What makes that buzzing sound at night?

Almost everyone notices the buzzing sound as the sun goes down in the summer. Cicadias' songs trigger memories of long, hot nights and family camping trips. But I didn't know there was so much I didn't know about the bugs.

According to Wikipedia there are 2,500 species of cicada around the world, and each species sings a different song. Michigan has 10 species of cicadias identified.

They stay high up in the trees and are seen rarely. The males produce sound by vibrating abdominal drums called timbals. The noise is among nature's loudest sounds at 100 decibels or more at a distance of one inch.

After mating, females lay eggs in the bark of a tree. The eggs hatch after six to seven weeks and the cicada juveniles or nymphs burrow underground and begin feeding on roots. Their life cycles are long. Depending on the species of cicadia, they can spend 2 to 17 years underground as juveniles and then about 2 to 6 weeks as adults singing and mating.

When the 1-1.5 inch nymphs emerge from the ground, they climb a tree, puff up their exoskeletons until it splits lengthwise down the back and the adult cicadas slowly emerge. You can often find these ghostly shed skins still intact at eye level on tree trunks.

Cicadas do not sting, bite or carry diseases and they don't hurt the trees. In fact the presence of cicadas is usually a sign of a robust forest. To look at the species found in Michigan and listen to their different songs click HERE to go to The University Of Michigan-Museum of Zoology-Insect Division-Cicadas of Michigan website.