Forests provide a panoply of sounds — the chatter of monkeys, the sweet notes of the Malabar whistling thrush, the gossip-laden conversations of the babblers, the phenomenal orchestra provided by the frogs after a good rain shower.
Every self-respecting forest, however, will eventually lay claim to this one creature — an insect with the skills and stamina to match any opera singer. Welcome to a cacophonous world — the world of the insect — the cicada.
There may be many of us who not have seen a cicada, but we must surely have heard it at some time or the other.
That incessant sound, which goes "zee-e-e zee-ee zee-e-e", which while annoying to a layperson must be music to a nature lover’s ears!
About 2,500 species of cicada exist in the world. The insect belongs to the family Cicadidae and order Hemiptera (true bugs).
With a body length of 2 to 5 cm, they appear to be a larger version of the house fly. They have two large eyes which are set wide apart. In some species the wing membranes are transparent.
They have short antennae too. In semi-deciduous habitats, cicadas are grey and brown and in the forests, there are the red and green variants.
The orange-red cicada is one of the beautiful cicadas that are found in the forests. It has a red body, red eyes and black wings with yellow patches.
During one of our trips to the evergreen forests in the Uttara Kannada district (Karnataka), we spotted two of them on the bark of a tree, actively walking up and down and then appearing a colourful red when in flight from the bark of one tree to another.
Their singing, however, seemed not in sync with each another. On our approach they would try to hide behind the bark or fly away to a distant tree.
This one experience, however, at the Biligiri Rangana Hills (again, in Karnataka) during the month of May remains unforgettable.
Come summer, cicadas become very active and we were treated to a noisy musical performance, a la heavy metal here in the hills. While we were walking along the forest path, thousands of these insects started singing synchronously, making us feel they were present in each and every tree.
Having detected our presence, they reduced their pitch only to come to a complete stop and alert the neighbouring cicadas after which something amazing happened.
The sounds seemed to adhere to a pattern — getting fainter and fainter for over half a mile as we crossed the streams, climbed the hills — only to amplify later and reach us from another direction.
Apparently, all these sounds were only from the males to attract mates! Females cannot make sounds, although they can hear.
Sounds are produced by a mechanism using drum-like tymbal organs in the abdomen above their hind legs. Cicada calls can be heard a mile away — a series of powerful clicks, monotonous and reverberating across the forests.
The life cycle of a cicada is one of the most interesting ones in the natural world.
They live as nymphs in the underground for many years and as adults for only a few weeks.
Nymphs do not have wings but the adult cicada develops wings much larger than its body.
They emerge from underground tunnels depending on the soil temperature, warming up for a couple of days for their body and wings to become hard and living only for a few weeks. They fly tree to tree and after feeding, start calling out loudly to attract females.
The female cicada slits tree branches using an organ known as an ovipositor and lays hundreds of eggs in it.
The young ones hatch and they drop down the branches and burrow deep in the soil.
A species of American cicada well known as Magicicada (North Carolina Brood 2 cicada) lives very long in the underground for up to 13-17 years, feeding on the saps of the roots of trees.
When the soil temperature becomes favourable in spring, millions of nymphs in their final stages emerge from the underground tunnels on every single acre of land.
The most recent invasion was between late May and end of June 2013. This is one of the greatest outbreaks in the insect world and one that attracts many predators — ants, praying mantis, birds, rodents, wasps, turtle and even fish.
