“What is the loudest cicada” or “what is the loudest insect”, you might ask.
A recent BBC article says researcher John Petti as found the answer: Brevisana brevis, an African cicada, reaches 106.7 decibels — with the loudest North American cicada, Tibicen pronotalis walkeri at 105.9 decibels. Their sound was measured at a distance of 50cm (approximately 20 inches). Specifics about the equipment used and calibration of said equipment is not mentioned.
The article does introduce room for skepticism and debate, by noting that other species come very close (Diceroprocta apache), that the Tibicen pronotalis walkeri alarm call reaches 108.9 decibels, and a North American study that suggests decibels are correlated to body mass (and Brevisana brevis is not the most massive cicada).
According to the book Australian Cicadas by M.S. Moulds (New South Wales University Press, 1990) Cyclochila australasiae and Thopha saccata reach nearly 120db at close range. The “at close range” might be the key difference in measuring the sound, as Petti measured at a distance of 50cm.
I’ve measured Magicicada (the American periodical cicadas) calling around 110db at the “what if it sang next to my ear” distance, which of course, is not 50cm away. Magicicada chorus at around 80db:
Some people want to know how loud a cicada can get just because it is a cool fact to know, but others are concerned about noise-induced hearing loss (about which, I am not an expert). Both decibels and prolonged exposure seem to matter. According to the National Institute on Deafness and Other Communication Disorders page on Noise-Induced Hearing Loss, prolonged exposure to sounds over 85db can cause hearing loss (just above the chorus of a Magicicada). The WebMD harmful noise levels page has chainsaws and leaf blowers in the range of the loudest cicadas. Lessons learned: 1) Make sure you wear hearing protection if you plan on blowing leaves, or searching for the loudest cicada, and 2) Do not complain about the cicadas in your yard — complain about your neighbors and their leaf blowers.
There are over 3500 types of cicadas in the world, and for now Brevisana brevisis the king of the insect noisemakers.
More information on Petti’s study can be found here.