The long, buzzing, mechanical sound of a cicada is heard in Ontario towards the end of the summer, when it is most hot – those “Dog days of summer”. These are the Neotibicen (Tibicen) canicularis and are commonly known as dogday harvestfly or dog-day cicadas. Cicadas make the loudest sound of all insects. They sound like a power saw cutting wood and the sound often lasts for several seconds. It is the male cicada that makes the noise as they call to the females. The males have two elastic, circular membranes, called timbals and it is these special timbal organs that produce the sound. The rapid repetition of contraction and relaxation of the large timbal muscle makes the sound seem like a continuous sound. They can do this 120-480 times per second and the sound is increased by contractions of their abdominals, which expand air chambers in their mostly hollow abdomen.
I found a cicada exuvia, the abandoned exoskeleton, attached to our new shower, so I know there was action there quite recently, but whilst I heard it, I couldn’t see any adult cicadas around.
Cicadas have a really interesting life cycle. The female implants her eggs in a crevice she cuts into a twig. After 6 weeks the eggs hatch as nymphs. The nymphs drop to the ground and burrow underground, where they stay for three years, feeding on tree root juices. They are 8-feet down, so they have very strong front legs for digging. In the summer of their third year they crawl out of the ground and climb their host tree, parting with its exoskeleton along the way and emerge as adults. The adults are mostly black with green markings on its body and they have prominent eyes that are set wide apart. Once adults they do not eat and after they mate they fall from the trees and die. We see these cicadas every year, but some other species of cicadas are only seen every few years – some only every 13-17 years!