillar. Generally, the larvae eat leaves, roots and stems, or fabric made from cotton or wool.

They are voracious eaters collecting a lot of energy for cocooning, destroying agriculture and even forests. When I was a small boy before WW II, I remember my mother feeding caterpillars on mulberry leaves in a basket and how fast they could nibble away at a large leaf.

Before the War my father used to grow cauliflowers and cabbages in our garden. In summer every year, our veranda was full of these creepy black caterpillars that caused me to itch all over. This, I know now is because moth caterpillars have sharp hairs containing toxins. These can be blown into contact with people causing skin rashes with an intense itch. It can also cause itchy eyes and asthma in some people.

The larva of the moth then forms a cocoon around itself by spewing out threads from two salivary glands through tiny holes in their jaws. These threads are continuous. The stage is known as pupa in which it metamorphoses into a winged adult that emerges after a time that varies from moth to moth

Manipur is the home of silkworms with its indigenous mulberry trees- not brought from China as is often rumoured. This is because of the absence of written records in Manipur. It is bad enough to believe histories let alone oral traditions. History depends on who is writing it and for whom.

Silk was apparently used in ancient China 2,500 BCE. The silk making process was smuggled to India about 400 CE. Silk clothes were used in Manipur long before that.

There are thousands of varieties of moth. The Manipuri moth species is quite different. The mulberry trees are of a different variety, perhaps like those in Bengal.

The first country to apply scientific techniques to raising silkworms was Japan, which produces some of the world’s finest silk fabrics. Some Japanese studied the DNA of Japanese moths belonging to the family Micropterogdae that fed on liverworts Cynocephalus conium. They compared the moths’ DNA and constructed a family tree. They found some 25 distinct species of moth, which had diverged from a common ancestor between 35 and 15 million years ago.

Anyone who touches the wings of a butterfly, or a moth finds that something like dust comes off on his fingers. The dust is made up of tiny scales. The scales grow in rows and give the wings their patterns of colours. The scales also account for the scientific name for butterflies and moths. Together they are called Lepidoptera, which means “scaly winged”.

I remember seeing my mother rearing silkworms in baskets (cottage sericulture). The silk threads were unbound from the cocoons after immersing them in hot water, which dissolves the ceresin (gum) and kills the pupae.

The life span of a moth varies from only a few days to several months. Adult moths usually live near the plant on which their larvae feed. The silk moth is the only domesticated moth and is not found in the wild though it is recorded that the worms and mulberry trees were wild in ancient China.

Moths differ from butterflies. An adult moth typically has feathery antennae, is active at night and rests with its wings held horizontally. Adult butterflies usually have knobbly or hooked antennae and are active during the day. They hold their wings vertically when at rest.

Recently Dutch researchers found from a database of over 3.5 million records that the population of moths is declining because moths are not attracted to artificial light. With the result a few moths have begun to evolve to become less sensitive to light.

Let me end the mystery of moth’s flight with a religious symbolism of moth with two lines from the 20th century Sufi Master Hazarat Inayat Khan.

Moth: I gave you, my life.

Flame: I allowed you to kiss me.

Dr IM Singh

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