How hawkmoths and Rangoon creepers are eternally attracted to each other

October 13, 2019

The magical association of hawkmoths and Ragoon Creepers

How hawkmoths and Rangoon creepers are eternally attracted to each other

These days in Lahore our homes and gardens are full of insects, nematodes and reptiles. In other words, all around us are insects, worms, frogs and the like. This basically means it is squirming with creepy crawlies. Here is a tale of just one of the myriad of creatures.

As these soft, humid evenings come to a close, our twenty-year old Rangoon creeper or Pachranga Bael (Quisqualis indica) festoons its blooming branches in front of our bedroom windows. All over warmer Pakistan, this climbing plant is loved for its graduated white to pink to dark pink clusters of tubular flowers held all in one gorgeous, scented bunch. Glowing like tiny, flickering ghosts are a whole host of night flying insects around its scented blooms, most intriguing among which is the hawkmoth. Its Latin name is Macroglossum, meaning the long-tongued species of the insect tribe called Sphingini or the sphinx-like ones.

The hawkmoths of Lahore cannot be fathomed without their natural complement, the Rangoon creeper. It is a dance of two inseparable beings that thousands of Lahoris pass by on their evening walks. I wonder if we notice the magic that is going on over our very heads!

To begin with the hawkmoth, let us go back to the year 1867 and Alfred Russel Wallace, a famed naturalist of England. In those days of colonial explorations, he received a box of dried Orchid flowers from the island of Madagascar. This flower featured something very unusual. In order to reach and eat the sugary nectar at the base of the orchid, a creature with a tongue over 7 inches long would be needed. Of course, in nature, sugar cries out to be eaten by everyone, as we know from our love of honey or dates. Wallace predicted that a hawkmoth would be found on the island that would have a tongue exceeding 7 inches in length especially suited to eat this flower’s nectar. He noted in his diary "that such a moth exists in Madagascar may be safely predicted". 21 years later, just such a hawkmoth was indeed found, and named praedicta, or the one who can be predicted.

So what of the flickering insects outside my Lahore window? The long-tongued, sphinx like, predicted ones. Seen only around midnight and hovering on shimmering wings, they are sometimes confused with hummingbirds. How mysterious are these elusive sphinx likes being to the human eye.

In fact, hawkmoths are only one of four nectar feeders who have the ability to hover in the air. Such hovering, nectar-eating creatures are confined to families of the hawkmoths, hummingbirds (found only in the new world of the Americas), certain bats and hoverflies. The hawkmoth’s flying abilities have long been studied and one of their specialties is that they can side-slip while hovering around the flowers whose nectar they eat. They move from side to side like a skier aligning down a slope. This is thought to be a technique used to deal with ambush predators lying in wait within the flowers where they feed.

The punch line though is the Rangoon creeper itself that is the host for this tamasha. It offers irresistible, tubular and shining white flowers that are dazzling in the darkness of midnight for those creatures that will pollinate it when they come into contact with its flowers. Together with scent and sugary nectar, the hawkmoth must feel in perfect harmony with the flowers, its senses attuned to colour, smell, taste and shape. I cannot identify Lahore’s sub-species of hawkmoth, but I suspect it is a Macroglossum, or the long-tongued one.

And as if this wasn’t enough, researchers have discovered that the Rangoon creeper is a real charmer for many others in addition to the night flying hawkmoth.

This Asian tropical climbing plant using a fascinating method to diversify the way it attracts various visitors to its flowers is unusual in that its multi-shaded flowers are not just faded ones as are so many other flowers that alter their colour as they age. No the Rangoon creeper’s floral colour variation is quite deliberate. The white flowers, discovered to have the most nectar are special attractors for hawkmoths, the pinks, with less nectar, are for bees in the day’s sunshine as are the dark pinks for butterflies in the morning. A feast for so many, colour coded to perfection. They say it takes two to tango!

How hawkmoths and Rangoon creepers are eternally attracted to each other