Unweaving the Secret Life  of Oecophylla - the Weaver Ant

You can't miss weaver ants. Conspicuous as they may be in their red-brown splendour (and of course, their infamous bite), they live in a world unimaginably different from ours. Called Oecophylla smaragdina  in the language of science, their binomial name roughly translates to "one who dwells in leaves" (oeco + phylla), and "emerald", as in some places, these ants have green gasters₁.

Say hi!

Note that they dwell in leaves, and not on them. Weaver ants are adept in making leafy nests, hence the name. Found commonly on fruit-trees, groups of ants hold leaves that are still on branches in place, while others fetch larvae(baby ants!) which secrete a gauze-like material which is in turn used in gluing the leaves to one-another to build a nest.

A closeup of a nest; leaves are 'glued' to one-another

A weaver ant nest in its full glory!

An abandoned nest built on an Australian Wattle tree. Nests can differ in size, ranging from fist-sized to human-child sized.

 A finished nest is a spectacle indeed; it is a patchwork-quilt of sorts. A gentle tap, and swarms of major workers₂ emerge, some drawing themselves up to their fullest height and flicking their gasters threateningly in a synchronized rhythm, others alerting nestmates of potential danger. (Workers are of two kinds; the relatively large 'major' workers who emerge when attacked, and the small 'minor' workers which mostly stay inside, but will emerge occasionally).

You don't want to get bitten by one of these; they refuse to get their jaws off your skin ( if I were a weaver ant and you came nosing into my nest's affairs, I wouldn't either!), and have to be pulled out by the gaster. Plus, you get the added benefit of being sprayed with formic acid!

A horde of major workers guarding the entrance

Carrying home the remains of Men lost on the frontline (Women, in this case)

Weaver ants are fiercely territorial. Intruders, both ant and non-ant, will be spread-eagled and ripped apart into manageable pieces if they are small enough. Colonies typically span a few nests on the same tree, or sometimes a few trees. The Queen Ant₃ is quite large, green in colour, and has a larger body in proportion to the head when compared to the workers. She is queenly indeed! When weaver ants are on a mission but their path is not contiguous enough, they construct, in a most remarkable manner ,live bridges constituted of ant bodies, legs locked in a chain across the chasm to be crossed.

Weaver ants are much feared, by humans and by others. This reputation that Natural Selection has bestowed on weaver ants, is, unsurprisingly, exploited by wily impostors. A jumping spider, Myrmarachne plataleoides, has evolved to look exactly like a worker ant. The spider is almost indistinguishable from the worker. To look more ant-like, the spider even waves its first pair of legs in the air, which resembles the way a weaver ant's antennae move. The female is a perfect mimic, but the male is given away by his large pedipalps_4.    

A wild-goose chase, and the con-woman was trapped! (Myrmarachne - female).

Notice the very weaver-esque eye-spots; those aren't eyes at all!

<sub>Tense yet composed, united yet independent, appalling yet fascinating, the weaver ant is an intriguing creature to both the layman and the scientist. It is yet another surprise that lays hidden in the verdure of dense cryptic canopies.

Footnotes:

1. The posterior-most portion of an ant; the portion behind their characteristic lean 'waists'

2. In some ants, there are many kinds of workers which can be classed as major/median/minor workers and so on, depending on their size and their role in the colony

3. The Queen is the only ant in the colony capable of laying eggs. Workers are females, but do not lay.</sub>

4. Pedipalps are appendages on a spider's face which serve like arms.

All photos were taken in the Indian Institute of Science campus with a phone's camera.

Photo Courtesy: Pranav Minasandra and Pooja Nathan

Measuring beauty in millimetres

“It has long been an axiom of mine that the little things are infinitely the most important.” ~ Arthur Conan Doyle.

We miss the little things. Wolves are much more prominent than wasps. This is the way our minds have evolved. Four billion years of evolution has led us to this: we are programmed to pay attention to things we consider big: Elephants and lions, wolves and hyenas, coconut palms and eagles. It is rare to run into people who actually like to look at ants with smiles on their faces. But once you are one of them, there is no going back. Beauty is in the little things.

A moss seems to be a carpet on wet floors. Why, it even feels like one! Surprising, isn't it, that when we look closer, the moss takes up a form and dimension you never thought possible? 

A moss' sporophytic parts standing out

Mosses are quite fascinating. They belong to the division of plants called the bryophytes. Amphibians of the plant kingdom. 

If you took any of the cells of your body, and kept it under a microscope powerful enough,after staining it with an appropriate stain, such as acetocarmine, you would see forty-six discrete packets of DNA, which scientists refer to as chromosomes. The interesting thing is that these are actually twenty-three pairs: each pair has two chromosomes: one from your mother, another from your father. This is the case in most animals, and so many plants. However, if you took an egg-cell, or a sperm-cell, they would have only twenty-three. Twenty-three is said to be the ploidy of human beings. If a cell has twenty-three chromosomes, it is haploid. If it has forty-six, it is said to be diploid. 

Different organisms have different ploidies. The ploidy of a dog is thirty-nine, so a dog's cells will have seventy-eight chromosomes. Cats have thirty eight. Butterflies have three-hundred and eighty. A fern called Ophioglossum has a staggering thousand two-hundred and sixty chromosomes.

Not all organisms have cells which are diploid. The wheat you eat, for instance, is hexaploid. It has a number of chromosomes six times its ploidy. Male honeybees, called drones, are haploid in all their cells. They have only one set of chromosomes, from their mother, the Queen. Here is where the moss becomes interesting.

In that picture up there, the green, leafy part is haploid. For a large part of the moss' life, it forms its entire body. It has organs for sexual reproduction: The male part is called the antheridium, and the female part is called the archegonium. But, once the sperm of the moss fertilises the egg, something magical happens. A diploid sporophyte pushes its way through the haploid gametophyte. A sporophyte has two parts: a long thread-like seta, and crowning it, a capsule, containing many more haploid spores, which will all give birth to plenty of new mosses. And so the moss perennates. 

A bounty of information lies hidden in that little carpet of green spread out on a bare patch of wet rock, or a moist stretch of brick wall. Every little thing has its own secrets, hidden from our sight. It is up to us, to discover them.