Annual Cicadas: The Musicians of Summer

Fast Facts about the annual cicada

  • While they appear every year, their life cycle does take longer than one year to complete. Most spend 2-5 years underground as nymphs before emerging as adults
  • Annual cicadas are usually a mix of black, gold, and green and can be up to 2 inches long
  • They go by many names with some folks calling them locusts and others using terms like dog-day cicada, swamp cicada, or even harvest flies

Cicadas are really fascinating representatives of the true bug group (Order Hemiptera) and are most famous for their noise-making abilities. There are over 1,300 species of cicada across the world and they all look fairly similar with wide set eyes on their head, a body that tapers toward the posterior end, and four membranous wings. Here in the US we have lots of different cicadas but two are the best known; the periodical cicada that emerges every 13 or 17 years and the annual cicada.

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Annual cicada adult (Photo by Ivy Orellana; UNL Entomology)

Annual cicada life cycle

Cicada females lay their eggs in a slit they cut into tree branches. Their ovipositor is long and sword-like to help create this tiny wooden nursery. Eggs hatch inside of the branch and the nymph will fall down to the ground and burrow below ground to feed in the tree’s root zone. As a true bug, or Hemipteran, cicadas have piercing-sucking mouthparts that help them to siphon juices from the tree. These juices are quite nutrient poor so it takes cicadas a while to grow. Imagine if you drank and ate nothing but Sprite, you wouldn’t grow too fast either! After 2-5 years below ground that are ready to emerge from the soil, climb up a tree or other tall vertical object and go through a final molt into adulthood. Adults usually live for 1-2 months to mate and create another generation of cicadas.

Noise-making

One of the reasons people know about cicadas is that they are capable of producing loud noises. These are mating calls made by the male in order to attract and secure a mate. If you would like to hear some of these “songs” you can visit this website: http://www.cicadamania.com/audio/

Other noise-making insects, like grasshoppers and crickets, use stridulation to create noise. This is where insects rub their leg along their abdomen or flick their wings to create a chirp. Cicadas create noise using an abdominal muscle called a tymbal to create a clicking noise. This noise then reverberates through their largely hollow abdomen until it creates that song we all know so well.

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Internal anatomy of a male cicada. Diagram courtesy of: http://www.robinsonlibrary.com/science/zoology/insects/hemiptera/cicadas.htm

Control

Typically control of cicadas is completely unnecessary. They can cause small amounts of damage with their egg laying but the nymphal feeding underground is not enough to damage trees. Small, young trees that people are worried about, can be covered with a cheesecloth cover.

More on Cicada ID: http://www.cicadamania.com/cicadas/category/types/tibicen/

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