Campus notes on Natural History – The Wild Banana

A few years ago on a field trip to Singheshwar some teachers had brought back saplings of wild banana (Musa acuminata or Musa salaccensis) and had planted two of the three saplings on the side of the road leading from Jr. Auditorium to the Dining Hall (DH). The saplings survived but would not do much apart from leaving out a few leaf shafts in monsoon and drying up to inconspicuous stumps in the dry season.

This monsoon, one plant surprised many of us by growing plenty of leaf shafts and also a flower bud. The flowering started soon after and following are some observations on the pollination ecology of the plant.

The flower in bloom
The flower in bloom

I have been looking up on the jelly like secretion of the wild banana flower that has been blooming opposite the Senior Audi. The secretion was strange because I had never seen any flower do this with the only exception being the ferns that secrete a watery sweet fluid to attract ants that in turn keep the herbivores at bay.

I found that the jelly like secretion is a nectar concentrate of about 15-20 % sucrose (anyone who tastes it can verify this) and is primarily an adaptation based on its pollinator choice. Turns out that the wild banana prefers vertebrates (bats and birds) to invertebrates (insects) to help with pollination in it’s natural habitat (jungles of South East Asia). This behavior is termed as “Pollinator Syndrome” and “Zoophily” is the term given to vertebrate driven pollination.

The jelly secretion
Close-up of the flower: the jelly like secretion

I was not a little disappointed when I checked one morning, after assembly, to find that ants were on the nectar because one of the reasons to make the nectar viscous and sticky is to discourage insects. On closer examination I realised that only the last set of inflorescence (group flowering) was ant infested as the jelly had begun to dehydrate and ferment (tastes a little like Neera as Amresh put it). The fresh inflorescence and jelly secretion (happens overnight) was untouched by the ants! Nature had contrived to give evidence to confirm the need for the jelly, with a control right beside it and I almost dismissed it!

Bananas do not need pollination to develop fruits. In the absence of other plants nearby it seems they can self-pollinate and give seedless fruits (Parthenocarpy). This process is known as parthenogenesis. All we need to do is hope the fruits develop fully and then cut one open and see if the seeds have developed.

A few days ago I saw a hornet wasp on the banana plant at around 9:00 AM. I wonder if this contradicts the zoophily theory of pollination syndrome.

The jelly can keep out only the insects!
The jelly can keep out only the insects!

– Arun Kumar

References:

https://en.wikipedia.org/wiki/Zoophily

www.jstor.org/stable/2388300

 

Colours of Sahyadri

Nature was, for the longest period of time, something I had read about or oohed and aahed over when I went on picnics and vacations. The words to describe the sights would come easily to anyone who has read any travel article—the cerulean blue of the sky, the fluffy clouds that look like cotton candy, dewdrops shining like diamonds on blades of grass, a lake shimmering like a sheet of glass, the brilliant disc of the full moon, the ink-blue night sky dotted with crystals, the stormy grey of a rain-cloud filled sky—I could go on and on…

Little did I imagine that I would one day be living in the midst of all those words I had read! I had first visited Sahyadri towards the end of March. The hillsides were dappled with shades of brown. Green was visible in patches on tree tops and the lake was far, far away looking as though someone had accidentally set a large sheet of glass with jagged edges in the valley.

I came back towards the end of May and the colours had not changed much—the bright blue sky overhead, the Impressionist orange-red glow of the sunsets, the varying shades of grey-blue on the lake’s surface, mirroring the porcelain white clouds.

... the Astachal sky
… the Astachal sky

The monsoon blew into Sahyadri and how the landscape changed! A riot of colours unfurled itself. The greens came first, from the palest yellow-green of baby leaves to the deep, dark rich green of the older ones who had seen a few summers. The blue of the sky changed to iron grey, molten grey and silver grey depending on the whims of the rain gods. The white clouds turned grey and then black with the effort of holding in all the raindrops. Then came the flowers in the deepest of butter yellows to the fieriest of reds, oranges, an artist’s palette of blues and violets, and the babiest of baby pinks, milky whites, and waxy creams. The jagged edges of the glass lake seemed to smoothen themselves out and reflect the spectacle of the grey and black skies.

Bheema at the outset of the Monsoon
Bheema at the outset of the Monsoon

I have been here for four months now and each day has brought fresh enchantment as I watch the myriad shades of sunshine through the leaves, butterflies clad in the colours of the skies, the leaves and the flowers, and make fresh discoveries, such as the pale-green Moon Moth, the fierce-looking Owl Moth, the humongous Atlas Moth.

I now look forward to the next term and seeing the greens fade into yellows and the yellows into browns, the skies regaining their porcelain shimmer, the clouds their candy fluff, and the sunsets their vibrant oranges.

– Seema Srinivas