The air is tepid, almost syrupy, laden with the heaviness of old trees breathing. It has the odour of dank mud, decaying wood and things growing. There is something primal, vital about the rainforest that will not leave your nostrils.
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Forests can be unnervingly silent. Not so today, at Assam’s Dihing Patkai National Park. The gloom is permeated with the cacophony of buzzing cicadas, croaking frogs, screaming hornbills, scurrying mammals, breaking twigs, whispering wings, and the drum of ants’ feet marching through leaf litter. Even the trees throb with sound if you put your ears to their bole. And behind it all, the steady patter of an incessant drizzle. The noise spirals upward, dashes against the impenetrable canopy and tumbles back to earth.
The towering trunks and massive buttressed roots make me feel fleeting, inconsequential. There are things to learn here. We think of trees as rooted beings but they travel, sometimes far from where they were born. Some live forever. They can eat light, for god’s sake!
Built of light
But even here are patches of open clearings of silent grass and ponds. Here, light surges in and something otherworldly reveals itself. Floating, wings outstretched, in a rain-dotted pond is a great hornbill. Its massive yellow casque and bill like an overturned country boat. And riding on a fallen giant, gently sipping its life juices, is a silent swarm of exquisite vampires: butterflies.
We tend to think of butterflies as ethereal creatures built of light. Cultural symbols of everything from grace and love to inspirational transformation. Capable of no harm, and feeding on just that purest of foods, nectar. But they have a dark side that we do not often comprehend. A side that would not make it to children’s colouring books.
Blood, sweat and tears
Think of it. If concentrated sugar water was all you drank, wouldn’t you be short of the multitude of chemicals needed to keep a life running? And their only form of intake is sipping moisture through a long proboscis.
So, butterflies actively seek out moist surfaces rich in salts, sugar, sodium and amino acids: wet mud, rotting fruits, dead animals, excrement, and even blood, sweat, and tears. A behaviour commonly called puddling. In fact, they are most partial to urine on moist mud. They totter around unsteadily because they are selecting an ideal spot: a butterfly has its taste receptors on its feet. Alcohols are also imbibed from rotting fruit. They might be flying around drunk for all we know.
In wet forests, mixed flocks can be seen on wet patches of earth or near stream beds. They are also often the first to arrive on corpses. There are some species that have evolved to feed on the juices of decomposing animals with special adaptations to detect carrion from surprisingly long distances. Literally, eaters of the dead, like vultures.
If you look closely enough, you will also notice that the critters release small jets of clear liquid regularly while feeding. Their digestive systems are tiny and process the fluids rapidly, so the poo (mostly pure water) has to be removed continuously to keep them light enough for flight. So the next time a butterfly alights on you and not the person next to you, remember that you are not the Chosen One. You just sweat more and are smellier. It is tasting you.
Butterflies can be aggressive with each other. It is common to see males chasing females and being rebuffed. One species may drive another off a tasty bloom, even engaging in wing-buffeting dog fights. Those powdery delicate wings are serious weapons in such contests.
Many are toxic as an evolutionary mechanism, usually because they feed on toxic plants. Like those in the family Danaine, that are closely associated with toxic milkweed plants. Most milkweed butterflies, like the tigers, are gaudily coloured, advertising their toxicity. And there are others, non-toxic, who mimic them for protection.
It has only recently been revealed to science that some male milkweed butterflies will attack caterpillars of other milkweed species to obtain supplementary chemicals, crucial pheromones that help attract females. The butterflies attack and scratch the toxic caterpillars with claws on their feet and drink their juices. A new term ‘kleptopharmacology’ was coined to explain this behaviour. They have been observed feeding on dead, injured and live caterpillars. It is not yet clear whether these attacks are fatal for caterpillars. Would that make them not just thieves, but possibly murderers and cannibals?
Wings down in Delhi
On the topic of heinous crimes by badly-behaved males, the zebra longwings of southern U.S. are notorious. They are toxic, their caterpillars are cannibalistic and that is not even their worst trait. The pupa is the stage when the butterfly is in its chrysalis, somewhere between caterpillar and adult. When a female zebra longwing is nearly ready to exit her chrysalis, the pupa is set upon by a swarm of jostling over-eager males. The strongest often rips in to the chrysalis with his claws and mates with the yet to emerge female. Scientists often magnanimously call this pupal mating, but there are far worse words we know to name such behaviour.
How does a caterpillar turn into a butterfly? It eats and eats and keeps growing until one day it stops. It finds itself a safe, quiet spot to hang out and then packs itself into a silken blanket and a firmer chrysalis shroud. And then, everything goes quiet.
What happens inside is akin to death. The caterpillars shrivel; their insides dissolve into a liquid mush. Most of their cells die. But some adult cells survive. And voila, we have a brilliant adult butterfly.
Does the butterfly remember the caterpillar since most of the ‘caterpillar cells’ dissolved?
We stop for a coral red snake’s tail sticking out of a bush. Probably dropped by a crested serpent eagle that whooshed by. Dead, slightly bruised. And butterflies are beginning to gather like elegant undertakers that have come to usher the creature’s soul away to the other world.
The author is a writer and birder based in Guwahati.
Watch | The surprising feeding habits of butterflies on magazine.thehindu.com