Environment

Besides their ear-splitting screech from the bush – how much do you know about cicadas?

Frieda Paton

I was showing a visitor from Holland to his room when he stopped suddenly, looked up towards the trees with a shocked expression, and asked, “What’s that?”

It took me a few seconds to realise that he was referring to the ear-splitting shrill screech of a cicada. At this time of the year, this sound is so common to us that we hardly even notice it!

The noise, I explained, was just from an insect, a bug called a cicada – then realised that I had no further information to give. I was quite ashamed, considering that I’ve lived with the summer song of the cicada for over six decades. Thank you Google – next time I can provide a lot of interesting detail.

First of all, unlike the case with most insects, the cicada’s song doesn’t come from clicking their wings or rubbing their legs together. Only the male cicada makes this sound and it’s his call to attract a mate. He produces his song with drum-like organs in his abdomen called tymbals. The tymbals are made up of a series of membranes which are pulled in and out by small muscles so rapidly that it becomes one continuous sound, while his hollow-body serves as a soundbox.

The shrill call of the cicada can reach up to 108 decibels or more – a level which can produce a noise-induced hearing loss in humans after extended exposure. No wonder that, while sending out his mating call, the male cicada can disable his tympana – the structure which cicadas use to detect sound.

Cicadas may be mistaken for a moth or cricket but they belong to the Hemiptera, or true bug, family – at least that part I got right inadvertently. They are quite large insects, with most species varying between 2cm to 5cm in length. They also vary in colour. Some are quite colourful while others are plain brown, which serves as camouflage in the trees where they live. There are over 3000 species across the world and around 150 different species have been identified in South Africa.

Cicada larvae are low in fat and high in protein, making for a healthy snack. Mostly for animals, but you might want to add them to your next stir-fry dish – like many other people around the world.

Caption: Palypleura Haglundi (orange wing cidada)

Image attribution: Bernard DUPONT from FRANCE, CC BY-SA 2.0 via Wikimedia Commons

 

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