Music is heart and soul of everything in nature, from the wonderful calls of the beautiful avian and mammalian life to the rhythmic melody of the leaves swaying around in the breeze or the humming sound of wind, finding its way through the thick undergrowth, nature is filled with a lot of such amazing musical renditions.
A variety of these compositions have been used to depict a typical wilderness, especially, in a lot of movies, to give the viewer, a visual and an aural sense of the wild. But, nothing can be more closer or an apt depiction of any wilderness, than the resounding, resonating, constant buzzing and clicking sounds emanating from all around, echoing from the trees and shrubs………..with an eerie silence……… forming the interludes in the overall musical composition. The artists, that are responsible for these wonderful renditions, are the amazing little creatures called Cicadas.
Cicadas are insects that live in predominantly temperate to tropical climates, in a wide range of habitats. The ones that I have come across are the ones in the thick rainforests of Agumbe and in the more drier scrub and dry-deciduous forests outside of Bangalore. These insects are more commonly heard than seen.
Cicadas are insects in the order Hemiptera, suborder Auchenorrhyncha (which was formerly included in the now invalid suborder Homoptera). Cicadas are in the superfamily Cicadoidea. Their eyes are prominent, though not especially large, and set wide apart on the anterior lateral corners of the frons. The wings are well-developed, with conspicuous veins; in some species the wing membranes are wholly transparent, whereas in many others the proximal parts of the wings are clouded or opaque and some have no significantly clear areas on their wings at all. About 2,500 species of cicada have been described, and many remain to be described. Cicadas are often colloquially called locusts, although they are unrelated to true locusts, which are various species of swarming grasshopper. Cicadas are related to leafhoppers and spittlebugs.
As I mentioned before, Cicadas are more often heard than seen. The males of the species, to be more precise, are the ones that are capable of making these sounds. However, both the sexes have a membrane called the ‘tympana’, that aids in detecting sound, in effect hearing. The music of Cicadas have various connotations, from distress calls, to mating calls, to courtship calls in some species.
The calls of Cicadas are very loud and sometime very high-pitched too. Wikipedia says,
Some cicadas produce sounds up to 120 dB (SPL),among the loudest of all insect-produced sounds. This is especially notable as their song is technically loud enough to cause permanent hearing loss in humans, should the cicada sing just outside the listener’s ear. Conversely, some small species have songs so high in pitch that the noise is inaudible to humans.
Also, the calls are powerful enough to carry to distances and seem to echo from multiple directions. Cicadas are like the symphony artists of the forests, many of them, from many different trees, start calling in unison. This is just wonderful to experience. The symphony starts of with one call, the lead Cicada, and is immediately followed by many other Cicadas, just amplifying the whole thing. There is a lull, in between too, a complete silence, interlude of sorts, before it is picked up and the calling resumes in exactly the same manner. This whole musical performance, is not just one single, straight note, it is a multitude of notes with a lot of modulations in them as well. Also, have read that the species exhibit an elaborate pattern of time-sharing, probably to avoid interferences with the calls of other species, preventing acoustic interference. It all seems to so simple at first thought, but holds a great amount of detail when taken a deeper look. That is the reason, they are referred to as songs of Cicadas rather than just calls……
Cicadas possess an organ called the ‘tymbal’ in their abdomens, ( the orange rings in the image below, was pulling up and down while the Cicada was calling ) which is what they use to generate these sounds. The muscles around the tymbals are flexed, thus, pulling them in and out of shape, generating the clicking sound, when them gets amplified by their hollow abdomen.
Cicada ( from the scrub forests on the outskirts of Bangalore )
They feed on the sap of trees by inserting an extension called a proboscis, under their head into the stems of plants and trees. Another interesting thing that I came to know while reading up on them was that they spend a large part of their early life under the ground, feeding on the roots of trees and plants. They stay underground for different durations, depending on the species, like some may emerge out of the ground every year, or some might take as long as 2 to 17 years to emerge. I also noticed that they do have different coloration, depending upon the kind of habitats they are in. Like, this Cicada from the thick green rainforests of Agumbe and the next one from the relatively drier scrub forests on the outskirts of Bangalore. I guess, it’s all about helping them as a camouflage to disappear into the surroundings.
Cicada (from the rainforests of Agumbe )
Another Cicada ( from the dry scrub forests on the outskirts of Bangalore )
So, next time you are in a forest and hear the symphony of the clicking and buzzing sounds during the day or dusk, the artists would undoubtedly be the Cicadas. Night times are mostly the performances of Crickets, another bunch of artists of the insect world. Just, enjoy their performance……..
Here’s one such performance, ( src: Cicada Central )
PS: Next time, I should remember to record some audio and video as well…….
There are some wonderful resources on the web to know more about these wonderful insects. Didn’t know that Cicadas were quite a bit of a study subjects in many places, whole bunch of sites dedicated to them. Here are few of them…..