Last winter’s eve, late one night, a dainty Cicada invited itself into my dining room and having done so, proceeded to perch atop my glass topped dining table.
Ever the one to seize an opportunity, I carefully slid a sheet of paper underneath it, and proceeded to take a few pictures. Seemingly unperturbed, the Cicada continued to pose and thus encouraged by it’s exhibitionist streak, I snagged the following photographs using a Canon EOS 5D Mark III with Canon EF 100mm f/2.8L Macro IS USM lens and illuminated by a Canon MT-24EX macro twin light flash.
The cicada’s claim to fame is its raucous, incessant singing, which is in fact, a mating call, belted out by males for the express purpose attracting a mate, with each species having a distinctive call, thus allowing several species to co-exist.
The sound producing apparatus of a Cicada is surprisingly complex; Scientists still do not fully comprehend it. The sound producing organs, a pair of ribbed membranes called tymbals, are located at the base of the abdomen. A Cicada sings by contracting it’s internal muscles, causing them to buckle inward and produce a distinct sound. The muscles, when relaxed, pop right back to their original position.
The calls of some large species of Cicada range well in excess of 120 decibels at close range, approaching the pain threshold of human hearing. Other smaller species sing at such high frequency rates so as to remain imperceptible to human ears and yet cause animals with a keen sense of hearing, such as dogs, to howl in pain.
Cicadas usually sing during the hottest period of the day. In addition to attracting a mate, the call also serves to repel avian predators, playing havoc with their hearing, disrupting communication and generally making group foraging a difficult proposition. Male cicadas of the same brood also tend to synchronize their calls, thereby maximizing the total volume of sound produced and benefiting the entire brood.
But even cicadas need to protect themselves from the din they produce. Both male and female cicadas possess a pair of large, mirror-like membranes called tympana, which function as ears. The tympana are connected to an auditory organ by a short tendon, which retracts upon singing, creasing the tympana and preventing it from being damaged.
Although Cicadas are often mistaken for locusts, they’re more closely allied to plant & leaf hoppers, which they’re classified together with, in the insect order Hemiptera. Entomologists have identified more than a thousand species of cicadas, the world over, with many more still awaiting discovery.
The average wingspan of a cicada varies between 2.5 to 15 cm., depending on the species. Like most insects, they possess two pairs of wings, which are folded along the sides of their body, when not in use.
Large compound eyes situated on either side of their head affords them a wide peripheral vision, while three simple eyes (also known as ocelli) situated on the top of head allow them to keep a watch out for aerial predators. Behind the ocelli are located a pair of small, bristle like antennae, which serve as sensory organs.
A cicada’s mouth parts are enclosed in a long, thin, beak-like sheath, called the labium, which contains four needle-like stylets used for feeding, which are retracted and tucked away between the legs during times of disuse. Cicadas feed on plant sap, utilizing their mouth parts much the same way humans use drinking straws.
Mating occurs when a female cicada finally succumbs to the romantic ballad of an eager suitor, following which, eggs are deposited inside plant stems with the help of an ovipositor, a specialized egg laying organ located at the extremity of the female abdomen.
The eggs eventually hatch into small, wingless nymphs which on falling to the ground, burrow and feed on root sap, even as they continue to grow in size, molting at regular intervals.
On nearing adulthood, the nymphs proceed to dig their way to the surface with the help of specially modified forelegs, which function as tiny shovels. Surfacing well after dusk, during late spring or early summer, they seek high ground, where they undergo ecdysis one last time before emerging as fully formed, winged adults.
Adult Cicadas live for a few short weeks, disappearing just as mysteriously as they appeared, often falling prey to birds and other predators in large numbers. Below ground, nymphs are eagerly sought out and devoured by predacious beetle larvae.
Thus, in conclusion, Cicadas are largely overlooked and criminally understudied, which neither bite nor sting and while large numbers of them may slow down tree growth, owing to their sap sucking tendencies, they cause no permanent damage and are largely harmless.
The worst they are capable of, is annoying people with their fever pitch singing.
But then again, everyone’s a critic! 😉
Thanks to Javed Ahmed for helping me to write this blog.