Monday, June 8, 2015

Teenage Bugs are Having Sex in your Trees

If you live in Nebraska or a nearby state, millions of insects will be emerging this May and June, maybe even in your backyard! They are called periodical cicadas and they’re one of nature’s most interesting insects. As nymphs they live in the soil for 17 years feeding on sap from the roots of trees. This makes them the longest living insect in North America. After that 17 year period is up, they emerge from the soil, molt into their final adult form, and take to the trees above them to mate. They emerge in what we call “broods” and and we live in Brood 4's territory. 

Periodical cicada completing its molt into an adult,  photo by Bob Rabaglia.

In order to find one another and mate, cicadas will sing songs. The male produces the loudest portion of the the tune by flexing his tymbals. Tymbals are small membranes between the thorax and abdomen that can be vibrated by a powerful muscle behind them. This flexing produces clicks which are amplified by the cicada's hollow abdomen. The males often gather into groups and create a chorus which can make quite a racket, reaching decibel levels comparable to a jet airplane engine. The females are not silent in this song and create clicking sounds using their wings. This completes the duet and signals acceptance of a mating partner.

Male cicada and his tymbal

ID facts
  •  All periodical cicadas are black, with red eyes, and orange trim on their wings.

  • There are 3 species of periodical cicada and to tell them apart you need to look at their belly. Magicicada cassini will have an all-black abdomen, M. septendecim will have big thick orange stripes, while M. septendecula will have thin orange stripes.
  • You can use their mating calls to ID them as well. Head to to learn more about cicada calls. You can help researchers who want to know more about periodical cicadas by filling out the citizen science forms also found at

Control help

Periodical cicadas are not normally pests but occasionally harm fruit trees or newly transplanted trees with their egg laying activity. The female has a sword-like ovipositior that she uses to slice small slits into young tree branches and then to insert her eggs. This can result in weakened branches that snap and create a characteristic "flagging" damage (see image below). Older, more established trees can handle this, but young ones may be stressed by this flagging damage. If you are worried about one of your trees, your best course of action will be to take some fine, mesh netting and wrap it around the trees branches to keep the females from landing on them. 

Top photo: Cicada flagging damage on young tree (Photo by Dan Potter)
Bottom photo: Using netting to protect tree from cicada egg laying 

This is a unique natural phenomenon to be a part of so check your trees or head out to a local state park to meet some of these amazing insects!