There is a large patch of wild gram plants right outside the classroom that I teach in. In between my classes I come outside, sit by it and watch all that goes on out there.
It was August. The first Gram Blue butterflies were fluttering onto the wild gram and laying their tiny flat eggs on the buds. Different butterflies seek out different plants for their caterpillars to eat. Some species may feed on a wide variety of plants while others, only on a specific few. The gram blue caterpillars would emerge in a couple of days.
Here, beneath the soil along the building, were the underground nests of black bull ants, the large fat black ants that we commonly find near our homes. If anybody trampled carelessly on the undergrowth here, the ants would send the intruder back running, tapping away the fierce insects off their feet.
In safe hands
The gram blue caterpillars look like little green slugs with black heads. The ants patrolling the ground below the gram plants sense the presence of these newborn larvae almost as soon as they hatch. The self-assigned, round-the-clock duty of the bull ants is to be the personal bodyguards of the larvae. Each larva may have two or sometimes three ants protecting it. They follow the larva whenever it crawls on the plant to feed in order to protect it. They survey the plant for predators. When the caterpillar nibbles into the wild gram pods to feed on the developing seeds, the bull ants stand guard at the entry hole. If you look closely at these creatures, you will see the ants tapping their antennae on the caterpillars. This is believed to be the language they use to communicate with each other. Studies have revealed that the caterpillar responds and communicates with its ant companions, through muscular contractions.
I saw a wasp once, perch on a wild gram with a caterpillar on it. As soon as the plant shook with the wasp’s arrival, the largest ant on duty charged at it with wide open mandibles and the predatory insect flew away fearing for its life. I decided to investigate the ants’ protective instincts a bit further. I took my finger close to the feeding larva, and after getting nailed a few times by the ants, I thought I would rather use a dry, frail twig. The ants would get furious each time the twig came anywhere close to it. They would either bite and snap it or grab it and toss it aside. Every now and then the gram blue caterpillar would secrete honey dew, a sugary bluish-green droplet, from a gland on its lower back and the bull ants would climb over and graciously gulp it down.
Such a symbiosis exists between the larvae of many butterflies and the ant species, where both organisms share a strong relationship till the larva becomes a pupa.
Life in nature isn’t always a struggle and competition for superiority, as is often portrayed. You find plenty of friendships too, across species, like the ant and the caterpillar. Have you heard about the bond between the honey guide and the badger? Here the bird leads the mammal to honey combs and the badger after collecting it, leaves some for the bird to eat. Or, about the hermit crab and the sea-anemone? Have you seen how cattle let the drongos and mynahs sit on their backs and pick off the ticks on their hide? Nature is also full of diverse and strange friendships and relationships, where organisms help and depend on each other to survive.
Conservation and Nature is a series brought to you by Kalpavriksh Environment Action Group (www.kalpavriksh.org)
